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2019

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Steib S, Klamroth S, Gassner H, Pasluosta C, Eskofier B, Winkler J, Klucken J, Pfeifer K
Exploring gait adaptations to perturbed and conventional treadmill training in Parkinson's disease: Time-course, sustainability, and transfer.
2019 Hum Movement Sci, Band: 64, Seiten: 123 - 132
KurzfassungBackground Gait impairment is a major motor symptom in Parkinson’s disease (PD), and treadmill training is an effective non-pharmacological treatment option. Research question In this study, the time course, sustainability and transferability of gait adaptations to treadmill training with and without additional postural perturbations were investigated. Methods 38 PD patients (Hoehn & Yahr 1–3.5) were randomly allocated to eight weeks of treadmill training, performed twice-weekly for 40 min either with (perturbation treadmill training [PTT], n = 18) or without (conventional treadmill training [CTT], n = 20) additional perturbations to the treadmill surface. Spatiotemporal gait parameters were assessed during treadmill walking on a weekly basis (T0–T8), and after three months follow-up (T9). Additional overground gait analyses were performed at T0 and T8 to investigate transfer effects. Results Treadmill gait variability reduced linearly over the course of 8 weeks in both groups (p < .001; Cohen’s d (range): −0.53 to −0.84). Only the PTT group significantly improved in other gait parameters (stride length/time, stance-/swing time), with stride time showing a significant between-group interaction effect (Cohen’s d = 0.33; p = .05). Additional between-group interactions indicated more sustained improvements in stance (Cohen’s d = 0.85; p = .02) and swing time variability in the PTT group (Cohen’s d = 0.82; p = .03) at T9. Overground gait improvements at T8 existed only in stance (d = -0.73; p = .04) and swing time (d = 0.73; p = .04). Discussion Treadmill stride-to-stride variability reduced substantially and linearly, but transfer to overground walking was limited. Adding postural perturbations tended to increase efficacy and sustainability of several gait parameters. However, since between-group effects were small, more work is necessary to support these findings.

2018

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Lachner-Piza D, Epitashvili N, Schulze-Bonhage A, Stieglitz T, Jacobs J, Dumpelmann M
A single channel sleep-spindle detector based on multivariate classification of EEG epochs: MUSSDET.
2018 J Neurosci Meth, Band: 297, Seiten: 31 - 43
KurzfassungStudies on sleep-spindles are typically based on visual-marks performed by experts, however this process is time consuming and presents a low inter-expert agreement, causing the data to be limited in quantity and prone to bias. An automatic detector would tackle these issues by generating large amounts of objectively marked data. NEW METHOD: Our goal was to develop a sensitive, precise and robust sleep-spindle detection method. Emphasis has been placed on achieving a consistent performance across heterogeneous recordings and without the need for further parameter fine tuning. The developed detector runs on a single channel and is based on multivariate classification using a support vector machine. Scalp-electroencephalogram recordings were segmented into epochs which were then characterized by a selection of relevant and non-redundant features. The training and validation data came from the Medical Center-University of Freiburg, the test data consisted of 27 records coming from 2 public databases. RESULTS: Using a sample based assessment, 53% sensitivity, 37% precision and 96% specificity was achieved on the DREAMS database. On the MASS database, 77% sensitivity, 46% precision and 96% specificity was achieved. The developed detector performed favorably when compared to previous detectors. The classification of normalized EEG epochs in a multidimensional space, as well as the use of a validation set, allowed to objectively define a single detection threshold for all databases and participants. CONCLUSIONS: The use of the developed tool will allow increasing the data-size and statistical significance of research studies on the role of sleep-spindles.
Asplund M, Welle CG
Advancing Science: How Bias Holds Us Back.
2018 Neuron, Band: 99, Nummer: 4, Seiten: 635 - 639
Valle G, Petrini FM, Strauss I, Iberite F, D'Anna E, Granata G, Controzzi M, Cipriani C, Stieglitz T, Rossini PM, Mazzoni A, Raspopovic S, Micera S
Comparison of linear frequency and amplitude modulation for intraneural sensory feedback in bidirectional hand prostheses.
2018 Sci Rep-uk, Band: 8, Nummer: 1, Seite: 16666
KurzfassungRecent studies have shown that direct nerve stimulation can be used to provide sensory feedback to hand amputees. The intensity of the elicited sensations can be modulated using the amplitude or frequency of the injected stimuli. However, a comprehensive comparison of the effects of these two encoding strategies on the amputees’ ability to control a prosthesis has not been performed. In this paper, we assessed the performance of two trans-radial amputees controlling a myoelectric hand prosthesis while receiving grip force sensory feedback encoded using either linear modulation of amplitude (LAM) or linear modulation of frequency (LFM) of direct nerve stimulation (namely, bidirectional prostheses). Both subjects achieved similar and significantly above-chance performance when they were asked to exploit LAM or LFM in different tasks. The feedbacks allowed them to discriminate, during manipulation through the robotic hand, objects of different compliances and shapes or different placements on the prosthesis. Similar high performances were obtained when they were asked to apply different levels of force in a random order on a dynamometer using LAM or LFM. In contrast, only the LAM strategy allowed the subjects to continuously modulate the grip pressure on the dynamometer. Furthermore, when long-lasting trains of stimulation were delivered, LFM strategy generated a very fast adaptation phenomenon in the subjects, which caused them to stop perceiving the restored sensations. Both encoding approaches were perceived as very different from the touch feelings of the healthy limb (natural). These results suggest that the choice of specific sensory feedback encodings can have an effect on user performance while grasping. In addition, our results invite the development of new approaches to provide more natural sensory feelings to the users, which could be addressed by a more biomimetic strategy in the future.
Timotius IK, Canneva F, Minakaki G, Pasluosta C, Moceri S, Casadei N, Riess O, Winkler J, Klucken J, von Horsten S, Eskofier B
Dynamic footprints of alpha-synucleinopathic mice recorded by CatWalk gait analysis.
2018 Data in Brief, Band: 17, Seiten: 189 - 193
KurzfassungCharacterizing gait is important in the study of movement disorders, also in clinical mouse models. Gait data are therefore necessary for the development of gait analysis methods and the study of diseases. This article presents gait data of two α-synucleinopathic transgenic mouse models and their non-transgenic littermate, backcrossed into the C57BL/6N genetic background. The animal gait was recorded using CatWalk system, which provides the information for each run about the paw positions, paw print sizes, and paw intensities as a function of time or video frame. A total of 90 run data files are provided in this article.
Vomero M, Castagnola E, Ordonez JS, Carli S, Zucchini E, Maggiolini E, Gueli C, Goshi N, Ciarpella F, Cea C, Fadiga L, Ricci D, Kassegne S, Stieglitz T
Electrocorticography Arrays: Incorporation of Silicon Carbide and Diamond-Like Carbon as Adhesion Promoters Improves In Vitro and In Vivo Stability of Thin-Film Glassy Carbon Electrocorticography Arrays
2018 Advanced Biosystems, Band: 2, Nummer: 1
KurzfassungThin-film neural devices are an appealing alternative to traditional implants, although their chronic stability remains matter of investigation. In this study, a chronically stable class of thin-film devices for electrocorticography is manufactured incorporating silicon carbide and diamond-like carbon as adhesion promoters between glassy carbon (GC) electrodes and polyimide and between GC and platinum traces. The devices are aged in three solutions—phosphate-buffered saline (PBS), 30 × 10−3 and 150 × 10−3m H2O2/PBS—and stressed using cyclic voltammetry (2500 cycles) and 20 million biphasic pulses. Electrochemical impedance spectroscopy (EIS) and image analysis are performed to detect eventual changes of the electrodes morphology. Results demonstrate that the devices are able to undergo chemically induced oxidative stress and electrical stimulation without failing but actually improving their electrical performance until a steady state is reached. Additionally, cell viability tests are carried out to verify the noncytotoxicity of the materials, before chronically implanting them into rat models. The behavior of the GC electrodes in vivo is monitored through EIS and sensorimotor evoked potential recordings which confirm that, with GC being activated, impedance lowers and quality of recorded signal improves. Histological analysis of the brain tissue is performed and shows no sign of severe immune reaction to the implant.

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Vomero M, Zucchini E, Delfino E, Gueli C, Mondragon NC, Carli S, Fadiga L, Stieglitz T
Glassy Carbon Electrocorticography Electrodes on Ultra-Thin and Finger-Like Polyimide Substrate: Performance Evaluation Based on Different Electrode Diameters.
2018 Materials, Band: 11, Nummer: 12, Seite: 2486
KurzfassungGlassy carbon (GC) has high potential to serve as a biomaterial in neural applications because it is biocompatible, electrochemically inert and can be incorporated in polyimide-based implantable devices. Miniaturization and applicability of GC is, however, thought to be partially limited by its electrical conductivity. For this study, ultra-conformable polyimide-based electrocorticography (ECoG) devices with different-diameter GC electrodes were fabricated and tested in vitro and in rat models. For achieving conformability to the rat brain, polyimide was patterned in a finger-like shape and its thickness was set to 8 µm. To investigate different electrode sizes, each ECoG device was assigned electrodes with diameters of 50, 100, 200 and 300 µm. They were electrochemically characterized and subjected to 10 million biphasic pulses—for achieving a steady-state—and to X-ray photoelectron spectroscopy, for examining their elemental composition. The electrodes were then implanted epidurally to evaluate the ability of each diameter to detect neural activity. Results show that their performance at low frequencies (up to 300 Hz) depends on the distance from the signal source rather than on the electrode diameter, while at high frequencies (above 200 Hz) small electrodes have higher background noises than large ones, unless they are coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS).
Vomero M, Ashouri D, Oliveira A, Eickenscheidt M, Stieglitz T
Graphitic Carbon Electrodes on Flexible Substrate for Neural Applications Entirely Fabricated Using Infrared Nanosecond Laser Technology.
2018 Sci Rep-uk, Band: 8, Nummer: 1, Seite: 14749
KurzfassungNeural interfaces for neuroscientific research are nowadays mainly manufactured using standard microsystems engineering technologies which are incompatible with the integration of carbon as electrode material. In this work, we investigate a new method to fabricate graphitic carbon electrode arrays on flexible substrates. The devices were manufactured using infrared nanosecond laser technology for both patterning all components and carbonizing the electrode sites. Two laser pulse repetition frequencies were used for carbonization with the aim of finding the optimum. Prototypes of the devices were evaluated in vitro in 30 mM hydrogen peroxide to mimic the post-surgery oxidative environment. The electrodes were subjected to 10 million biphasic pulses (39.5 μC/cm2) to measure their stability under electrical stress. Their biosensing capabilities were evaluated in different concentrations of dopamine in phosphate buffered saline solution. Raman spectroscopy and x-ray photoelectron spectroscopy analysis show that the atomic percentage of graphitic carbon in the manufactured electrodes reaches the remarkable value of 75%. Results prove that the infrared nanosecond laser yields activated graphite electrodes that are conductive, non-cytotoxic and electrochemically inert. Their comprehensive assessment indicates that our laser-induced carbon electrodes are suitable for future transfer into in vivo studies, including neural recordings, stimulation and neurotransmitters detection.
Rudmann L, Alt MT, Ashouri Vajari D, Stieglitz T
Integrated optoelectronic microprobes
2018 Curr Opin Neurobiol, Band: 50, Nummer: June, Seiten: 72 - 82
KurzfassungAbstract: Optogenetics opened not only new exciting opportunities to interrogate the nervous system but also requires adequate probes to facilitate these wishes. Therefore, a multidisciplinary effort is essential to match these technical opportunities with biological needs in order to establish a stable and functional material-tissue interface. This in turn can address an optical intervention of the genetically modified, light sensitive cells in the nervous system and recording of electrical signals from single cells and neuronal networks that result in behavioral changes. In this review, we present the state of the art of optoelectronic probes and assess advantages and challenges of the different design approaches. At first, we discuss mechanisms and processes at the material-tissue interface that influence the performance of optoelectronic probes in acute and chronic implantations. We classify optoelectronic probes by their property of delivering light to the tissue: by waveguides or by integrated light sources at the sites of intervention. Both approaches are discussed with respect to size, spatial resolution, opportunity to integrate electrodes for electrical recording and potential interactions with the target tissue. At last, we assess translational aspects of the state of the art. Long-term stability of probes and the opportunity to integrate them into fully implantable, wireless systems are a prerequisite for chronic applications and a transfer from fundamental neuroscientific studies into treatment options for diseases and clinical trials. Highlights: - Miniaturization technologies enable multichannel optoelectronic neural probes. - No external laser is needed when light sources are directly integrated on the probes. - Connectors to recording equipment still limit further miniaturization. - Wireless systems with integrated multiplexers and amplifiers can replace connectors. - Longevity of probes is mandatory for chronic implantation.
Ashouri Vajari D, Vomero M, Erhardt JB, Sadr A, Ordonez JS, Coenen VA, Stieglitz T
Integrity Assessment of a Hybrid DBS Probe that Enables Neurotransmitter Detection Simultaneously to Electrical Stimulation and Recording.
2018 Micromachines, Band: 9, Nummer: 10, Seiten: 510 - 524
KurzfassungDeep brain stimulation (DBS) is a successful medical therapy for many treatment resistant neuropsychiatric disorders such as movement disorders; e.g., Parkinson’s disease, Tremor, and dystonia. Moreover, DBS is becoming more and more appealing for a rapidly growing number of patients with other neuropsychiatric diseases such as depression and obsessive compulsive disorder. In spite of the promising outcomes, the current clinical hardware used in DBS does not match the technological standards of other medical applications and as a result could possibly lead to side effects such as high energy consumption and others. By implementing more advanced DBS devices, in fact, many of these limitations could be overcome. For example, a higher channels count and smaller electrode sites could allow more focal and tailored stimulation. In addition, new materials, like carbon for example, could be incorporated into the probes to enable adaptive stimulation protocols by biosensing neurotransmitters in the brain. Updating the current clinical DBS technology adequately requires combining the most recent technological advances in the field of neural engineering. Here, a novel hybrid multimodal DBS probe with glassy carbon microelectrodes on a polyimide thin-film device assembled on a silicon rubber tubing is introduced. The glassy carbon interface enables neurotransmitter detection using fast scan cyclic voltammetry and electrophysiological recordings while simultaneously performing electrical stimulation. Additionally, the presented DBS technology shows no imaging artefacts in magnetic resonance imaging. Thus, we present a promising new tool that might lead to a better fundamental understanding of the underlying mechanism of DBS while simultaneously paving our way towards better treatments.
da Costa CA, Pasluosta CF, Eskofier B, da Silva DB, da Rosa Righi R
Internet of Health Things: Toward intelligent vital signs monitoring in hospital wards.
2018 Artif Intell Med
KurzfassungBackground Large amounts of patient data are routinely manually collected in hospitals by using standalone medical devices, including vital signs. Such data is sometimes stored in spreadsheets, not forming part of patients’ electronic health records, and is therefore difficult for caregivers to combine and analyze. One possible solution to overcome these limitations is the interconnection of medical devices via the Internet using a distributed platform, namely the Internet of Things. This approach allows data from different sources to be combined in order to better diagnose patient health status and identify possible anticipatory actions. Methods This work introduces the concept of the Internet of Health Things (IoHT), focusing on surveying the different approaches that could be applied to gather and combine data on vital signs in hospitals. Common heuristic approaches are considered, such as weighted early warning scoring systems, and the possibility of employing intelligent algorithms is analyzed. Results As a result, this article proposes possible directions for combining patient data in hospital wards to improve efficiency, allow the optimization of resources, and minimize patient health deterioration. Conclusion It is concluded that a patient-centered approach is critical, and that the IoHT paradigm will continue to provide more optimal solutions for patient management in hospital wards. Graphical abstract Download high-res image (133KB)Download full-size image
Fiath R, Hofer KT, Csikos V, Horvath D, Nanasi T, Toth K, Pothof F, Bohler C, Asplund M, Ruther P, Ulbert I
Long-term recording performance and biocompatibility of chronically implanted cylindrically-shaped, polymer-based neural interfaces.
2018 Biomedizinische Technik/Biomedical Engineering
KurzfassungStereo-electroencephalography depth electrodes, regularly implanted into drug-resistant patients with focal epilepsy to localize the epileptic focus, have a low channel count (6-12 macro- or microelectrodes), limited spatial resolution (0.5-1 cm) and large contact area of the recording sites (~mm2). Thus, they are not suited for high-density local field potential and multiunit recordings. In this paper, we evaluated the long-term electrophysiological recording performance and histocompatibility of a neural interface consisting of 32 microelectrodes providing a physical shape similar to clinical devices. The cylindrically-shaped depth probes made of polyimide (PI) were chronically implanted for 13 weeks into the brain of rats, while cortical or thalamic activity (local field potentials, single-unit and multi-unit activity) was recorded regularly to monitor the temporal change of several features of the electrophysiological performance. To examine the tissue reaction around the probe, neuron-selective and astroglia-selective immunostaining methods were applied. Stable single-unit and multi-unit activity were recorded for several weeks with the implanted depth probes and a weak or moderate tissue reaction was found around the probe track. Our data on biocompatibility presented here and in vivo experiments in non-human primates provide a strong indication that this type of neural probe can be applied in stereo-electroencephalography recordings of up to 2 weeks in humans targeting the localization of epileptic foci providing an increased spatial resolution and the ability to monitor local field potentials and neuronal spiking activity.
Pasluosta C, Hannink J, Gassner H, Von Tscharner V, Winkler J, Klucken J, Eskofier BM
Motor output complexity in Parkinson's disease during quiet standing and walking: Analysis of short-term correlations using the entropic half-life.
2018 Hum Movement Sci, Band: 58, Seiten: 185 - 194
KurzfassungParkinson's disease (PD) is associated with alterations in motor outputs such as center of pressure (CoP) adjustments during quiet standing and foot kinematics during walking. Previous research suggests that the complexity of motor outputs reflects the number of control processes stabilizing a specific movement, providing a measure that is linked to the neurological control of the movement. The Entropic Half Life (EnHL) represents a new method for assessing motor output complexity. We hypothesized that there will be a lack of neuromuscular control pathways for PD patients, resulting in a decrease in motor output complexity. We computed the EnHL of CoP adjustments during quiet standing and foot kinematics during walking of 70 PD patients and 33 age-matched controls. Patients with PD showed longer EnHL values compared to controls, suggesting a tighter motor control. Excluding vision led to a decrease of EnHL of CoP in both groups. EnHL was correlated with spatio-temporal gait parameters. We compared EnHL with the pull test and the timed up-and-go test. No significant differences were present in the pull test, yet motor output complexity was correlated with the timed up-and-go test. The results suggest a reduced complexity in motor outputs of PD patients affecting distinct motor functions.
Rognini G, Petrini FM, Raspopovic S, Valle G, Granata G, Strauss I, Solca M, Bello-Ruiz J, Herbelin B, Mange R, D'Anna E, Di Iorio R, Di Pino G, Andreu D, Guiraud D, Stieglitz T, Rossini PM, Serino A, Micera S, Blanke O
Multisensory bionic limb to achieve prosthesis embodiment and reduce distorted phantom limb perceptions.
2018 J Neurol Neurosur Ps
de la Oliva N, Mueller M, Stieglitz T, Navarro X, Del Valle J
On the use of Parylene C polymer as substrate for peripheral nerve electrodes.
2018 Sci Rep-uk, Band: 8, Nummer: 1, Seiten: 5965 - 5965
Pasluosta C, Kiele P, Stieglitz T
Paradigms for restoration of somatosensory feedback via stimulation of the peripheral nervous system.
2018 Clin Neurophysiol, Band: 129, Nummer: 4, Seiten: 851 - 862
KurzfassungThe somatosensory system contributes substantially to the integration of multiple sensor modalities into perception. Tactile sensations, proprioception and even temperature perception are integrated to perceive embodiment of our limbs. Damage of somatosensory networks can severely affect the execution of daily life activities. Peripheral injuries are optimally corrected via direct interfacing of the peripheral nerves. Recent advances in implantable devices, stimulation paradigms, and biomimetic sensors enabled the restoration of natural sensations after amputation of the limb. The refinement of stimulation patterns to deliver natural feedback that can be interpreted intuitively such to prescind from long-learning sessions is crucial to function restoration. For this review, we collected state-of-the-art knowledge on the evolution of stimulation paradigms from single fiber stimulation to the eliciting of multisensory sensations. Data from the literature are structured into six sections: (a) physiology of the somatosensory system; (b) stimulation of single fibers; (c) restoral of multisensory percepts; (d) closure of the control loop in hand prostheses; (e) sensory restoration and the sense of embodiment, and (f) methodologies to assess stimulation outcomes. Full functional recovery demands further research on multisensory integration and brain plasticity, which will bring new paradigms for intuitive sensory feedback in the next generation of limb prostheses.
Granata G, Di Iorio R, Romanello R, Iodice F, Raspopovic S, Petrini F, Strauss I, Valle G, Stieglitz T, Cvancara P, Andreu D, Divoux JL, Giraud D, Wauters L, Hiairrassary A, Jensen W, Micera S, Rossini PM
Phantom somatosensory evoked potentials following selective intraneural electrical stimulation in two amputees.
2018 Clin Neurophysiol, Band: 129, Nummer: 6, Seiten: 1117 - 1120
KurzfassungObjective The aim of the paper is to objectively demonstrate that amputees implanted with intraneural interfaces are truly able to feel a sensation in the phantom hand by recording “phantom” somatosensory evoked potentials from the corresponding brain areas. Methods We implanted four transverse intrafascicular multichannel electrodes, available with percutaneous connections to a multichannel electrical stimulator, in the median and ulnar nerves of two left trans-radial amputees. Two channels of the implants that were able to elicit sensations during intraneural nerve stimulation were chosen, in both patients, for recording somatosensory evoked potentials. Results We recorded reproducible evoked responses by stimulating the median and the ulnar nerves in both cases. Latencies were in accordance with the arrival of somatosensory information to the primary somatosensory cortex. Conclusion Our results provide evidence that sensations generated by intraneural stimulation are truly perceived by amputees and located in the phantom hand. Moreover, our results strongly suggest that sensations perceived in different parts of the phantom hand result in different evoked responses. Significance Somatosensory evoked potentials obtained by selective intraneural electrical stimulation in amputee patients are a useful tool to provide an objective demonstration of somatosensory feedback in new generation bidirectional prostheses.
Kluge F, Hannink J, Pasluosta C, Klucken J, Gassner H, Gelse K, Eskofier BM, Krinner S
Pre-operative sensor-based gait parameters predict functional outcome after total knee arthroplasty.
2018 Gait Posture, Band: 66, Seiten: 194 - 200
KurzfassungBackground Despite the general success of total knee arthroplasty (TKA) regarding patient-reported outcome measures, studies investigating gait function have shown diverse functional outcomes. Mobile sensor-based systems have recently been employed for accurate clinical gait assessments, as they allow a better integration of gait analysis into clinical routines as compared to laboratory based systems. Research question In this study, we sought to examine whether an accurate assessment of gait function of knee osteoarthritis patients with respect to surgery outcome evaluation after TKA using a mobile sensor-based gait analysis system is possible. Methods A foot-worn sensor-based system was used to assess spatio-temporal gait parameters of 24 knee osteoarthritis patients one day before and one year after TKA, and in comparison to matched control participants. Patients were clustered into positive and negative responder groups using a heuristic approach regarding improvements in gait function. Machine learning was used to predict surgery outcome based on pre-operative gait parameters. Results Gait function differed significantly between controls and patients. Patient-reported outcome measures improved significantly after surgery, but no significant global gait parameter difference was observed between pre- and post-operative status. However, the responder groups could be correctly predicted with an accuracy of up to 89% using pre-operative gait parameters. Patients exhibiting high pre-operative gait function were more likely to experience a functional decrease after surgery. Important gait parameters for the discrimination were stride time and stride length. Significance The early identification of post-surgical functional outcomes of patients is of great importance to better inform patients pre-operatively regarding surgery success and to improve post-surgical management.
Erhardt J, Fuhrer E, Gruschke OG, Leupold J, Wapler MC, Hennig J, Stieglitz T, Korvink JG
Should patients with brain implants undergo MRI?
2018 J Neural Eng
KurzfassungPatients suffering from neuronal degenerative diseases are increasingly being equipped with neural implants to treat symptoms or restore functions and increase their quality of life. Magnetic resonance imaging (MRI) would be the modality of choice for diagnosis and compulsory post-operative monitoring of such patients. However, interactions between the MR environment and implants pose severe health risks to the patient. Nevertheless, neural implant recipients regularly underwent MRI examinations, and adverse events were reported rarely. This should not imply that the procedures are safe. More than 300.000 cochlear implant recipients are excluded from MRI unless the indication outweighs excruciating pain. For 75.000 DBS recipients quite the opposite holds: MRI is considered essential part of the implantation procedure and some medical centres deliberately exceed safety regulations which they referred to as crucially impractical. MRI related permanent neurological dysfunctions in DBS recipients have occurred in the past when manufacturer recommendations were exceeded. Within the last decades extensive effort has been invested to identify, characterise, and quantify the occurring interactions. Today we are far from a satisfying solution to achieve a safe and beneficial MR procedure for all implant recipients. To contribute, we intend to raise awareness of a growing concern and want to summon the community to stop absurdities and instead improve the situation for the increasing number of patients. Therefore, we review implant safety in the MRI literature from an engineering point of view, with a focus on cochlear and DBS implants as success stories in clinical practice. We briefly explain fundamental phenomena which can lead to patient harm, and point out breakthroughs and errors made. We end with conclusions and strategies to avoid future implants from being contraindicated to MR examinations. We believe that implant recipients should enter MRI, but before doing so, we should make sure that the procedure is reasonable.
Petrini FM, Valle G, Strauss I, Granata G, Di Iorio R, D'Anna E, Cvancara P, Mueller M, Carpaneto J, Clemente F, Controzzi M, Bisoni L, Carboni C, Barbaro M, Iodice F, Andreu D, Hiairrassary A, Divoux JL, Cipriani C, Guiraud D, Raffo L, Fernandez E, Stieglitz T, Raspopovic S, Rossini PM, Micera S
Six-Month Assessment of a Hand Prosthesis with Intraneural Tactile Feedback.
2018 Ann Neurol
KurzfassungObjective Hand amputation is a highly disabling event, which significantly affects quality of life. An effective hand replacement can be achieved if the user, in addition to motor functions, is provided with the sensations that are naturally perceived while grasping and moving. Intraneural peripheral electrodes have shown promising results toward the restoration of the sense of touch. However, the long‐term usability and clinical relevance of intraneural sensory feedback have not yet been clearly demonstrated. Methods To this aim, we performed a 6‐month clinical study with 3 transradial amputees who received implants of transverse intrafascicular multichannel electrodes (TIMEs) in their median and ulnar nerves. After calibration, electrical stimulation was delivered through the TIMEs connected to artificial sensors in the digits of a prosthesis to generate sensory feedback, which was then used by the subjects while performing different grasping tasks. Results All subjects, notwithstanding their important clinical differences, reported stimulation‐induced sensations from the phantom hand for the whole duration of the trial. They also successfully integrated the sensory feedback into their motor control strategies while performing experimental tests simulating tasks of real life (with and without the support of vision). Finally, they reported a decrement of their phantom limb pain and a general improvement in mood state. Interpretation The promising results achieved with all subjects show the feasibility of the use of intraneural stimulation in clinical settings. Ann Neurol 2018; 1–18
Bockhorst T, Pieper F, Engler G, Stieglitz T, Galindo-Leon E, Engel AK
Synchrony surfacing: Epicortical recording of correlated action potentials.
2018 Eur J Neurosci, Band: 48, Nummer: 12, Seiten: 3583 - 3596
KurzfassungSynchronous spiking of multiple neurons is a key phenomenon in normal brain function and pathologies. Recently, approaches to record spikes from the intact cortical surface using small high-density arrays of microelectrodes have been reported. It remained unaddressed how epicortical spiking relates to intracortical unit activity. We introduced a mesoscale approach using an array of 64 electrodes with intermediate diameter (250 μm) and combined large-coverage epicortical recordings in ferrets with intracortical recordings via laminar probes. Empirical data and modelling strongly suggest that our epicortical electrodes selectively captured synchronized spiking of neurons in the cortex beneath. As a result, responses to sensory stimulation were more robust and less noisy compared to intracortical activity, and receptive field properties were well preserved in epicortical recordings. This should promote insights into assembly-coding beyond the informative value of subdural EEG or single-unit spiking, and be advantageous to real-time applications in brain-machine interfacing.
Castellini C, Kõiva R, Pasluosta C, Viegas C, Eskofier BM
Tactile Myography: An Off-Line Assessment of Able-Bodied Subjects and One Upper-Limb Amputee
2018 Technologies, Band: 66, Nummer: 2
KurzfassungHuman-machine interfaces to control prosthetic devices still suffer from scarce dexterity and low reliability; for this reason, the community of assistive robotics is exploring novel solutions to the problem of myocontrol. In this work, we present experimental results pointing in the direction that one such method, namely Tactile Myography (TMG), can improve the situation. In particular, we use a shape-conformable high-resolution tactile bracelet wrapped around the forearm/residual limb to discriminate several wrist and finger activations performed by able-bodied subjects and a trans-radial amputee. Several combinations of features/classifiers were tested to discriminate among the activations. The balanced accuracy obtained by the best classifier/feature combination was on average 89.15% (able-bodied subjects) and 88.72% (amputated subject); when considering wrist activations only, the results were on average 98.44% for the able-bodied subjects and 98.72% for the amputee. The results obtained from the amputee were comparable to those obtained by the able-bodied subjects. This suggests that TMG is a viable technique for myoprosthetic control, either as a replacement of or as a companion to traditional surface electromyography.

2017

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Lachner-Piza D, Epitashvili N, Schulze-Bonhage A, Stieglitz T, Jacobs J, Dümpelmann M
A single channel sleep-spindle detector based on multivariate classification of EEG epochs: MUSSDET.
2017 J Neurosci Meth
KurzfassungBackground Studies on sleep-spindles are typically based on visual-marks performed by experts, however this process is time consuming and presents a low inter-expert agreement, causing the data to be limited in quantity and prone to bias. An automatic detector would tackle these issues by generating large amounts of objectively marked data. New Method Our goal was to develop a sensitive, precise and robust sleep-spindle detection method. Emphasis has been placed on achieving a consistent performance across heterogeneous recordings and without the need for further parameter fine tuning. The developed detector runs on a single channel and is based on multivariate classification using a support vector machine. Scalp-electroencephalogram recordings were segmented into epochs which were then characterized by a selection of relevant and non-redundant features. The training and validation data came from the Medical Center-University of Freiburg, the test data consisted of 27 records coming from 2 public databases. Results Using a sample based assessment, 53% sensitivity, 37% precision and 96% specificity was achieved on the DREAMS database. On the MASS database, 77% sensitivity, 46% precision and 96% specificity was achieved. The developed detector performed favorably when compared to previous detectors. The classification of normalized EEG epochs in a multidimensional space, as well as the use of a validation set, allowed to objectively define a single detection threshold for all databases and participants. Conclusions The use of the developed tool will allow increasing the data-size and statistical significance of research studies on the role of sleep-spindles.
Boehler C, Kleber C, Martini N, Xie Y, Dryg I, Stieglitz T, Hofmann UG, Asplund M
Actively controlled release of Dexamethasone from neural microelectrodes in a chronic in vivo study.
2017 Biomaterials, Band: 129, Seiten: 176 - 187
KurzfassungStable interconnection to neurons in vivo over long time-periods is critical for the success of future advanced neuroelectronic applications. The inevitable foreign body reaction towards implanted materials challenges the stability and an active intervention strategy would be desirable to treat inflammation locally. Here, we investigate whether controlled release of the anti-inflammatory drug Dexamethasone from flexible neural microelectrodes in the rat hippocampus has an impact on probe-tissue integration over 12 weeks of implantation. The drug was stored in a conducting polymer coating (PEDOT/Dex), selectively deposited on the electrode sites of neural probes, and released on weekly basis by applying a cyclic voltammetry signal in three electrode configuration in fully awake animals. Dex-functionalized probes provided stable recordings and impedance characteristics over the entire chronic study. Histological evaluation after 12 weeks of implantation revealed an overall low degree of inflammation around all flexible probes whereas electrodes exposed to active drug release protocols did have neurons closer to the electrode sites compared to controls. The combination of flexible probe technology with anti-inflammatory coatings accordingly offers a promising approach for enabling long-term stable neural interfaces.

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Pasluosta C, Steib S, Klamroth S, Gassner H, Hannink J, von Tscharner V, Pfeifer K, Winkler J, Klucken J, Eskofier B M
Acute Neuromuscular Adaptations in the Postural Control of Patients with Parkinson’s disease after Perturbed Walking
2017 Front Aging Neurosci, Band: 9, Nummer: 316, Seiten: 1 - 8
KurzfassungPatients suffering from Parkinson's disease (PD) present motor impairments reflected in the dynamics of the center of pressure (CoP) adjustments during quiet standing. One method to study the dynamics of CoP adjustments is the entropic half-life (EnHL), which measures the short-term correlations of a time series at different time scales. Changes in the EnHL of CoP time series suggest neuromuscular adaptations in the control of posture. In this study, we sought to investigate the immediate changes in the EnHL of CoP adjustments of patients with PD during one session of perturbed (experimental group) and unperturbed treadmill walking (control group). A total of 39 patients with PD participated in this study. The experimental group (n = 19) walked on a treadmill providing small tilting of the treadmill platform. The control group (n = 20) walked without perturbations. Each participant performed 5-min practice followed by three 5-min training blocks of walking with or without perturbation (with 3-min resting in between). Quiet standing CoP data was collected for 30 s at pre-training, after each training block, immediately post-training, and after 10 min retention. The EnHL was computed on the original and surrogates (phase-randomized) CoP signals in the medio-lateral (ML) and anterior-posterior (AP) directions. Data was analyzed using four-way mixed ANOVA. Increased EnHL values were observed for both groups (Time effect, p < 0.001) as the intervention progressed, suggesting neuromuscular adaptations in the control of posture. The EnHL of surrogate signals were significantly lower than for original signals (p < 0.001), confirming that these adaptations come from non-random control processes. There was no Group effect (p = 0.622), however by analyzing the significant Group by Direction by Time interaction (p < 0.05), a more pronounced effect in the ML direction of the perturbed group was observed. Altogether, our findings show that treadmill walking decreases the complexity of CoP adjustments, suggesting neuromuscular adaptations in balance control during a short training period. Further investigations are required to assess these adaptations during longer training intervals.
Clarke C, Rieger R, Schuettler M, Donaldson N, Taylor J
An implantable ENG detector with in-system velocity selective recording (VSR) capability.
2017 Med Biol Eng Comput, Band: 55, Nummer: 6, Seiten: 885 - 895
KurzfassungDetection and classification of electroneurogram (ENG) signals in the peripheral nervous system can be achieved by velocity selective recording (VSR) using multi-electrode arrays. This paper describes an implantable VSR-based ENG recording system representing a significant development in the field since it is the first system of its type that can record naturally evoked ENG and be interfaced wirelessly using a low data rate transcutaneous link. The system consists of two CMOS ASICs one of which is placed close to the multi-electrode cuff array (MEC), whilst the other is mounted close to the wireless link. The digital ASIC provides the signal processing required to detect selectively ENG signals based on velocity. The design makes use of an original architecture that is suitable for implantation and reduces the required data rate for transmission to units placed outside the body. Complete measured electrical data from samples of the ASICs are presented that show that the system has the capability to record signals of amplitude as low as 0.5 μV, which is adequate for the recording of naturally evoked ENG. In addition, measurements of electrically evoked ENG from the explanted sciatic nerves of Xenopus Laevis frogs are presented.
Kleber C, Bruns M, Lienkamp K, Ruhe J, Asplund M
An interpenetrating, microstructurable and covalently attached conducting polymer hydrogel for neural interfaces.
2017 Acta Biomater, Band: 58, Seiten: 365 - 375
KurzfassungThis study presents a new conducting polymer hydrogel (CPH) system, consisting of the synthetic hydrogel P(DMAA-co-5%MABP-co-2,5%SSNa) and the conducting polymer (CP) poly(3,4-ethylenedioxythiophene) (PEDOT), intended as coating material for neural interfaces. The composite material can be covalently attached to the surface electrode, can be patterned by a photolithographic process to influence selected electrode sites only and forms an interpenetrating network. The hybrid material was characterized using cyclic voltammetry (CV), impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS), which confirmed a homogeneous distribution of PEDOT throughout all CPH layers. The CPH exhibited a 2,5 times higher charge storage capacity (CSC) and a reduced impedance when compared to the bare hydrogel. Electrochemical stability was proven over at least 1000 redox cycles. Non-toxicity was confirmed using an elution toxicity test together with a neuroblastoma cell-line. The described material shows great promise for surface modification of neural probes making it possible to combine the beneficial properties of the hydrogel with the excellent electronic properties necessary for high quality neural microelectrodes. STATEMENT OF SIGNIFICANCE: Conductive polymer hydrogels have emerged as a promising new class of materials to functionalize electrode surfaces for enhanced neural interfaces and drug delivery. Common weaknesses of such systems are delamination from the connection surface, and the lack of suitable patterning methods for confining the gel to the selected electrode site. Various studies have reported on conductive polymer hydrogels addressing one of these challenges. In this study we present a new composite material which offers, for the first time, the unique combination of properties: it can be covalently attached to the substrate, forms an interpenetrating network, shows excellent electrical properties and can be patterned via UV-irradiation through a structured mask.

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Kohler F, Gkogkidis A, Bentler C, Wang X, Gierthmuehlen M, Fischer J, Stolle C, Reindl L, Rickert J, Stieglitz T, Ball T, Schuettler M
Closed-loop interaction with the cerebral cortex: a review of wireless implant technology
2017 Brain-Computer Interfaces, Band: 4, Nummer: 3, Seiten: 146 - 154
KurzfassungWireless implants for interaction with the cortex have developed rapidly over the last decade and increasingly meet demands of clinical brain–computer interfaces. For such applications, well-established technologies are available, suitable for recording of neural activity at different spatial scales and adequate for modulating brain activity by cortical electrical stimulation. The incorporation of recording and stimulation into closed-loop systems is a major aim in active, fully implantable medical device design. To reduce clinical long-term implantation risk and to increase the spatial specificity of epicortical recordings and stimulation, micro-electrocorticography is a promising technology. However, currently there is a lack of implants suitable for chronic human clinical applications that utilize micro-electrocorticography and possess closed-loop functionality. Here, we describe the clinical importance of cortical stimulation, give an overview of existing implants that use mainly epicortical recording methods, and present results of a closed-loop micro-electrocorticography system developed for clinical application within a collaborative framework. Finally, we conclude with our vision of future design options in the field of neuroprosthetic devices.

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Stitt I, Hollensteiner KJ, Galindo-Leon E, Pieper F, Fiedler E, Stieglitz T, Engler G, Nolte G, Engel AK
Dynamic reconfiguration of cortical functional connectivity across brain states.
2017 Sci Rep-uk, Band: 7, Nummer: 1, Seiten: 8797 - 8797
KurzfassungThroughout each day, the brain displays transient changes in state, as evidenced by shifts in behavior and vigilance. While the electrophysiological correlates of brain states have been studied for some time, it remains unclear how large-scale cortico-cortical functional connectivity systematically reconfigures across states. Here, we investigate state-dependent shifts in cortical functional connectivity by recording local field potentials (LFPs) during spontaneous behavioral transitions in the ferret using chronically implanted micro-electrocorticographic (µECoG) arrays positioned over occipital, parietal, and temporal cortical regions. To objectively classify brain state, we describe a data-driven approach that projects time-varying LFP spectral properties into brain state space. Distinct brain states displayed markedly different patterns of cross-frequency phase-amplitude coupling and inter-electrode phase synchronization across several LFP frequency bands. The largest across-state differences in functional connectivity were observed between periods of presumed slow-wave and rapid-eye-movement-sleep/active-state, which were characterized by the contrasting phenomena of cortical network fragmentation and global synchronization, respectively. Collectively, our data provide strong evidence that large-scale functional interactions in the brain dynamically reconfigure across behavioral states.
Kautz T, Eskofier B, Pasluosta C
Generic performance measure for multiclass-classifiers
2017 Pattern Recogn, Band: 68, Nummer: Aug, Seiten: 111 - 125
KurzfassungThe evaluation of classification performance is crucial for algorithm and model selection. However, a performance measure for multiclass classification problems (i.e., more than two classes) has not yet been fully adopted in the pattern recognition and machine learning community. In this work, we introduce the multiclass performance score (MPS), a generic performance measure for multiclass problems. The MPS was designed to evaluate any multiclass classification algorithm for any arbitrary testing condition. This measure handles the case of unknown misclassification costs and imbalanced data, and provides confidence indicators of the performance estimation. We evaluated the MPS using real and synthetic data, and compared it against other frequently used performance measures. The results suggest that the proposed MPS allows capturing the performance of a classification with minimum influence from the training and testing conditions. This is demonstrated by its robustness towards imbalanced data and its sensitivity towards class separation in feature space.

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Zijlmans M, Worrell GA, Dumpelmann M, Stieglitz T, Barborica A, Heers M, Ikeda A, Usui N, Le Van Quyen M
How to record high-frequency oscillations in epilepsy: A practical guideline.
2017 Epilepsia
KurzfassungOBJECTIVE: Technology for localizing epileptogenic brain regions plays a central role in surgical planning. Recent improvements in acquisition and electrode technology have revealed that high-frequency oscillations (HFOs) within the 80-500 Hz frequency range provide the neurophysiologist with new information about the extent of the epileptogenic tissue in addition to ictal and interictal lower frequency events. Nevertheless, two decades after their discovery there remain questions about HFOs as biomarkers of epileptogenic brain and there use in clinical practice. METHODS: In this review, we provide practical, technical guidance for epileptologists and clinical researchers on recording, evaluation, and interpretation of ripples, fast ripples, and very high-frequency oscillations. RESULTS: We emphasize the importance of low noise recording to minimize artifacts. HFO analysis, either visual or with automatic detection methods, of high fidelity recordings can still be challenging because of various artifacts including muscle, movement, and filtering. Magnetoencephalography and intracranial electroencephalography (iEEG) recordings are subject to the same artifacts. SIGNIFICANCE: High-frequency oscillations are promising new biomarkers in epilepsy. This review provides interested researchers and clinicians with a review of current state of the art of recording and identification and potential challenges to clinical translation.

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Garai P, Koh RGL, Schuettler M, Stieglitz T, Zariffa J
Influence of Anatomical Detail and Tissue Conductivity Variations in Simulations of Multi-Contact Nerve Cuff Recordings.
2017 Ieee T Neur Sys Reh, Band: 25, Nummer: 9, Seiten: 1653 - 1662
KurzfassungAccurate simulations of peripheral nerve recordings are needed to develop improved neuroprostheses. Previous models of peripheral nerves contained simplifications whose effects have not been investigated. We created a novel detailed finite element (FE) model of a peripheral nerve, and used it to carry out a sensitivity analysis of several model parameters. To construct the model, in vivo recordings were obtained in a rat sciatic nerve using an 8-channel nerve cuff electrode, after which the nerve was imaged using magnetic resonance imaging (MRI). The FE model was constructed based on the MRI data, and included progressive branching of the fascicles. Neural pathways were defined in the model for the tibial, peroneal and sural fascicles. The locations of these pathways were selected so as to maximize the correlations between the simulated and in vivo recordings. The sensitivity analysis showed that varying the conductivities of neural tissues had little influence on the ability of the model to reproduce the recording patterns obtained experimentally. On the other hand, the increased anatomical detail did substantially alter the recording patterns observed, demonstrating that incorporating fascicular branching is an important consideration in models of nerve cuff recordings. The model used in this study constitutes an improved simulation tool and can be used in the design of neural interfaces.
Behkami S, Frounchi J, Ghaderi Pakdel F, Stieglitz T
Investigations on effects of the hole size to fix electrodes and interconnection lines in polydimethylsiloxane
2017 J Micromech Microeng, Band: 27, Nummer: 11
KurzfassungTranslational research in bioelectronics medicine and neural implants often relies on established material assemblies made of silicone rubber (polydimethylsiloxane-PDMS) and precious metals. Longevity of the compound is of utmost importance for implantable devices in therapeutic and rehabilitation applications. Therefore, secure mechanical fixation can be used in addition to chemical bonding mechanisms to interlock PDMS substrate and insulation layers with metal sheets for interconnection lines and electrodes. One of the best ways to fix metal lines and electrodes in PDMS is to design holes in electrode rims to allow for direct interconnection between top to bottom layer silicone. Hence, the best layouts and sizes of holes (up to 6) which provide sufficient stability against lateral and vertical forces have been investigated with a variety of numbers of hole in line electrodes, which are simulated and fabricated with different layouts, sizes and materials. Best stability was obtained with radii of 100, 72 and 62 μm, respectively, and a single central hole in aluminum, platinum and MP35N foil line electrodes of 400 × 500 μm² size and of thickness 20 μm. The study showed that the best hole size which provides line electrode immobility (of thickness less than 30 μm) within a central hole is proportional to reverse value of Young's Modulus of the material used. Thus, an array of line electrodes was designed and fabricated to study this effect. Experimental results were compared with simulation data. Subsequently, an approximation curve was generated as design rule to propose the best radius to fix line electrodes according to the material thickness between 10 and 200 μm using PDMS as substrate material.

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Hannink J, Kautz T, Pasluosta C, Barth J, Schulein S, Gassmann KG, Klucken J, Eskofier B
Mobile Stride Length Estimation with Deep Convolutional Neural Networks.
2017 Ieee J Biomed Health
Steib S, Klamroth S, Gassner H, Pasluosta C, Eskofier B, Winkler J, Klucken J, Pfeifer K
Perturbation During Treadmill Training Improves Dynamic Balance and Gait in Parkinson's Disease: A Single-Blind Randomized Controlled Pilot Trial.
2017 Neurorehab Neural Re, Band: 31, Nummer: 8, Seiten: 758 - 768
KurzfassungBACKGROUND: Gait and balance dysfunction are major symptoms in Parkinson's disease (PD). Treadmill training improves gait characteristics in this population but does not reflect the dynamic nature of controlling balance during ambulation in everyday life contexts. OBJECTIVE: To evaluate whether postural perturbations during treadmill walking lead to superior effects on gait and balance performance compared with standard treadmill training. METHODS: In this single-blind randomized controlled trial, 43 PD patients (Hoehn & Yahr stage 1-3.5) were assigned to either an 8-week perturbed treadmill intervention (n = 21) or a control group (n = 22) training on the identical treadmill without perturbations. Patients were assessed at baseline, postintervention, and at 3 months' follow-up. Primary endpoints were overground gait speed and balance (Mini-BESTest). Secondary outcomes included fast gait speed, walking capacity (2-Minute Walk Test), dynamic balance (Timed Up-and-Go), static balance (postural sway), and balance confidence (Activities-Specific Balance Confidence [ABC] scale). RESULTS: There were no significant between-group differences in change over time for the primary outcomes. At postintervention, both groups demonstrated similar improvements in overground gait speed ( P = .009), and no changes in the Mini-BESTest ( P = .641). A significant group-by-time interaction ( P = .048) existed for the Timed Up-and-Go, with improved performance only in the perturbation group. In addition, the perturbation but not the control group significantly increased walking capacity ( P = .038). Intervention effects were not sustained at follow-up. CONCLUSIONS: Our primary findings suggest no superior effect of perturbation training on gait and balance in PD patients. However, some favorable trends existed for secondary gait and dynamic balance parameters, which should be investigated in future trials.
Erhardt JB, Koenig K, Leupold J, Pasluosta C, Stieglitz T
Precise localization of silicone-based intercranial planar electrodes in magnetic resonance imaging.
2017 Conf Proc IEEE Eng Med Biol Soc, Band: 2017, Seiten: 513 - 516
KurzfassungIntercranial planar electrodes enable neural recordings with high spatial resolution in diagnosis as well as for treatments. The value of the measurements increases with the precision of localization of the electrodes related to the individual anatomy. In this context, post-implantation MRI provides excellent soft tissue contrast, but the accurate localization of electrodes is impaired by magnetic susceptibility artifacts. We have addressed this problem without adding a substantial burden to the electrode fabrication process. Simple silicone reference structures were strategically placed on the implant surface to visualize the electrodes position in MRI. These reference structures allowed high precision electrode localization independently of electrode imaging artifacts. This implant manufacturing approach could prove extremely useful in combination with existing image processin
Mueller M, de la Oliva N, Del Valle J, Delgado-Martinez I, Navarro X, Stieglitz T
Rapid prototyping of flexible intrafascicular electrode arrays by picosecond laser structuring.
2017 J Neural Eng, Band: 14, Nummer: 6, Seiten: 066016 - 066016
KurzfassungInterfacing the peripheral nervous system can be performed with a large variety of electrode arrays. However, stimulating and recording a nerve while having a reasonable amount of channels limits the number of available systems. Translational research towards human clinical trial requires device safety and biocompatibility but would benefit from design flexibility in the development process to individualize probes. APPROACH: We selected established medical grade implant materials like precious metals and Parylene C to develop a rapid prototyping process for novel intrafascicular electrode arrays using a picosecond laser structuring. A design for a rodent animal model was developed in conjunction with an intrafascicular implantation strategy. Electrode characterization and optimization was performed first in saline solution in vitro before performance and biocompatibility were validated in sciatic nerves of rats in chronic implantation. MAIN RESULTS: The novel fabrication process proved to be suitable for prototyping and building intrafascicular electrode arrays. Electrochemical properties of the electrode sites were enhanced and tested for long-term stability. Chronic implantation in the sciatic nerve of rats showed good biocompatibility, selectivity and stable stimulation thresholds. SIGNIFICANCE: Established medical grade materials can be used for intrafascicular nerve electrode arrays when laser structuring defines structure size in the micro-scale. Design flexibility reduces re-design cycle time and material certificates are beneficial support for safety studies on the way to clinical trials.
Krahenbuhl SM, Cvancara P, Stieglitz T, Bonvin R, Michetti M, Flahaut M, Durand S, Deghayli L, Applegate LA, Raffoul W
Return of the cadaver: Key role of anatomic dissection for plastic surgery resident training.
2017 Medicine, Band: 96, Nummer: 29, Seiten: e7528 - e7528
KurzfassungSuccessful Plastic Surgery Residency training is subjected to evolving society pressure of lower hourly work weeks imposed by external committees, labor laws, and increased public awareness of patient care quality. Although innovative measures for simulation training of surgery are appearing, there is also the realization that basic anatomy training should be re-enforced and cadaver dissection is of utmost importance for surgical techniques.In the development of new technology for implantable neurostimulatory electrodes for the management of phantom limb pain in amputee patients, a design of a cadaveric model has been developed with detailed steps for innovative transfascicular insertion of electrodes. Overall design for electrode and cable implantation transcutaneous was established and an operating protocol devised.Microsurgery of the nerves of the upper extremities for interfascicular electrode implantation is described for the first time. Design of electrode implantation in cadaver specimens was adapted with a trocar delivery of cables and electrodes transcutaneous and stabilization of the electrode by suturing along the nerve. In addition, the overall operating arena environment with specific positions of the multidisciplinary team necessary for implantable electrodes was elaborated to assure optimal operating conditions and procedures during the organization of a first-in-man implantation study.Overall importance of plastic surgery training for new and highly technical procedures is of importance and particularly there is a real need to continue actual cadaveric training due to patient variability for nerve anatomic structures.

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Hannink J, Kautz T, Pasluosta C, Gassmann KG, Klucken J, Eskofier B
Sensor-based Gait Parameter Extraction with Deep Convolutional Neural Networks.
2017 Ieee J Biomed Health, Band: 21, Nummer: 1, Seiten: 85 - 93
KurzfassungMeasurement of stride-related, biomechanical parameters is the common rationale for objective gait impairment scoring. State-of-the-art double-integration approaches to extract these parameters from inertial sensor data are, however, limited in their clinical applicability due to the underlying assumptions. To overcome this, we present a method to translate the abstract information provided by wearable sensors to context-related expert features based on deep convolutional neural networks. Regarding mobile gait analysis, this enables integration-free and data-driven extraction of a set of eight spatio-temporal stride parameters. To this end, two modeling approaches are compared: a combined network estimating all parameters of interest and an ensemble approach that spawns less complex networks for each parameter individually. The ensemble approach is outperforming the combined modeling in the current application. On a clinically relevant and publicly available benchmark dataset, we estimate stride length, width and medio-lateral change in foot angle up to -0.15 ± 6.09 cm, -0.09 ± 4.22 cm and 0.13 ± 3.78° respectively. Stride, swing and stance time as well as heel and toe contact times are estimated up to ±0.07, ±0.05, ±0.07, ±0.07 and ±0.12 s respectively. This is comparable to and in parts outperforming or defining state of the art. Our results further indicate that the proposed change in the methodology could substitute assumption-driven double-integration methods and enable mobile assessment of spatio-temporal stride parameters in clinically critical situations as, e.g., in the case of spastic gait impairments.
Behkami S, Frounchi J, Ghaderi Pakdel F, Stieglitz T
Simulation of effects of the electrode structure and material in the density measuring system of the peripheral nerve based on micro-electrical impedance tomography.
2017 Biomed Eng-biomed Te
KurzfassungThe electrode structure in micro-electrical impedance tomography (MEIT) highly influences the measurement sensitivity and therefore the reconstructed image quality. Hence, optimizing the electrode structure leads to the improvement of image quality in the reconstruction procedure. Although there have been many investigations on electrical impedance tomography (EIT) electrodes, there is no comprehensive study on their influence on images of the peripheral nerve. In this paper, we present a simulation method to study the effects of the electrode structure in the density measurement system of the peripheral nerve based on MEIT. The influence of the electrode structure such as dimensions, material and the number of electrodes and also the recognition feature of different radii of fascicle and different locations of fascicles has been studied. Data were reconstructed from the real and imaginary parts of complex conductivity data, respectively. It has been shown that the material of the electrodes had no effect on the reconstructed images, while the dimensions of the electrodes significantly affected the image sensitivity and thus the image quality. An increase in the number of electrodes increased the amount of data and information content. However, as the number of electrodes increased due to the given perimeter of the peripheral nerve, the area of the electrodes was reduced. This reduction affects the reconstructed image quality. The real and imaginary parts of the data were separately reconstructed for each case. Although, in real EIT systems, the reconstructed images using the real part of the signal have a better signal-to-noise ratio (SNR), this study proved that for a density measuring system of the peripheral nerve, the reconstructed images using the imaginary part of the signal had better quality. This simulation study proposes the effects of the electrode size and material and obtained spatial resolution that was high enough to reconstruct fascicles in a peripheral nerve.

2016

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Boehler C, Guder F, Kucukbayrak UM, Zacharias M, Asplund M
A Simple Approach for Molecular Controlled Release based on Atomic Layer Deposition Hybridized Organic-Inorganic Layers.
2016 Sci Rep-uk, Band: 6, Seiten: 19574 - 19574
KurzfassungAccurate simulations of peripheral nerve recordings are needed to develop improved neuroprostheses. Previous models of peripheral nerves contained simplifications whose effects have not been investigated. We created a novel detailed finite element (FE) model of a peripheral nerve, and used it to carry out a sensitivity analysis of several model parameters. To construct the model, in vivo recordings were obtained in a rat sciatic nerve using an 8-channel nerve cuff electrode, after which the nerve was imaged using magnetic resonance imaging (MRI). The FE model was constructed based on the MRI data, and included progressive branching of the fascicles. Neural pathways were defined in the model for the tibial, peroneal and sural fascicles. The locations of these pathways were selected so as to maximize the correlations between the simulated and in vivo recordings. The sensitivity analysis showed that varying the conductivities of neural tissues had little influence on the ability of the model to reproduce the recording patterns obtained experimentally. On the other hand, the increased anatomical detail did substantially alter the recording patterns observed, demonstrating that incorporating fascicular branching is an important consideration in models of nerve cuff recordings. The model used in this study constitutes an improved simulation tool and can be used in the design of neural interfaces.
Heizmann S, Kilias A, Ruther P, Egert U, Asplund M
Active Control of Dye Release for Neuronal Tracing using PEDOT-PSS Coated Electrodes.
2016 Ieee T Neur Sys Reh
Schopf A, Boehler C, Asplund M
Analytical methods to determine electrochemical factors in electrotaxis setups and their implications for experimental design.
2016 Bioelectrochemistry, Band: 109, Seiten: 41 - 48
KurzfassungDirect current (DC) stimulation can be used to influence the orientation and migratory behavior of cells and results in cellular electrotaxis. Experimental work on such phenomena commonly relies on electrochemical dissolution of silver:silver–chloride (Ag:AgCl) electrodes to provide the stimulation via salt bridges. The strong ionic flow can be expected to influence the cell culture environment. In order to shed more light on which effects that must be considered, and possibly counter balanced, we here characterize a typical DC stimulation system. Silver migration speed was determined by stripping voltammetry. pH variability with stimulation was measured by ratiometric image analysis and conductivity alterations were quantified via two electrode impedance spectroscopy. It could be concluded that pH shifts towards more acidic values, in a linear manner with applied charge, after the buffering capability of the culture medium is exceeded. In contrast, the influence on conductivity was of negligible magnitude. Silver ions could enter the culture chamber at low concentrations long before a clear effect on the viability of the cultured cells could be observed. A design rule of 1 cm salt bridge per C of stimulation charge transferred was however sufficient to ensure separation between cells and silver at all times.
Rieger SB, Pfau J, Stieglitz T, Asplund M, Ordonez JS
Concept and Development of an Electronic Framework Intended for Electrode and Surrounding Environment Characterization In Vivo.
2016 Sensors-basel, Band: 17, Nummer: 1
KurzfassungAbstract There has been substantial progress over the last decade towards miniaturizing implantable microelectrodes for use in Active Implantable Medical Devices (AIMD). Compared to the rapid development and complexity of electrode miniaturization, methods to monitor and assess functional integrity and electrical functionality of these electrodes, particularly during long term stimulation, have not progressed to the same extent. Evaluation methods that form the gold standard, such as stimulus pulse testing, cyclic voltammetry and electrochemical impedance spectroscopy, are either still bound to laboratory infrastructure (impractical for long term in vivo experiments) or deliver no comprehensive insight into the material’s behaviour. As there is a lack of cost effective and practical predictive measures to understand long term electrode behaviour in vivo, material investigations need to be performed after explantation of the electrodes. We propose the analysis of the electrode and its environment in situ, to better understand and correlate the effects leading to electrode failure. The derived knowledge shall eventually lead to improved electrode designs, increased electrode functionality and safety in clinical applications. In this paper, the concept, design and prototyping of a sensor framework used to analyse the electrode’s behaviour and to monitor diverse electrode failure mechanisms, even during stimulation pulses, is presented. We focused on the electronic circuitry and data acquisition techniques required for a conceptual multi-sensor system. Functionality of single modules and a prototype framework have been demonstrated, but further work is needed to convert the prototype system into an implantable device. In vitro studies will be conducted first to verify sensor performance and reliability.
Liljemalm R, Nyberg T
Damage criteria for cerebral cortex cells subjected to hyperthermia.
2016 Int J Hyperther, Band: 32, Nummer: 6, Seiten: 704 - 712
KurzfassungTemperatures above the normal physiological threshold may cause damage to cells and tissue. In this study, the response of a culture of dissociated cerebral cortex cells exposed to laser-induced temperature gradients was examined. The cellular response was evaluated using a fluorescent dye indicating metabolic activity. Furthermore, by using a finite element model of the heating during the pulsed laser application, threshold temperatures could be extracted for the cellular response at different laser pulse lengths. These threshold temperatures were used in an Arrhenius model to extract the kinetic parameters, i.e. the activation energy (Ea), and the frequency factor (Ac), for the system. A damage signal ratio was defined and calculated to 5% for the cells to increase their metabolism as a response to the heat. Furthermore, efficient stimulation with 20-ms long laser pulses did not evoke changes in metabolism. Thus, 20 ms could be a potential pulse length for functional stimulation of neural cells.
Piza DL, Bruder JC, Jacobs J, Schulze-Bonhage A, Stieglitz T, Dumpelmann M
Differentiation of spindle associated hippocampal HFOs based on a correlation analysis.
2016 Conf Proc IEEE Eng Med Biol Soc, Band: 2016, Seiten: 5501 - 5504
KurzfassungHigh Frequency Oscillations (HFOs) have been described as biomarkers of epileptogenic tissue; however their pathological/physiological classification poses a challenge to their predictive power. For the population of ripples co-occurring with sleep spindles, those ripples improving the antiparallel correlation of ripple-peaks and sleep spindle-troughs were classified as coupled-ripples and the rest as uncoupled-ripples. For the same population of ripples two reference groups called in-SOZ and non-SOZ were formed according to the ripples' location inside or outside the seizure onset zone (SOZ). Nine patients were analyzed and their formed groups were compared using three amplitude, three waveform and three frequency features. The coupled-ripples group showed similar feature values to the non-SOZ group. The correlation based classification approach shows potential to verify the SOZ and predict alterations in the memory consolidation process.
Plachta DT, Zentner J, Aguirre D, Cota O, Stieglitz T, Gierthmuehlen M
Effect of Cardiac-Cycle-Synchronized Selective Vagal Stimulation on Heart Rate and Blood Pressure in Rats.
2016 Adv Ther, Band: 33, Nummer: 7, Seiten: 1246 - 1261
Qiao Shaoyu, Stieglitz T, Yoshida Ken
Estimation of the Electrode-Fiber Bioelectrical Coupling From Extracellularly Recorded Single Fiber Action Potentials
2016 IEEE Transactions on Neural Systems and Rehabilitation Engineering, Band: 24, Nummer: 8, Seiten: 951 - 960
KurzfassungSelective peripheral neural interfaces are currently capable of detecting minute electrical signals from nearby nerve fibers as single fiber action potential (SFAP) waveforms. Each detected single unit has a distinct shape originating from the unique bioelectrical coupling that exists between the neuroprosthetic electrode, the nerve fiber and the extracellular milieu. The bioelectrical coupling manifests itself as a series of low-pass Bessel filters acting on the action currents along the nerve fiber. Here, we present a method to estimate the electrode-fiber bioelectrical coupling through a quantitative analysis of the spectral distribution of the single units extracellularly recorded with the thin-film longitudinal intrafascicular electrode (tfLIFE) in an in vivo mammalian peripheral nerve animal model. The bioelectrical coupling estimate is an estimate of the electrode sensitivity function traversed by the nerve fiber, suggesting that it is as a means to directly measure the spatial relationship between the nerve fiber and electrode. It not only reflects a shape change to the SFAP, but has implications for in situ nerve fiber location tracking, in situ diagnostics of nerves and neuroproshetic electrodes, and assessment of the biocompatibility of neural interfaces and the health of the reporting nerve fibers.
Gierthmuehlen M*, Stieglitz T, Zentner J, Plachta DT*
Haemodynamic Responses to Selective Vagal Nerve Stimulation under Enalapril Medication in Rats.
2016 Plos One, Band: 11, Nummer: 1, Seiten: e0147045 - e0147045
Gierthmuehlen M*, Aguirre D, Cota O, Zentner J, Stieglitz T, Plachta DT*
Influence of Clonidine on Antihypertensive Selective Afferent Vagal Nerve Stimulation in Rats.
2016 Neuromodulation, Band: 19, Nummer: 6, Seiten: 597 - 606
Hassler C, Guy J, Nietzschmann M, Plachta DT, Staiger JF, Stieglitz T
Intracortical polyimide electrodes with a bioresorbable coating.
2016 Biomed Microdevices, Band: 18, Nummer: 5, Seiten: 81 - 81
KurzfassungPolyimide based shaft electrodes were coated with a bioresorbable layer to stiffen them for intracortical insertion and to reduce the mechanical mismatch between the target tissue and the implanted device after degradation of the coating. Molten saccharose was used as coating material. In a proof-of-concept study, the electrodes were implanted into the cortex of Wistar rats and the insertion forces during implantation were recorded. Electrochemical impedance spectroscopy was performed immediately after implantation and up to 13 weeks after implantation to monitor the tissue responsetotheimplantedelectrodes.Therecordedspectrawere modeled with an equivalent circuit to differentiate the influence of the single components. In one rat, a peak in the encapsulation resistance was observable after two weeks of implantation, indicating the peak of the acute inflammatory response. In another rat, the lowest resistances were observed after four weeks, indicating the termination of the acute inflammatory response. Multiunitactivity was recorded with an adequatesignaltonoiseratiotoallowspikesorting.Histology was performed after 7, 45 and 201 days of implantation. The results showed the highest tissue reaction after 45 days and confirmed impedance data that acute inflammatory reactions terminate over time.
Cvancara P, Lauser S, Rudmann L, Stieglitz T
Investigations on different epoxies for electrical insulation of microflex structures.
2016 Conf Proc IEEE Eng Med Biol Soc, Band: 2016, Seiten: 1963 - 1966
KurzfassungThe microflex interconnection (MFI) technique is often used to connect electrically and mechanically thin film ribbons or electrodes with a solid substrate like screen printed ceramics. For stabilization reasons epoxy is used to fix the MFI structure. As epoxy tends to form cracks when surrounded by water or electrolytes we are eager to find an epoxy which provides sufficient insulation between the single channels of the MFI structure also in a moist surrounding. Therefore we designed a device to investigate the insulating properties of different epoxies (Uhu Plus Endfest 300, Epo-Tek 353ND and 353ND-T) immersed in saline solution. For comparison reasons we use as well only silicone rubber (Nusil MED-1000) instead of epoxy. We performed the experiment for 23 weeks at 60 °C, which corresponds to 26 months at body temperature. The epoxy of preference is the Epo-Tek 353ND-T as it develops no failures and insulates all channel pairs of the MFI structures electrically over the whole period of experiment.
Oliveira A, Ordonez J, Ashouri Vajari D, Eickenscheidt M, Stieglitz T
Laser-induced carbon pyrolysis of electrodes for neural interface systems
2016 European Journal of Translational Myology, Band: 26, Nummer: 3
KurzfassungThe objective of this work is to produce a laser- fabricated polymer-metal-polymer electrode with the merit of a carbon-based coating as the active site. A 10 μm-thick layer of parylene-C is used serving as the insulation layer in which the active site is locally laser-pyrolyzed. Our preliminary results show that the proposed method is promising in terms of fabrication feasibility and desired electrochemical capabilities.
Boehler C, Oberueber F, Schlabach S, Stieglitz T, Asplund M
Long-Term Stable Adhesion for Conducting Polymers in Biomedical Applications: IrOx and Nanostructured Platinum Solve the Chronic Challenge.
2016 Acs Appl Mater Inter, Seiten: 189 - 197
KurzfassungConducting polymers (CPs) have frequently been described as outstanding coating materials for neural microelectrodes, providing significantly reduced impedance or higher charge injection compared to pure metals. Usability has until now, however, been limited by poor adhesion of polymers like poly(3,4-ethylenedioxythiophene) (PEDOT) to metallic substrates, ultimately precluding long-term applications. The aim of this study was to overcome this weakness of CPs by introducing two novel adhesion improvement strategies that can easily be integrated with standard microelectrode fabrication processes. Iridium Oxide (IrOx) demonstrated exceptional stability for PEDOT coatings, resulting in polymer survival over 10 000 redox cycles and 110 days under accelerated aging conditions at 60 °C. Nanostructured Pt was furthermore introduced as a purely mechanical adhesion promoter providing 10-fold adhesion improvement compared to smooth Pt substrates by simply altering the morphology of Pt. This layer can be realized in a very simple process that is compatible with any electrode design, turning nanostructured Pt into a universal adhesion layer for CP coatings. By the introduction of these adhesion-promoting strategies, the weakness of CP-based neural probes can ultimately be eliminated and true long-term stable use of PEDOT on neural probes will be possible in future electrode generations.
Stieglitz T, Rudmann L, Ordonez J S
Mikrosysteme ins Auge gefasst
2016 Physik Journal, Band: 15, Nummer: 5, Seiten: 33 - 38
KurzfassungDie Möglichkeit, komplexe elektronische Systeme zu miniaturisieren, hat in der Augenheilkunde zu neuartigen Verfahren geführt. So ist es möglich, den Augeninnendruck kontinuierlich zu messen oder biochemische Daten wie den Blutzucker zu ermitteln. Die technische, elektrische Stimulation von Zellen der Netzhaut erlaubt es, eine Erblindung zu vermeiden oder ein beschränktes Maß an Sehvermögen wiederherzustellen. Allerdings sind die Herausforderungen an Materialien und Fertigungstechniken für Medizinprodukte am und im Auge sehr hoch.
Kluge Felix, Pasluosta Cristian, Gassner Heiko, Klucken Jochen, Eskofier Bjoern M
Motionlab@ Home: Complementary Measurement of Gait Characteristics Using Wearable Technology and Markerless Video Tracking-A Study Protocol.
2016 Advanced Engineering Forum, Band: 19
Stutzki H, Helmhold F, Eickenscheidt M, Zeck G
Subretinal electrical stimulation reveals intact network activity in the blind mouse retina.
2016 J Neurophysiol, Seiten: jn.01095.2015 - jn.01095.2015
Stieglitz T, Paul O, Wallrabe U, Ruther P
Track U. BrainLinks-BrainTools-Methods and tools for neural engineering.
2016 Biomed Tech, Band: 61, Nummer: s1, Seiten: 234 - 243

2015

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Boehler C, Asplund M
A detailed insight into drug delivery from PEDOT based on analytical methods: Effects and side effects.
2015 J Biomed Mater Res A, Band: 103, Nummer: 3, Seiten: 1200 - 1207
KurzfassungThe possibility to release drugs from conducting polymers, like polypyrrole or poly(3,4‐ethylenedioxythiophene) (PEDOT), has been described and investigated for a variety of different substances during the last years, showing a wide interest in these release systems. A point that has not been looked at so far however is the possibility of other substances, next to the intended ones, leaving the polymer film under the high voltage excursions during redox sweeping. In this study we target this weakness of commonly used detection methods by implementing a high precision analytical method (high‐performance liquid chromatography) that allows a separation and subsequently a detailed quantification of all possible release products. We could identify a significantly more complex release behavior for a PEDOT:Dex system than has been assumed so far, revealing the active release of the monomer upon redox activation. The released EDOT could thereby be shown to result from the bulk material, causing a considerable loss of polymer (>10% during six release events) that could partly account for the observed degradation or delamination effects of drug‐eluting coatings. The monomer leakage was found to be substantially higher for a PEDOT:Dex film compared to a PEDOT:PSS sample. This finding indicates an overestimation of drug release if side products are mistaken for the actual drug mass. Moreover the full picture of released substances implements the need for further studies to reduce the monomer leakage and identify possible adverse effects, especially in the perspective of releasing an anti‐inflammatory substance for attenuation of the foreign body reaction toward implanted electrodes.
Kreshuk A, Walecki R, Koethe U, Gierthmuehlen M, Plachta D, Genoud C, Haastert-Talini K, Hamprecht FA
Automated tracing of myelinated axons and detection of the nodes of Ranvier in serial images of peripheral nerves.
2015 J Microsc-oxford, Band: 259, Nummer: 2, Seiten: 143 - 154
KurzfassungThe development of realistic neuroanatomical models of peripheral nerves for simulation purposes requires the reconstruction of the morphology of the myelinated fibres in the nerve, including their nodes of Ranvier. Currently, this information has to be extracted by semimanual procedures, which severely limit the scalability of the experiments. In this contribution, we propose a supervised machine learning approach for the detailed reconstruction of the geometry of fibres inside a peripheral nerve based on its high-resolution serial section images. Learning from sparse expert annotations, the algorithm traces myelinated axons, even across the nodes of Ranvier. The latter are detected automatically. The approach is based on classifying the myelinated membranes in a supervised fashion, closing the membrane gaps by solving an assignment problem, and classifying the closed gaps for the nodes of Ranvier detection. The algorithm has been validated on two very different datasets: (i) rat vagus nerve subvolume, SBFSEM microscope, 200 × 200 × 200 nm resolution, (ii) rat sensory branch subvolume, confocal microscope, 384 × 384 × 800 nm resolution. For the first dataset, the algorithm correctly reconstructed 88% of the axons (241 out of 273) and achieved 92% accuracy on the task of Ranvier node detection. For the second dataset, the gap closing algorithm correctly closed 96.2% of the gaps, and 55% of axons were reconstructed correctly through the whole volume. On both datasets, training the algorithm on a small data subset and applying it to the full dataset takes a fraction of the time required by the currently used semiautomated protocols. Our software, raw data and ground truth annotations are available at http://hci.iwr.uni-heidelberg.de/Benchmarks/. The development version of the code can be found at https://github.com/RWalecki/ATMA. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.
Maciejasz P, Badia J, Boretius T, Andreu D, Stieglitz T, Jensen W, Navarro X, Guiraud D
Delaying discharge after the stimulus significantly decreases muscle activation thresholds with small impact on the selectivity: an in vivo study using TIME.
2015 Med Biol Eng Comput, Band: 53, Nummer: 4, Seiten: 371 - 379
Koch J, Ordonez JS, Stieglitz T, Schuettler M
Development of a multichannel implantable connector.
2015 Conf Proc IEEE Eng Med Biol Soc, Band: 2015, Seiten: 805 - 808
Gierthmuehlen M, Plachta DT
Effect of selective vagal nerve stimulation on blood pressure, heart rate and respiratory rate in rats under metoprolol medication.
2015 Hypertens Res
Qiao S, Stieglitz T, Yoshida K
Estimation of the Electrode-fiber Bioelectrical Coupling from Extracellularly Recorded Single Fiber Action Potentials.
2015 Ieee T Neur Sys Reh
Erhardt JB, Leupold J, Fuhrer E, Gruschke OG, Wapler MC, Hennig J, Korvink JG, Stieglitz T
Influence of Pt/Ir electrode thickness on magnetic resonance imaging susceptibility artefacts.
2015 Biomed Eng-biomed Te, Band: 60 Suppl 1, Seiten: s193 - s226
Stitt I, Galindo-Leon E, Pieper F, Engler G, Fiedler E, Stieglitz T, Engel AK
Intrinsic coupling modes reveal the functional architecture of cortico-tectal networks.
2015 science advances, Band: 1, Nummer: 7, Seiten: e1500229 - e1500229
Boehler C, Stieglitz T, Asplund M
Nanostructured platinum grass enables superior impedance reduction for neural microelectrodes.
2015 Biomaterials, Band: 67, Seiten: 346 - 353
Boeser F, Ordonez JS, Schuettler M, Stieglitz T, Plachta DT
Non-hermetic encapsulation for implantable electronic devices based on epoxy.
2015 Conf Proc IEEE Eng Med Biol Soc, Band: 2015, Seiten: 809 - 812
Volk T, Gorbey S, Bhattacharyya M, Gruenwald W, Lemmer B, Reindl LM, Stieglitz T, Jansen D
RFID Technology for Continuous Monitoring of Physiological Signals in Small Animals.
2015 Ieee T Bio-med Eng, Band: 62, Nummer: 2, Seiten: 618 - 626
Barth J, Oberndorfer C, Pasluosta C, Schulein S, Gassner H, Reinfelder S, Kugler P, Schuldhaus D, Winkler J, Klucken J, Eskofier BM
Stride segmentation during free walk movements using multi-dimensional subsequence dynamic time warping on inertial sensor data.
2015 Sensors-basel, Band: 15, Nummer: 3, Seiten: 6419 - 6440
Harreby KR, Kundu A, Yoshida K, Boretius T, Stieglitz T, Jensen W
Subchronic stimulation performance of transverse intrafascicular multichannel electrodes in the median nerve of the Gottingen minipig.
2015 Artif Organs, Band: 39, Nummer: 2, Seiten: E36 - E48
Stieglitz T
Technically assisted rehabilitation - approaches for the upper extremity.
2015 Biomed Tech, Band: 60, Nummer: 3, Seiten: 177 - 178

2014

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Rieger R, Schuettler M, Chuang SC
A device for emulating cuff recordings of action potentials propagating along peripheral nerves.
2014 Ieee T Neur Sys Reh, Band: 22, Nummer: 5, Seiten: 937 - 945
Kohler F, Kiele P, Ordonez JS, Stieglitz T, Schuettler M
A polymer-metal two step sealing concept for hermetic neural implant packages.
2014 Conf Proc IEEE Eng Med Biol Soc, Band: 2014, Seiten: 3981 - 3984
Eickenscheidt M, Zeck G
Action potentials in retinal ganglion cells are initiated at the site of maximal curvature of the extracellular potential.
2014 J Neural Eng, Band: 11, Nummer: 3, Seiten: 036006 - 036010
Asplund M, Boehler C, Stieglitz T
Anti-inflammatory polymer electrodes for glial scar treatment: bringing the conceptual idea to future results.
2014 Front Neuroeng, Band: 7, Seiten: 9 - 9
KurzfassungConducting polymer films offer a convenient route for the functionalization of implantable microelectrodes without compromising their performance as excellent recording units. A micron thick coating, deposited on the surface of a regular metallic electrode, can elute anti-inflammatory drugs for the treatment of glial scarring as well as growth factors for the support of surrounding neurons. Electro-activation of the polymer drives the release of the substance and should ideally provide a reliable method for controlling quantity and timing of release. Driving signals in the form of a constant potential (CP), a slow redox sweep or a fast pulse are all represented in literature. Few studies present such release in vivo from actual recording and stimulating microelectronic devices. It is essential to bridge the gap between studies based on release in vitro, and the intended application, which would mean release into living and highly delicate tissue. In the biological setting, signals are limited both by available electronics and by the biological safety. Driving signals must not be harmful to tissue and also not activate the tissue in an uncontrolled manner. This review aims at shedding more light on how to select appropriate driving parameters for the polymer electrodes for the in vivo setting. It brings together information regarding activation thresholds for neurons, as well as injury thresholds, and puts this into context with what is known about efficient driving of release from conducting polymer films.
Yoshida K, Stieglitz T, Shaoyu Qiao
Bioelectric interfaces for the peripheral nervous system.
2014 Conf Proc IEEE Eng Med Biol Soc, Band: 2014, Seiten: 5272 - 5275
Plachta DT *, Gierthmuehlen M *, Cota O, Espinosa N, Boeser F, Herrera TC, Stieglitz T, Zentner J
Blood pressure control with selective vagal nerve stimulation and minimal side effects.
2014 J Neural Eng, Band: 11, Nummer: 3, Seiten: 036011 - 036011
Plachta DT, Gierthmuehlen M, Cota O, Espinosa N, Boeser F, Herrera TC, Stieglitz T, Zentner J
Blood pressure control with selective vagal nerve stimulation and minimal side effects.
2014 J Neural Eng, Band: 11, Nummer: 3, Seiten: 036011 - 036011
Ordonez JS, Pikov V, Wiggins H, Patten C, Stieglitz T, Rickert J, Schuettler M
Cuff electrodes for very small diameter nerves - Prototyping and first recordings in vivo.
2014 Conf Proc IEEE Eng Med Biol Soc, Band: 2014, Seiten: 6846 - 6849
Somerlik K H, Stieglitz T, Schulze-Bonhage A
Evaluation von Parametern zur Hirnstimulation
2014 Zeitschrift für Epileptologie, Band: 27, Seiten: 7 - 18
Kim YJ, Jin YH, Salieb-Beugelaar GB, Nam CH, Stieglitz T
Genetically engineered bacteriophage delivers a tumor necrosis factor alpha antagonist coating on neural electrodes.
2014 Biomed Mater, Band: 9, Nummer: 1, Seiten: 015009 - 015009
Theodor M, Ruh D, Subramanian S, Forster K, Heilmann C, Beyersdorf F, Plachta D, Manoli Y, Zappe H, Seifert A
Implantable pulse oximetry on subcutaneous tissue.
2014 Conf Proc IEEE Eng Med Biol Soc, Band: 2014, Seiten: 2089 - 2092
KurzfassungBlood oxygen saturation is one of the most prominent measurement parameters in daily clinical routine. However up to now, it is not possible to continuously monitor this parameter reliably in mobile patients. High-risk patients suffering from cardiovascular diseases could benefit from long-term monitoring of blood oxygen saturation. In this paper, we present a minimally invasive, implantable patient monitor which is capable of monitoring vital signs. The capability of this multimodal sensor to subcutaneously determine blood pressure, pulse and ECG has been demonstrated earlier. This paper focuses on monitoring of blood oxygen saturation. Even though the signal amplitudes are much weaker than for standard extracorporeal measurements, photoplethysmographic signals were recorded with high quality in vivo directly on subcutaneous muscle tissue. For the first time, it has been shown that blood oxygen saturation can be measured with an implantable, but extravascular sensor. The sensor was implanted for two weeks in a sheep and did not cause any complications. This opens new perspectives for home monitoring of patients with cardiovascular diseases.
Xie Y, Martini N, Hassler C, Kirch RD, Stieglitz T, Seifert A, Hofmann UG
In vivo monitoring of glial scar proliferation on chronically implanted neural electrodes by fiber optical coherence tomography.
2014 Front Neuroeng, Band: 7, Seiten: 34 - 34
Gierthmuehlen M, Wang X, Gkogkidis A, Henle C, Fischer J, Fehrenbacher T, Kohler F, Raab M, Mader I, Kuehn C, Foerster K, Haberstroh J, Freiman TM, Stieglitz T, Rickert J, Schuettler M, Ball T
Mapping of sheep sensory cortex with a novel microelectrocorticography grid.
2014 J Comp Neurol, Band: 522, Nummer: 16, Seiten: 3590 - 3608
Kohler F, Stieglitz T, Schuettler M
Morphological and electrochemical properties of an explanted PtIr electrode array after 15 months in vivo.
2014 Conf Proc IEEE Eng Med Biol Soc, Band: 2014, Seiten: 418 - 421
Stieglitz T, Neves H, Ruther P
Neural probes-microsystems to interface with the brain.
2014 Biomed Tech, Band: 59, Nummer: 4, Seiten: 269 - 271
Nataraj R, Pasluosta C, Li ZM
Online kinematic regulation by visual feedback for grasp versus transport during reach-to-pinch.
2014 Hum Movement Sci, Band: 36, Seiten: 134 - 153
Volk T, Gorbey S, Grunwald W, Bhattacharyya M, Lemmer B, Reindl L, Stieglitz T, Jansen D
RFID Technology for Continuous Monitoring of Physiological Signals in Small Animals.
2014 Ieee T Bio-med Eng, Band: 62, Nummer: 2, Seiten: 618 - 626
Zeck G, Helmhold F, Eickenscheidt M
Receptive field properties in healthy and blind mouse retinas evaluated by stimulation using an implantable subretinal microchip
2014 Invest Ophth Vis Sci, Band: 55, Nummer: 13, Seiten: 5966 - 5966
Raspopovic S, Capogrosso M, Petrini FM, Bonizzato M, Rigosa J, Di Pino G, Carpaneto J, Controzzi M, Boretius T, Fernandez E, Granata G, Oddo CM, Citi L, Ciancio AL, Cipriani C, Carrozza MC, Jensen W, Guglielmelli E, Stieglitz T, Rossini PM, Micera S
Restoring natural sensory feedback in real-time bidirectional hand prostheses.
2014 Sci Transl Med, Band: 6, Nummer: 222, Seiten: 222ra19 - 222ra19
Kundu A, Harreby KR, Yoshida K, Boretius T, Stieglitz T, Jensen W
Stimulation selectivity of the "thin-film longitudinal intrafascicular electrode" (tfLIFE) and the "transverse intrafascicular multi-channel electrode" (TIME) in the large nerve animal model.
2014 Ieee T Neur Sys Reh, Band: 22, Nummer: 2, Seiten: 400 - 410
Fiedler E, Haas N, Stieglitz T
Suitability of SU-8, EpoClad and EpoCore for flexible waveguides on implantable neural probes.
2014 Conf Proc IEEE Eng Med Biol Soc, Band: 2014, Seiten: 438 - 441

2013

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Rubehn B, Wolff S, Tovote P, Luethi A, Stieglitz T
A Polymer-based Neural Microimplant for Optogenetic Applications: Design and First In Vivo Study.
2013 Lab Chip, Band: 13, Nummer: 4, Seiten: 579 - 588
KurzfassungIn optogenetics, neurons are genetically modified to become sensitive to light and thus, they can be stimulated or inhibited by light of certain wavelengths. In this work, we describe the fabrication of a polymer-based shaft electrode as a tool for optogenetics. This device can conduct light as well as fluids to a target brain region and record electrical neural signals from the same part of the tissue simultaneously. It is intended to facilitate optogenetic in vivo experiments with those novel multimodal neural probes or polymer optrodes. We used microsystems technology to integrate an SU-8 based waveguide and fluidic channel into a polyimide-based electrode shaft to allow simultaneous optical stimulation, fluid delivery, and electrophysiological recording in awake behaving animals. In a first acute proof-of-concept experiment in genetically modified mice, our device recorded single unit activity that was modulated by laser light transmitted into the tissue via the integrated waveguide.

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Plachta DT, Gierthmuehlen M, Cota O, Boeser F, Stieglitz T
BaroLoop: using a multichannel cuff electrode and selective stimulation to reduce blood pressure.
2013 Conf Proc IEEE Eng Med Biol Soc, Band: 2013, Seiten: 755 - 758
Kundu A, Harreby K, Yoshida K, Boretius T, Stieglitz T, Jensen W
Comparison of muscle recruitment selectivity during stimulation of the longitudinal or the transverse intrafascicular electrodes (tfLIFE and TIME)in the large nerve animal model
2013 Ieee T Neur Sys Reh
Gierthmuehlen M*, Plachta DTT*, Unni A, Haastert-Talini K, Stieglitz T, Kaminsky J, Freiman T
Computational tissue volume reconstruction of a peripheral nerve derived from composing series of high-resolution light-microscopic images with the Open-Source software Reconstruct
2013 Plos One, Band: 8, Nummer: 6
KurzfassungThe development of neural cuff-electrodes requires several in vivo studies and revisions of the electrode design before the electrode is completely adapted to its target nerve. It is therefore favorable to simulate many of the steps involved in this process to reduce costs and animal testing. As the restoration of motor function is one of the most interesting applications of cuff-electrodes, the position and trajectories of myelinated fibers in the simulated nerve are important. In this paper, we investigate a method for building a precise neuroanatomical model of myelinated fibers in a peripheral nerve based on images obtained using high-resolution light microscopy. This anatomical model describes the first aim of our "Virtual workbench" project to establish a method for creating realistic neural simulation models based on image datasets. The imaging, processing, segmentation and technical limitations are described, and the steps involved in the transition into a simulation model are presented. The results showed that the position and trajectories of the myelinated axons were traced and virtualized using our technique, and small nerves could be reliably modeled based on of light microscopy images using low-cost OpenSource software and standard hardware. The anatomical model will be released to the scientific community. Computational Tissue Volume Reconstruction of a Peripheral Nerve Using High-Resolution Light-Microscopy and Reconstruct. Available from: https://www.researchgate.net/publication/240307104_Computational_Tissue_Volume_Reconstruction_of_a_Peripheral_Nerve_Using_High-Resolution_Light-Microscopy_and_Reconstruct [accessed Apr 20, 2017].
Gierthmuehlen M *, Freiman TM, Haastert-Talini K, Mueller A, Kaminsky J, Stieglitz T *, Plachta DT
Computational tissue volume reconstruction of a peripheral nerve using
2013 Plos One, Band: 8, Nummer: 6, Seiten: e66191 - e66191
Prystaz K, Ulmer C, Somerlik-Fuchs KH, Krueger TB
Establishment of an in Vitro Model for Stress Testing of Vagal Nerve Cuff Electrodes.
2013 Biomed Tech
von Metzen R, Stieglitz T
Impact of Sterilization Procedures on the Stability of Parylene Based Flexible Multilayer Structures
2013 Biomed Tech
von Metzen R, Stieglitz T
Impact of Sterilization Procedures on the Stability of Parylene Based Flexible Multilayer Structures.
2013 Biomed Tech
Pasluosta CF, Domalain MM, Fang Y, Yue GH, Li ZM
Influence of nerve supply on hand electromyography coherence during a three-digit task.
2013 J Electromyogr Kines, Band: 23, Nummer: 3, Seiten: 594 - 599
Fiedler E, Ordonez JS, Stieglitz T
Laser-structured ceramic adapters for reliable assembly of flexible thin-film electrodes.
2013 Biomed Tech
Plachta D *, Cota O, Stieglitz T, Gierthmuehlen M *
Selektive Ableitung und Stimulation für ein blutdrucksenkendes Implantat unter Verwendung von Vielkanal-Cuff-Elektroden
2013 Tm-tech Mess, Band: 80, Nummer: 5, Seiten: 163 - 172
KurzfassungThe localization of baroreceptive fibers in the vagal nerve and their selective stimulation are key requirements to establish vagus nerve stimulation as an alternative therapy for patients suffering from therapy refractory hypertension. The selectivity of this stimulation is therefore essential as a non-selective stimulation of the entire vagus causes cardial and gastrointestinal side effects, which are unacceptable for chronic therapy. Through the use of multichannel-polyimide thinfilm cuff electrodes, it is possible to locate and selectively stimulate these baroreceptive fibers. The signals recorded are in realtime correlated to ECG and blood pressure signals to identify those electrodes which are closest to the baroreceptive fibers. The algorithm developed for this purpose is based on the coherent averaging and requires no constant electrode-tissue impedance. Electrodes found proximal to the baroreceptive fibers are used as tri- or pentapolar stimulation electrodes. Selective stimulation over these electrodes results in activation of the baroreflex decreasing the blood pressure while simultaneousely avoiding any significant bradycardia.
von Metzen R, Stieglitz T
The Effects of Annealing on Mechanical, Chemical, and Physical Properties and Structural Stability of Parylene C
2013 Biomed Microdevices, Band: 15, Nummer: 5, Seiten: 727 - 735

Datei herunterladen
Kohler F, Johannsen B, Haas N, Ordonez JS, Stieglitz T, Schuettler M
The Influence of Flux on the Reliability of Solder-Sealed Hermetic Packages for Active Implantable Medical Devices.
2013 Biomed Tech
von Metzen RP, Stieglitz T
The effects of annealing on mechanical, chemical, and physical properties and structural stability of Parylene C.
2013 Biomed Microdevices, Band: 15, Nummer: 5, Seiten: 727 - 735
Schuettler M, Huegle S, Ordonez JS, Stieglitz T
Towards the Development of Implantable Connectors with High Contact Number.
2013 Biomed Tech

2012

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Ordonez J, Schuettler M, Ortmanns M, Stieglitz T
A 232-Channel Retinal Vision Prosthesis with a Miniaturized Hermetic Package
2012 34th Annual International Conference of the IEEE EMBS, San Diego, California, USA, 28 August - 1 September, 2012, Seiten: 2796 - 2799
Plachta DT, Espinosa N, Gierthmuehlen M, Cota O, Herrera TC, Stieglitz T
Detection of baroreceptor activity in rat vagal nerve recording using a multi-channel cuff-electrode and real-time coherent averaging.
2012 Conf Proc IEEE Eng Med Biol Soc, Band: 2012, Seiten: 3416 - 3419
KurzfassungElectrical stimulation of afferent nerve fibers originating from pressure sensors can trigger the baroreflex to reduce blood pressure and might be an alternative to treat patients with hypertension. In this study, baroreceptor compound activity was detected using multi-channel cuff-electrode recordings on rat vagal nerve. In order to isolate the vagal nerve signals from external potentials (such as ECG- and EMG-coupling), a tripolar measuring technique was applied. To eliminate noise and neural signals corresponding to other organs, coherent averaging was used. The baroreceptor-correlated signals appear predominantly in one of the electrode channels, presumably close to the corresponding neural substrate. This localization was done in real-time.
Stieglitz T, Boretius T, Navarro V, Badia J, Guiraud D, Divoux J, Micera S, Rossini P, Yoshida K, Harreby K, Kundu A, Jensen W
Development of a Neurotechnological System for Relieving Phantom Limb Pain Using Transverse Intrafascicular Electrodes
2012 Biomed Tech, Band: 57, Nummer: 6, Seiten: 457 - 465
KurzfassungPhantom limb pain (PLP) is a chronic condition that develops in the majority of amputees. The underlying mechanisms are not completely understood, and thus, no treatment is fully effective. Based on recent studies, we hypothesize that electrical stimulation of afferent nerves might alleviate PLP by giving sensory input to the patient if nerve fibers can be activated selectively. The critical component in this scheme is the implantable electrode structure. We present a review of a novel electrode concept to distribute highly selective electrode contacts over the complete cross section of a peripheral nerve to create a distributed activation of small nerve fiber ensembles at the fascicular level, the transverse intrafascicular multichannel nerve electrode (TIME). The acute and chronic implantations in a small animal model exhibited a good surface and structural biocompatibility as well as excellent selectivity. Implantation studies on large animal models that are closer to human nerve size and anatomical complexity have also been conducted. They proved implant stability and the ability to selectively activate nerve fascicles in a limited proximity to the implant. These encouraging results have opened the way forward for human clinical trials in amputees to investigate the effect of selective electrical stimulation on PLP.

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Eickenscheidt M, Jenkner M, Thewes R, Fromherz P, Zeck G
Electrical stimulation of retinal neurons in epiretinal and subretinal configuration using a multicapacitor array.
2012 J Neurophysiol, Band: 107, Nummer: 10, Seiten: 2742 - 2755
Pasluosta CF, Chiu AW
Evaluation of a neural network-based control strategy for a cost-effective externally-powered prosthesis.
2012 Assist Technol, Band: 24, Nummer: 3, Seiten: 196 - 208
Somerlik-Fuchs KH, Krueger T, Carpaneto J, Stieglitz T, Micera S
Hand Prostheses Control by Using Natural Electromyographic Pattern Obtained in Grasping Tasks
2012 J Bioelectromagnetism, Band: 14, Nummer: 4, Seiten: 185 - 189

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Schuettler M, Kohler F, Ordonez JS, Stieglitz T
Hermetic electronic packaging of an implantable brain-machine-interface with transcutaneous optical data communication.
2012 Conf Proc IEEE Eng Med Biol Soc, Band: 2012, Seiten: 3886 - 3889
Schuettler M, Stieglitz T
Intelligent Telemetric Implants
2012 Biomed Tech (Berl), Band: 57, Ergänzungsband: 1, Seiten: 967 - 970
Hartbauer M, Krueger TB, Stieglitz T
Possibilities offered by implantable miniaturized cuff-electrodes for insect neurophysiology
2012 Neurocomputing, Band: 84, Nummer: 1, Seiten: 3 - 12
Plachta DTT, Gierthmühlen M, Stieglitz T
Selective Stimulation of the Vagal Nerve Reduces Blood Pressure without Side Effects
2012 Biomed Tech 2012, Nummer: 57, Ergänzungsband: 1, Seiten: 594 - 594
KurzfassungIncreased blood pressure (hypertension)affects 25 % of the German population. Even though most patients benefit from pharmaceutical treatments, blood pressure cannot be reliably lowered to physiological values in all of them. Some patients are medically refractory and do not benefit from drug therapy at all. Modulation of signals from afferent fibresfrom pressure sensors of the aortic arch and the carotid artery by electrical stimulation can trigger the so - called baroreflex and lower the blood pressure.The stimulation of those pressure receptors is highly effective and free from side effects. However, surgical intervention and interfacing of the carotid artery are associated with high risk . Malfunction of an implant may lead to life threatening situations. Vagal nerve stimulation (VNS) is established in clinical practice. Nerve surrounding electrodes are considered a safe implantation technology. Since the vagal nerve is one major communication path way in the vegetative nervous system, global stimulation causes secondary effects such as nausea, vomiting,and even arrhythmia, for example. Afferent nerve fibres of the blood pressure sensors are also located in the vagal nerve. Selective stimulation of these fibres should lower the blood pressure without causing major side effects.
Bosman C, Schoeffelen JM, Oostenfeld R, Womelsdorf T, Brunet N, Rubehn B, Stieglitz T, de Weers P, Fries P
Stimulus Selection through Selective Synchronization between Money Visual Areas
2012 Mrs Bull, Band: 75, Nummer: 5, Seiten: 875 - 888
Stieglitz T, Niemann H, Kraft M
Technically Assisted Rehabilitation
2012 Biomed Tech, Band: 57, Nummer: 6, Seiten: 423 - 425

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Taylor J, Schuettler M, Clarke C, Donaldson N
The Theory of Velocity Selective Neural Recording: a Study Based on Simulation
2012 Med Biol Eng Comput, Band: 50, Nummer: 3, Seiten: 309 - 318
Ordonez J, Schuettler M, Boehler C, Boretius T, Stieglitz T
Thin Films and Microelectrode Arrays for Neuroprosthetics
2012 MRS Bulletin, Band: 37, Nummer: 6, Seiten: 590 - 598

2011

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Schuettler M, Ordonez JS, Schatz A, Stieglitz T
A Hermetic Implant Housing with Large Number of Electrical Feedthroughs, Transparent to Infrared Light and Magnetic Fields
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Jin Y-H, Daubinger P, Fiebich B, Stieglitz T
A Neural Electrode Coated by Platinum Nanowires
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Ordonez J, Boehler C, Schuettler M, Stieglitz T
A blister-test apparatus for studies on the adhesion of materials used for neural electrodes.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 2953 - 2956
Henle C, Fischer J, Meier W, Rickert J, Schuettler M, Stieglitz T
A flexible ECoG-Electrode with high resolution for BRAINCON - a wireless implantable system for long-term recording and stimulation
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Zariffa J, Nagai MK, Schuettler M, Stieglitz T, Daskalakis ZJ, Popovic MR
A framework for the discrimination of neural pathways using multi-contact nerve cuff electrodes.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 4645 - 4648
Rubehn B, Wolff S, Tovote P, Lüthi A, Stieglitz T
A micromachined tool for optogenetic investigations in the brain
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Pfau D, Krüger TB, Somerlik KH, Mattmüller R, Stieglitz T
A novel technique for monitoring the facial nerve during drilling in otologic surgery
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Badia J, Boretius T, Udina E, Stieglitz T, Navarro X
Biocompatibility of chronically implanted transverse intrafascicular multichannel electrode (TIME) in the rat sciatic nerve
2011 Ieee T Bio-med Eng, Band: 58, Nummer: 8, Seiten: 2324 - 2332
Wang X, Gierthmuehlen M, Henle C, Raab M, Aertsen A, Schulze-Bonhage
Brain mapping using μECoG signals in the 250-400 Hz band
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Eickenscheidt M, Fromherz P, Zeck G
Capacitive Stimulation of Retinal Neurons in Epiretinal and Subretinal Configuration
2011 Invest Ophth Vis Sci, Band: 52, Nummer: 14, Seiten: 2591 - 2591
Hassler C, Guy J, Nietzschmann M, Staiger JF, Stieglitz T
Chronic Intracortical Implantation of Saccharose-Coated Flexible Shaft Electrodes into the Cortex of Rats.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 644 - 647
Badia J, Boretius T, Andreu D, Azevedo-Coste C, Stieglitz T, Navarro X
Comparative analysis of transverse intrafascicular multichannel, longitudinal intrafascicular and multipolar cuff electrodes for the selective stimulation of nerve fascicles.
2011 J Neural Eng, Band: 8, Nummer: 3, Seiten: 036023 - 036023
Rubehn BS, chneider I, Rutishauser U, Laurent G, Stieglitz T
Comparing electrode sizes in epicortical local field potential recording
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Townsend BR, Engler G, Pieper F, Galindo-Leon EE, Engel AK, Stieglitz T
Development of a novel thin-film ECoG array for cortical recording and stimulation
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
von Metzen RP, Lass N, Ruther P, Stieglitz T
Diffusion-Limited Deposition of Parylene C
2011 J Microelectromech S , Band: 20, Nummer: 1, Seiten: 239 - 250
Schuettler M, Schatz A, Ordonez JS, Stieglitz T
Ensuring minimal humidity levels in hermetic implant housings.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 2296 - 2299
Gierthmuehlen M, Ball T, Henle C, Wang X, Rickert J, Raab M, Freiman T, Stieglitz T, Kaminsky J
Evaluation of muECoG electrode arrays in the minipig: experimental procedure and neurosurgical approach.
2011 J Neurosci Meth, Band: 202, Nummer: 1, Seiten: 77 - 86
Henle C, Raab M, Cordeiro JG, Doostkam S, Schulze-Bonhage A, Stieglitz T, Rickert J
First long term in vivo study on subdurally implanted micro-ECoG electrodes, manufactured with a novel laser technology.
2011 Biomed Microdevices, Band: 13, Nummer: 1, Seiten: 59 - 68
Boretius T, Jurzinsky T, Koehler C, Kerzenmacher S, Hillebrecht H, Stieglitz T
High-porous platinum electrodes for functional electrical stimulation.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 5404 - 5407
Lambacher A, Vitzthum V, Zeitler R, Eickenscheidt M, Eversmann B, Thewes R, Fromherz P
Identifying firing mammalian neurons in networks with high-resolution multi-transistor array (MTA)
2011 Appl Phys A-mater, Band: 102, Nummer: 1, Seiten: 1 - 11
Plachta DTT, Cota O, Stieglitz T
Implantable polyimide mapping cuff electrode
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Hassler C, Guy J, Nietzschmann M, Staiger JF, Stieglitz T
Implantation of stiffened polymer-based shaft electrodes into the cortex of rats
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Cota O, Kuhl M, Stieglitz T, Manoli Y, Plachta DTT
Low Noise CMOS-Integrated Amplifier for Electroneurogram(ENG) Recordings
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Henle C, Hassler C, Kohler F, Schuettler M, Stieglitz T
Mechanical characterization of neural electrodes based on PDMS-parylene C-PDMS sandwiched system.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 640 - 643
Kohler F, Schuettler M, Stieglitz T
Microfabrication of parylene coated tracks for neural electrode arrays - preliminary results using a Nd:YAG laser
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Boretius T, Schuettler M, Stieglitz T
On the stability of poly-ethylenedioxythiopene as coating material for active neural implants.
2011 Artif Organs, Band: 35, Nummer: 3, Seiten: 245 - 248
Rubehn B, Wolff S, Tovote P, Schuettler M, Luthi A, Stieglitz T
Polymer-based shaft microelectrodes with optical and fluidic capabilities as a tool for optogenetics.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 2969 - 2972
Hassler C, Boretius T, Stieglitz T
Polymers for Neural Implants
2011 J Polym Sci Pol Phys , Band: 49, Nummer: 1, Seiten: 18 - 33
Somerlik KH, Cosandier-Rimélé D, Cordeiro JG, Krüger TB, Mattmüller R, Stieglitz T, Aertsen A, Schulze-Bonhage A
Quantifying Tendency to Epileptic Activity in Rat Kainate Model
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Boretius T, Jurzinsky T, Köhler Ch, Kerzenmacher S, Stieglitz T
Raney-platinum electrodes for functional electrical stimulation
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
von Metzen RP, Hassler C, Stieglitz T
Setup for measuring the electrical properties of insulation layers in neural probes
2011 Biomed Tech, Band: 56, Ergänzungsband: 1
Stieglitz T, Kraft M
Technically assisted rehabilitation.
2011 Biomed Tech, Band: 56, Nummer: 1, Seiten: 3 - 4
Zariffa J, Nagai MK, Schuettler M, Stieglitz T, Daskalakis ZJ, Popovic MR
Use of an experimentally derived leadfield in the peripheral nerve pathway discrimination problem.
2011 Ieee T Neur Sys Reh, Band: 19, Nummer: 2, Seiten: 147 - 156

2010

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Boretius T, Badia J, Pascual-Font A, Schuettler M, Navarro X, Yoshida K, Stieglitz T
A transverse intrafascicular multichannel electrode (TIME) to interface with the peripheral nerve.
2010 Biosens Bioelectron, Band: 26, Nummer: 1, Seiten: 62 - 69
Sooksood K, Stieglitz T, Ortmanns M
An Active Approach for Charge Balancing in Functional Electrical Stimulation
2010 IEEE T Biomed Circ Syst, Band: 4, Nummer: 3, Seiten: 163 - 170
Schlötelburg C, Becks T, Stieglitz T
Biomedizinische Technik heute, eine Übersicht aus dem Blickwinkel der Deutschen Gesellschaft für Biomedizinische Technik
2010 Bundesgesundheitsbla, Band: 53, Nummer: 8, Seiten: 759 - 767
Hassler C, von Metzen RP, Ruther P, Stieglitz T
Characterization of Parylene C as an Encapsulation Material for Implanted Neural Prostheses.
2010 J Biomed Mater Res B, Band: 93, Nummer: 1, Seiten: 266 - 274
Green RA, Ordonez JS, Schuettler M, Poole-Warren LA, Lovell NH, Suaning GJ
Cytotoxicity of Implantable Microelectrode Arrays Produced by Laser Micromachining
2010 Biomaterials, Band: 31, Nummer: 5, Seiten: 886 - 893
Henle C, Madjarov A, Schuettler M, Stieglitz T
Evaluation of Cytotoxicity on Laser-Fabricated Neural Implants: Influence of Different Manufacturing Processes and Materials
2010 Implantable electrode arrays based on silicone rubber (PDMS) and a laser manufacturing technology, were investigated Biomed Tech, Band: 55, Seiten: 1 - 4
Rubehn B, Stieglitz T
In Vitro Evaluation of the Long-Term Stability of Polyimide as a Material for Neural Implants.
2010 Biomaterials, Band: 31, Nummer: 13, Seiten: 3449 - 3458
Stieglitz T
Integration of Microfluidic Capabilities into Micromachined Neural Implants
2010 Int J Micro-Nano Scale Transport , Band: 1, Nummer: 2, Seiten: 139 - 158
Stieglitz T
Manufacturing, Assembling and Packaging of Miniaturized Neural Implants
2010 Microsyst Technol, Band: 16, Nummer: 5, Seiten: 723 - 734
Stieglitz T
Neuroprothetik und Neuromodulation - Forschungsansätze und klinische Praxis bei Therapie und Rehabilitation
2010 Bundesgesundheitsbla, Band: 53, Nummer: 8, Seiten: 783 - 790
Singheiser M, Plachta DT, Brill S, Bremen P, van der Willigen RF, Wagner H
Target-approaching behavior of barn owls (Tyto alba): influence of sound frequency.
2010 J Comp Physiol A, Band: 196, Nummer: 3, Seiten: 227 - 240

2009

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Rubehn B, Bosman C, Oostenveld R, Fries P, Stieglitz T
A MEMS-based flexible multichannel ECoG-electrode array.
2009 J Neural Eng, Band: 6, Nummer: 3, Seiten: 036003 - 036003
Stieglitz T, Rubehn B, Henle C, Kisban S, Herwik S, Ruther P, Schuettler M
Brain-computer interfaces: an overview of the hardware to record neural signals from the cortex.
2009 Prog Brain Res, Band: 175, Seiten: 297 - 315
Stieglitz T
Development of a Micromachined Epiretinal Vision Prosthesis
2009 J Neural Eng, Band: 6, Nummer: 6, Seiten: 1 - 11

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Stieglitz T, Klausmann D, Krueger TB
Development of a simple low noise amplifier for recording of sensory mass signals from peripheral nerves.
2009 Biomed Tech, Band: 54, Nummer: 1, Seiten: 1 - 7
Pasluosta C, Tims H, Chiu L
Slippage sensory feedback and nonlinear force control system for a low-cost prosthetic hand
2009 Am J Biomed Sci, Band: 1, Nummer: 4, Seiten: 295 - 302

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2008

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Schuettler M, Franke M, Krueger TB, Stieglitz T
A voltage-controlled current source with regulated electrode bias-voltage for safe neural stimulation.
2008 J Neurosci Meth, Band: 171, Nummer: 2, Seiten: 248 - 252
Kisban S, Janssen P, Herwik S, Stieglitz T, Paul O, Ruther P
Hybrid microprobes for chronic implantation in the cerebral cortex.
2008 Conf Proc IEEE Eng Med Biol Soc, Band: 2008, Seiten: 2016 - 2019
Hausmann L, Plachta DT, Singheiser M, Brill S, Wagner H
In-flight corrections in free-flying barn owls (Tyto alba) during sound localization tasks.
2008 J Exp Biol, Band: 211, Nummer: Pt 18, Seiten: 2976 - 2988
Schuettler M, Henle C, Ordonez JS, Meier W, Guenther T, Stieglitz T
Interconnection technologies for laser-patterned electrode arrays.
2008 Conf Proc IEEE Eng Med Biol Soc, Band: 2008, Seiten: 3212 - 3215
Feili D, Schuettler M, Stieglitz T
Matrix-addressable, active electrode arrays for neural stimulation using organic semiconductors-cytotoxicity and pilot experiments in vivo.
2008 J Neural Eng, Band: 5, Nummer: 1, Seiten: 68 - 74
Farina D, Yoshida K, Stieglitz T, Koch KP
Multichannel thin-film electrode for intramuscular electromyographic recordings.
2008 J Appl Physiol, Band: 104, Nummer: 3, Seiten: 821 - 827
Donaldson N, Rieger R, Schuettler M, Taylor J
Noise and Selectivity of Velocity-Selective Multi-Electrode Nerve Cuffs
2008 Med Biol Eng Comput, Band: 46, Nummer: 10, Seiten: 1005 - 1018
Henle C, Schuettler M, Ordonez JS, Stieglitz T
Scaling limitations of laser-fabricated nerve electrode arrays.
2008 Conf Proc IEEE Eng Med Biol Soc, Band: 2008, Seiten: 4208 - 4211

2007

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Krueger TB, Stieglitz T
A naive and fast human computer interface controllable for the inexperienced - a performance study.
2007 Conf Proc IEEE Eng Med Biol Soc, Band: 2007, Seiten: 2508 - 2511
von Metzen RP, Stieglitz T
A wireless system for monitoring polymer encapsulations.
2007 Conf Proc IEEE Eng Med Biol Soc, Band: 2007, Seiten: 6601 - 6604
Schanze T, Hesse L, Lau C, Greve N, Haberer W, Kammer S, Doerge T, Rentzos A, Stieglitz T
An Optically Powered Single-Channel Stimulation Implant as Test System for Chronic Biocompatibility and Biostability of Miniaturized Retinal Vision Prostheses.
2007 Ieee T Bio-med Eng, Band: 54, Nummer: 6 Pt 1, Seiten: 983 - 992
Hosseini NH, Hoffmann R, Kisban S, Stieglitz T, Paul O, Ruther P
Comparative study on the insertion behavior of cerebral microprobes.
2007 Conf Proc IEEE Eng Med Biol Soc, Band: 2007, Seiten: 4711 - 4714
Rubehn B, Stieglitz T
Measurement of defects in spin coated polyimide films.
2007 Conf Proc IEEE Eng Med Biol Soc, Band: 2007, Seiten: 183 - 185
Pasluosta CF, Fontana JM, Beltramone DA, Taborda RAM
Microcontrolled air-mattress for ulcer by pressure prevention
2007 Journal of Physics: Conference Series, Band: 90, Nummer: 1
Kisban S, Herwik S, Seidl K, Rubehn B, Jezzini A, Umilta MA, Fogassi L, Stieglitz T, Paul O, Ruther P
Microprobe array with low impedance electrodes and highly flexible polyimide cables for acute neural recording.
2007 Conf Proc IEEE Eng Med Biol Soc, Band: 2007, Seiten: 175 - 178
Stieglitz T
Neural prostheses in clinical practice: biomedical microsystems in neurological rehabilitation.
2007 Acta Neurochir Suppl, Band: 97, Nummer: Pt 1, Seiten: 411 - 418
Stieglitz T
Restoration of neurological functions by neuroprosthetic technologies: future prospects and trends towards micro-, nano-, and biohybrid systems.
2007 Acta Neurochir Suppl, Band: 97, Nummer: Pt 1, Seiten: 435 - 442

2006

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Guiraud D, Stieglitz T, Koch KP, Divoux JL, Rabischong P
An Implantable Neuroprostheses for Standing and Walking in Paraplegia: 5 Year Patient Follow Up
2006 J Neural Engineering, Band: 3, Seiten: 268 - 275
Ramachandran A, Schuettler M, Lago N, Doerge T, Koch KP, Navarro X, Hoffmann KP, Stieglitz T
Design, in vitro and in vivo assessment of a multi-channel sieve electrode with integrated multiplexer.
2006 J Neural Eng, Band: 3, Nummer: 2, Seiten: 114 - 124
Feili D, Doerge T, Kammer S, Schuettler M, Stieglitz T
Flexible Organic Field Effect Transistors for Biomedical Microimplants using Polyimide and Parylene as gate material and isolator layer
2006 J Micromech Microeng, Band: 16, Seiten: 1555 - 1561
Stieglitz T
Neuro-technical Interfaces to the Central Nervous System
2006 Poiesis and Practice, Band: 4, Nummer: 2, Seiten: 95 - 109
Guiraud D, Stieglitz T, Taroni G, Divoux JL
Original Electronic Design to Perform Epiysial and Neural Stimulation in Paraplegia
2006 J Neural Engineering, Band: 3, Seiten: 276 - 286
Mikut R, Krüger T, Reischl M, Burmeister O, Rupp R, Stieglitz T
Regelungs- und Steuerungskonzepte für Neuroprothesen am Beispiel der oberen Extremität
2006 at-Automatisierungstechnik, Band: 54, Seiten: 523 - 536

2005

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Navarro X, Krueger TB, Lago N, Micera S, Stieglitz T, Dario P
A critical review of interfaces with the peripheral nervous system for the control of neuroprostheses and hybrid bionic systems.
2005 J Peripher Nerv Syst, Band: 10, Nummer: 3, Seiten: 229 - 258
Walter P, Kisvarday ZF, Görtz M, Alteheld N, Rössler G, Stieglitz T, Eysel UT
Cortical Activation with a Completely Implanted Wireless Retinal Prosthesis
2005 Invest Ophth Vis Sci, Band: 46, Nummer: 5, Seiten: 1780 - 1785
Stieglitz T
Diameter-dependent excitation of peripheral nerve fibers by multipolar electrodes during electrical stimulation.
2005 Expert Rev Med Devic, Band: 2, Nummer: 2, Seiten: 149 - 152
Feili D, Schuettler M, Doerge T, Kammer S, Stieglitz T
Encapsulation of Organic Field Effect Transistors for Flexible Biomedical Microimplants
2005 Sensor Actuat A-phys, Band: 120, Nummer: 1, Seiten: 101 - 109
Stieglitz T, Koch KP, Schuettler M
Flexible, Polyimide-Based Modular Implantable Biomedical Microsystems for Neural Prostheses
2005 Ieee Eng Med Biol, Band: 24, Nummer: 5, Seiten: 58 - 65
Stieglitz T, Schuettler M, Koch KP
Implantable biomedical microsystems for neural prostheses.
2005 Ieee Eng Med Biol, Band: 24, Nummer: 5, Seiten: 58 - 65
Süsselbeck T, Thielecke H, Weinschenk I, Reininger-Mack A, Stieglitz T, Metz J, Borggrefe M, Robitzki A, Haase KK
In vivo intravascular electric impedance spectroscopy using a new catheter with integrated microelectrodes.
2005 Basic Res Cardiol, Band: 100, Nummer: 1, Seiten: 28 - 34
Lago N, Ceballos D, Rodriguez FJ, Stieglitz T, Navaroo X
Long Term Assessment of Axonal Regeneration through Polyimide Regenerative Electrodes to Interface the Peripheral Nerve
2005 Biomaterials, Band: 26, Seiten: 2021 - 2031
Stieglitz T, Monz D, Koch KP
Über die Zell-Material-Schnittstelle von Neuroprothesen
2005 Materialprufung, Band: 47, Seiten: 101 - 105

2004

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Stieglitz T
Considerations on Surface and Structural Biocompatibility as Prerequisite for Long-Term Stability of Neural Prostheses
2004 J Nanosci Nanotechno, Band: 4, Nummer: 5, Seiten: 496 - 503
Stieglitz T, Haberer W, Lau C, Goertz M
Development of an inductively coupled epiretinal vision prosthesis.
2004 Conf Proc IEEE Eng Med Biol Soc, Band: 6, Seiten: 4178 - 4181
Higgs DM, Plachta DT, Rollo AK, Singheiser M, Hastings MC, Popper AN
Development of ultrasound detection in American shad (Alosa sapidissima).
2004 J Exp Biol, Band: 207, Nummer: Pt 1, Seiten: 155 - 163
Schneider A, Stieglitz T
Implantable Flexible Electrodes for Functional Electrical Stimulation (FES)
2004 Medical Device Technology, Seiten: 16 - 18
Stieglitz T
Neural Prostheses and Functional Electrical Stimulation
2004 Biomed Tech, Band: 49, Nummer: 4, Seiten: 70 - 71
Stieglitz T, Schüttler M, Koch KP
Neural Prostheses in Clinical Applications - Trends from Precision Mechanics towards Biomedical Microsystems in Neurological Rehabilitation
2004 Biomed Tech, Band: 49, Nummer: 4, Seiten: 72 - 77
Plachta DT, Song J, Halvorsen MB, Popper AN
Neuronal encoding of ultrasonic sound by a fish.
2004 J Neurophysiol, Band: 91, Nummer: 6, Seiten: 2590 - 2597
Laube T, Brockmann C, Buss R, Lau C, Höck K, Stawski N, Stieglitz T, Richter HA, Schilling H
Optical Energy Transfer for Intraocular Microsystems Studied in Rabbits
2004 Graef Arch Clin Exp, Band: 242, Seiten: 661 - 667
Seif C, Herberger B, Cherwon E, Martinez Portillo FJ, Molitor M, Stieglitz T, Böhler G, Zendler S, Jünemann KP, Braun PM
Urinary Bladder Volume by Means of a Single Rectosymphysically Implantable Ultrasound Unit
2004 Neurourol Urodynam, Band: 23, Nummer: 7, Seiten: 680 - 684

2003

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Plachta DT, Hanke W, Bleckmann H
A hydrodynamic topographic map in the midbrain of goldfish Carassius auratus.
2003 J Exp Biol, Band: 206, Nummer: Pt 19, Seiten: 3479 - 3486
Laube T, Schanze T, Brockmann C, Bolle I, Stieglitz T, Bornfeld N
Chronically Implanted Epidural Electrodes in Minipigs Allow Function Test of Epiretinal Implants
2003 Graef Arch Clin Exp, Band: 241, Seiten: 1013 - 1019
Stieglitz T, Schuettler M, Schneider A, Valderrama E, Navarro X
Non-invasive Measurement of Torque Development in the Rat'’s Foot during Electrical Stimulation: Measurement Setup and First Results from Acute Stimulation of the Sciatic Nerve with Polyimide-Based Cuff Electrodes
2003 Ieee T Neur Sys Reh, Band: 11, Nummer: 4, Seiten: 427 - 437

2002

nach oben zur Jahresübersicht

Stieglitz T, Ruf HH, Gross M, Schuettler M, Meyer JU
A Biohybrid System to Interface Peripheral Nerves after Traumatic Lesions: Design of a High Channel Sieve Electrode
2002 Biosens Bioelectron, Band: 17, Seiten: 685 - 696
Stieglitz T, Gross M
Flexible BIOMEMS with Electrode Arrangements on Front and Back Side as Key Component in Neural Prostheses and Biohybrid Systems
2002 Sensor Actuat B-chem, Band: B83, Seiten: 8 - 14
Stieglitz T
Implantable Microsystems for Monitoring and Neural Rehabilitation. Part II
2002 Medical Device Technology, Band: 13, Nummer: 1, Seiten: 24 - 27
Gross M, Altpeter D, Stieglitz T, Schuettler M, Meyer JU
Micromachining of Flexible Neural Implants with Low-Ohmic Wire Traces Using Electroplating
2002 Sensor Actuat A-phys, Band: A96, Seiten: 105 - 110
Ceballos D, Valero A, Valderrama E, Schuettler M, Stieglitz T, Navarro X
Morphological and Functional Evaluation of Peripheral Nerve Fibers Regenerated through Polyimide Sieve Electrodes over Long-Term Implantation
2002 J Biomed Mater Res A, Band: 60, Nummer: 4, Seiten: 517 - 528

2001

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Stieglitz T
Flexible Biomedical Microdevices with Double-Sided Electrode Arrangements for Neural Applications
2001 Sensor Actuat A-phys, Band: 90, Seiten: 203 - 211
Meyer JU, Stieglitz T, Scholz O, Haberer W, Beutel H
High Density Interconnects and Flexible Hybrid Assemblies for Active Biomedical Implants
2001 Ieee T Adv Packaging, Band: 24, Nummer: 3, Seiten: 366 - 374
Stieglitz T
Implantable Microsystems for Monitoring and Neural Rehabilitation. Part I
2001 Medical Device Technology, Band: 12, Nummer: 12, Seiten: 16 - 21
Klinge PM, Vafa MA, Brinker T, Brandes A, Walter GF, Stieglitz T, Samii M, Wewetzer K
Molecular Characterization of Axonal Sprouting and Tissue Changes after Long-term Implantation of a Polyimide Sieve Electrode to the Transsected Adult Rat Sciatic Nerve
2001 Biomaterials, Band: 22, Nummer: 17, Seiten: 2333 - 2343
Heiduschka P, Romann I, Stieglitz T, Thanos S
Perforated Microelectrode Arrays Implanted in the Regenerating Adult Central Nervous System
2001 Exp Neurol, Band: 171, Nummer: 1, Seiten: 1 - 10
Navarro X, Valderrama E, Stieglitz T, Schuettler M
Selective Fascicular Stimulation of the Rat Sciatic Nerve with Multipolar Polyimide Cuff Electrodes
2001 Restor Neurol Neuros, Band: 18, Nummer: 1, Seiten: 9 - 21

2000

nach oben zur Jahresübersicht

Stieglitz T, Beutel H, Schuettler M, Meyer JU
Micromachined, Polyimide-based Devices for Flexible Neural Interfaces
2000 Biomed Microdevices, Band: 2, Nummer: 4, Seiten: 283 - 294
Rodriguez FJ, Ceballos D, Schüttler M, Valderrama E, Stieglitz T, Navarro X
Polyimide Cuff Electrodes for Peripheral Nerve Stimulation
2000 J Neurosci Meth, Band: 98, Nummer: 2, Seiten: 105 - 118
Stieglitz T, Beutel H, Meyer JU
‘Microflex‘ A New Assembling Technique for Interconnects
2000 J Intel Mat Syst Str, Band: 11, Nummer: 6, Seiten: 417 - 426

1999

nach oben zur Jahresübersicht

Thielecke H, Stieglitz T, Beutel H, Matthies T, Ruf HH, Meyer JU
Fast and Precise Positioning of Single Cells on Planar Electrode Substrates
1999 Ieee Eng Med Biol, Band: 18, Nummer: 6, Seiten: 48 - 52
Stieglitz T, Meyer JU
Implantable Microsystems: Polyimide-Based Neuroprostheses for Interfacing Nerves
1999 Medical Device Technology, Band: 10, Nummer: 6, Seiten: 28 - 30
Plachta D, Morgans J, Bleckmann H
Responses of Midbrain Lateral Line Units of Goldfish, Carassius Auratus, to Constant-Amplitude and Amplitude-Modulated Water Wave Stimuli.
1999 J Comp Physiol A, Band: 185, Seiten: 405 - 417
KurzfassungResponses of mechanosensory lateral line units to constant-amplitude hydrodynamic stimuli and to sinusoidally amplitude-modulated water movements were recorded from the goldfish (Carassius auratus) torus semicircularis. Responses were classified by the number of spikes evoked in the unit's dynamic range and by the degree of phase locking to the carrier- and amplitude-modulation frequency of the stimulus. Most midbrain units showed phasic responses to constant-amplitude hydrodynamic stimuli. For different units peri-stimulus time histograms varied widely. Based on iso-displacement curves, midbrain units prefered either low frequencies (≤33 Hz), mid frequencies (50–100 Hz), or high frequencies (≥200 Hz). The distribution of the coefficient of synchronization to constant-amplitude stimuli showed that most units were only weakly phase locked. Midbrain units of the goldfish responded to amplitude-modulated water motions in a phasic/tonic or tonic fashion. Units highly phase locked to the amplitude modulation frequency, provided that modulation depth was at least 36%. Units tuned to one particular amplitude modulation frequency were not found.

1998

nach oben zur Jahresübersicht

Navarro X, Calvet S, Rodriguez FJ, Stieglitz T, Blau C, Buti M, Valderrama E, Meyer JU
Stimulation and Recording from Regenerated Peripheral Nerves through Polyimide Sieve Electrodes
1998 J Peripher Nerv Syst, Band: 3, Nummer: 2, Seiten: 91 - 101

1997

nach oben zur Jahresübersicht

Stieglitz T, Beutel H, Meyer J U
A flexible, light-weighted, multichannel sieve electrode with integrated cables for inter¬facing regenerating peripheral nerves
1997 Sensor Actuat A-phys, Band: 60, Nummer: 1-3, Seiten: 240 - 243
Blau A, Ziegler C, Heyer M, Schwitzgebel G, Matthies T, Stieglitz T, Meyer J U, Jung G, Kienle S, Göpel W
Characterization and Optimization of Microelectrode Arrays for In-vivo Nerve Signal Recording and Stimulation
1997 Biosens Bioelectron, Band: 12, Nummer: 9-10, Seiten: 883 - 892

Reviews/Übersichtsartikel in wissenschaftlichen Fachzeitschriften

Jahre: 2017 | 2015 | 2011

zurück zur Übersicht aller Publikationen

2017

nach oben zur Jahresübersicht

Alt M, Fiedler E, Rudmann L, Ordonez J, Ruther P, Stieglitz T
Let There Be Light — Optoprobes for Neural Implants
2017 P Ieee, Band: 105, Nummer: 1, Seiten: 101 - 138
KurzfassungOver the past decades, optical technologies have entered neural implant technologies. Applications such as optogenetics, near-infrared spectroscopy (NIRS), and direct-near-infrared stimulation (NIS) request technical devices that combine electrical and optical recording as well as stimulation capabilities using light sources and/or optical sensors. Optoprobes are the technical devices that meet these requirements. This paper provides basic insights into optogenetic mechanisms, the background of NIRS and NIS, and focuses on fundamental requirements of technical systems from a biological background. The state of the art of optoprobes is reviewed and attention is drawn on the potential long-term stability of these technical devices for chronic neural implants. Further, material selection for stiff and flexible devices, applicable light sources, waveguide and coupling concepts, packaging paradigms as well as system assembly and integration aspects are discussed in view of biocompatible and biostable devices. This paper also considers the physical background of light scattering and heat generation when light sources are implanted into biological tissue.

2015

nach oben zur Jahresübersicht

Pasluosta CF, Gassner H, Winkler J, Klucken J, Eskofier BM
An Emerging Era in the Management of Parkinson's Disease: Wearable Technologies and the Internet of Things.
2015 Ieee J Biomed Health, Band: 19, Nummer: 6, Seiten: 1873 - 1881

2011

nach oben zur Jahresübersicht

Jensen W, Micera S, Navarro X, Stieglitz T, Guiraud D, Divoux J, Rossini PM, Yoshida K
Transverse Intrafascicular Multichannel Electrode (TIME) system for induction of sensation and treatment of phantom limb pain in amputees, Position paper
2011 5th Concertation and Consultation Workshop of projects in Micro-Nano-Bio convergence Systems (MNBS)
Bucher V, Bunge A, Clasbrummel B, Hauser J, Klein S, Köhler F, Kubon M, Lehmann M, Lenarz T, Mokwa W, Nestler B, Schmnieder R, Stlezle M, Stett A, Stieglitz T, Ulbricht M, Urban GA, Weiller C, Wildau H-J, Woias P, Wrobel W-G
VDE-Positionspapier Theranostische Mikro-/Nano-Implantate
2011 VDE-Positionspapier

Monographien

Jahre: 2005

zurück zur Übersicht aller Publikationen

2005

nach oben zur Jahresübersicht

VDE-Verlag
VDE-Studie zum Anwendungsfeld Neuroprothetik – Mikrosysteme in der Medizin
Bolz A, Dehm J, Hahn A, Hoffmann KP, Hofmann U, Koch KP, Lenarz T, Meindl RC, Reuter G, Rosahl SK, Rolf A, Scheider H, Stieglitz T, Wildau JH

Buchbeiträge

Jahre: 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 1998

zurück zur Übersicht aller Publikationen

2016

nach oben zur Jahresübersicht

Plachta DT
Inferior Colliculus Approach in a Rat
In: Experimental Neurosurgery in Animal Models
2016, Humana Press, Janowski, Miroslaw, Seiten: 73 - 84, Janowski, Miroslaw, ISBN: 978-1-4939-3728-8
KurzfassungThe inferior colliculus (IC) of the rat is a well-investigated and understood model for topographical mapping of the frequency domain (Clopton et al., Exp Neurol 42(3):532-540, 1974; Kelly and Masterton, J Comp Physiol Psychol 91(4): 930-936, 1977; Borg, Hear Res 8(2) 101-115, 1982; Ryan et al., Hear Res 36(2-3): 181-189, 1988; Zhang et al., Hear Res 117(1-2):1-12, 1998). As a central hub for binaural auditory processing in the midbrain (Du et al., Eur J Neurosci 30(9): 1779-1789, 2009) it shows a variety of response patterns to a given complex auditory stimulation (Kelly et al., Hear Res 56(1-2):273-280, 1991; Kelly and Li, Hearing Res 104:112-126, 1997). It is therefore a major target for neuroscientific approaches of the ascending and descending auditory pathway. Approaching the IC is, however, not only valuable for scientists interested in auditory processing, but also for students learning the proceedings of standard electrophysiological experimentation. In addition, engineers of biomedical devices (e.g., flexible penetrating electrodes) can take benefit from the IC approach (Kisban et al., Conference proceedings: annual international conference of the IEEE Engineering in Medicine and Biology Society IEEE Engineering in Medicine and Biology Society Conference, 2007:175-178). A critical test of the suitability of shaft electrodes is their successful implantation in vivo. The steady tonotopic structure of the IC and its three subdivisions provides an almost perfect anatomic testing ground (Saldana and Merchan, J Comp Neurol 319(3):417-437, 1992). Additionally, the anatomical procedure to access the IC requires only a medium level of surgical skills and the testing apparatus can be kept relatively small and manageable. The current study describes the necessary anatomical steps and materials needed for the aforementioned scenarios.

2015

nach oben zur Jahresübersicht

Asplund M
Degradable conjugated conducting polymers and nerve guidance
In: Biosynthetic Polymers for Medical Applications
2015, Woodhead Publishing, Elsevier Group, L. Poole-Warren, P. Martens and R. Green, Seiten: 299 - 330, L. Poole-Warren, P. Martens and R. Green, ISBN: 9781782421054
KurzfassungBiosynthetic Polymers for Medical Applications provides the latest information on biopolymers, the polymers that have been produced from living organisms and are biodegradable in nature. These advanced materials are becoming increasingly important for medical applications due to their favorable properties, such as degradability and biocompatibility. This important book provides readers with a thorough review of the fundamentals of biosynthetic polymers and their applications. Part One covers the fundamentals of biosynthetic polymers for medical applications, while Part Two explores biosynthetic polymer coatings and surface modification. Subsequent sections discuss biosynthetic polymers for tissue engineering applications and how to conduct polymers for medical applications.
Pasluosta CF, Chiu AW
Modulation of grasping force in prosthetic hands using neural network-based predictive control.
In: Artificial Neural Networks: Second Edition
2015, Methods Mol Biol, Seiten: 179 - 194,
Stieglitz T
Nicht nur Schrauben und Muttern - Wissen in den Ingenieur¬wissenschaften
In: Wissen
2015, Rombach, Eickhoff F.C., Seiten: 121 - 135, Eickhoff F.C., ISBN: 978-3-7930-9811-9

2014

nach oben zur Jahresübersicht

Stieglitz T, Hofman U, Rosahl S K
Neurotechnik
In: Biomedizinische Technik – Band 1: Faszination, Einführung, Überblick.
2014, Walter de Gruyter, Morgenstern U., Kraft. M., Seiten: 441 - 466, Morgenstern U., Kraft. M.,

2013

nach oben zur Jahresübersicht

Schüttler M, Stieglitz T
Assembly and Packaging
In: Intelligent Implantable Sensor Systems for Medical Applications
2013, Woodhead Publishing, Hodgins, D., Inmann, A., Seiten: 108 - 149, Hodgins, D., Inmann, A.,
Stieglitz T, Schüttler M
Implant Interfaces
In: Intelligent Implantable Sensor Systems for Medical Applications
2013, Woodhead Publishing, Hodgins, D., Inmann, A., Seiten: 39 - 67, Hodgins, D., Inmann, A.,

2012

nach oben zur Jahresübersicht

Stieglitz T
Electrodes
In: Handbook on Neural Activity Measurement
2012, Oxford University Press, Brette, R., Destexhe, A., Seiten: 8 - 43, Brette, R., Destexhe, A.,
Henle C, Schuettler M, Rickert J, Stieglitz T
Towards Electrocorticographic Electrodes for Chronic Use in BCI Applications
In: Towards Practical Brain-Computer-Interfaces
2012, Electrocorticograms (ECoG) have been originally used for presurgical , Nummer: 4, Seiten: 75 - 96,

2011

nach oben zur Jahresübersicht

Kraft M, Stieglitz T, Leiss R
Editorial: Innovative Aids in Rehabilitation and in the Disabled
In: Innovative Aids in Rehabilitation and in the Disabled
2011, IGE print,
Stieglitz T
Gehirn-Computer-Schnittstellen: Technische Grundlagen und praktische Anwendungen im Überblick
In: Die Zukunft des menschlichen Gehirns-Ethische und anthropologische Herausforderungen der modernen Neurowissenschaften
2011, Institut für Kirche und Gesellschaft,

2009

nach oben zur Jahresübersicht

Stieglitz T, Rubehn B, Henle C, Kisban S, Herwik S, Ruther P, Schüttler M
Brain-Computer Interfaces: An Overview of the Hardware to Record Neural Signals from the Cortex
In: Neurotherapy - Progress in Restorative Neuroscience and Neurology
2009, Elsevier, Verhaagen, J., Hol, E. M., Huitinga, I., Wijnhold, J., Bergen, A. B., Boer, G. J., Swaab, D. F., Seiten: 297 - 315, Verhaagen, J., Hol, E. M., Huitinga, I., Wijnhold, J., Bergen, A. B., Boer, G. J., Swaab, D. F.,
Stieglitz T
Technische Anforderungen an Neuroimplantate
In: Das technisierte Gehirn-Neurotechnologien als Herausforderung für Ethik und Anthropologie
2009, Mentis Verlag, Müller, O., Clausen, J., Maio, G., Seiten: 23 - 33, Müller, O., Clausen, J., Maio, G.,

2008

nach oben zur Jahresübersicht

Stieglitz T
Neuroprothesen als Schnittstelle zum peripheren und zentralen Nervensystem – Ein- und Aussichten aus dem Blickwinkel der biomedizinischen Technik
In: Die “Natur des Menschen” in Neurowissenschaft und Neuroethik
2008, Könighausen & Neumann, Clausen, J., Müller, O., Maio, G., Seiten: 59 - 77, Clausen, J., Müller, O., Maio, G.,

2007

nach oben zur Jahresübersicht

Meyer JU, Stieglitz T
Adaptronic Systems in Medicine and Medical Technology
In: Adaptronics and Smart Structures
2007, Springer-Verlag, Seite: in press,
Stieglitz T
Neural Prostheses in Clinical Practice: Biomedical Microsysteme in Neurological Rehabilitation
In: Operative Neuromodulation. Acta Neurochir. Suppl.
2007, Springer-Verlag, Sakas, D.E., Simpson, B., Krames, E., Seite: in press, Sakas, D.E., Simpson, B., Krames, E.,
Stieglitz T
Restoration of Neurological Functions by Neuroprosthetic Technologies: Future Prospects and Trends towards Micro-, Nano- and Biohybrid Systems
In: Operative Neuromodulation. Acta Neurochir. Suppl.
2007, Springer-Verlag, Sakas, D.E., Simpson, B., Krames, E., Seite: in press, Sakas, D.E., Simpson, B., Krames, E.,

2006

nach oben zur Jahresübersicht

Stieglitz T, Meyer JU
Biomedical Microdevices for Neural Implants
In: BIOMEMS
2006, Springer-Verlag, Urban, G. A., Seiten: 71 - 138, Urban, G. A.,
Stieglitz T, Meyer JU
Neural Implants in Clinical Practice
In: BIOMEMS
2006, Springer-Verlag, Urban, G. A., Seiten: 41 - 70, Urban, G. A.,

2005

nach oben zur Jahresübersicht

Stieglitz T
Development of a Micromachined Epiretinal Vision Prosthesis
In: Artificial Sight
2005, Springer-Verlag, Seite: submitted,

2004

nach oben zur Jahresübersicht

Stieglitz T
Electrode Materials for Recording and Stimulation
In: NEUROPROSTHETICS: Theory and Practice
2004, World Scientific Publishing, Horch, K., Dhillon, G., Seiten: 471 - 516, Horch, K., Dhillon, G.,

1998

nach oben zur Jahresübersicht

Stieglitz T, Meyer J U
Microtechnical Interfaces to Neurons
In: Microsystem Technology in Chemistry and Life Science (Topics in Current Chemistry Series)
1998, Springer, Manz, A., Becker, H., Seiten: 131 - 162, Manz, A., Becker, H.,

Vorträge

Jahre: 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 1998 | 1997 | 1993

zurück zur Übersicht aller Publikationen

2019

nach oben zur Jahresübersicht

Stieglitz T
Flexible Multielectrode Arrays as Implantable Interface to the Central and Peripheral Nervous System.
2019 Department of Biomedical Engineering, University of Basel

2018

nach oben zur Jahresübersicht

Johnston M, Böhm T, Joseph K, Asplund M, Hofmann UG, Thiele S, Stieglitz T, Haas CA
QUANTIFY – a semi-automated quantification of the CNS immune response at the probe-tissue-interface.
2018 Society for Neuroscience Meeting, Nov. 3rd-7th, 2018, San Diego, Ca, USA
Pfau J, Ganatra D, Weltin A, Urban G, Kieninger J, Stieglitz T
Electrochemical Stability of Thin-Film Platinum as Suitable Material for Neural Stimulation Electrodes.
2018 52nd Annual Conference of the German Society for Biomedical Engineering, DGBMT“ , Aachen, 26.09-28.09.18
Pasluosta C, Kiele P, Stieglitz T
Eliciting somatosensory percepts via multi-channel wireless electrical stimulation of afferent nerves .
2018 2018 52nd Annual Conference of the German Society for Biomedical >Engineering, DGBMT" , Aachen, 26.09-28.09.18
Pasluosta C, Kiele P, Stieglitz T
Toward a Multi-Channel Wireless System for Electrical Stimulation of Peripheral Nerves: Modelling and Simulation of Signal Transmission.
2018 22nd Annual Conference of the International Functional Electrical Stimulation Society, IFESS" , Nottwil, 28.08-31.08.18
Stieglitz T
Stability of materials and flexible neural probes for recording, electrical and optical stimulation.
2018 Colloquium des SFB 889 "Cellular Mechanisms of Sensory Processing", Universitätsmedizin Göttingen, 19.06.2018, Göttingen
Stieglitz T
Introduction to Optogenetics.
2018 Fachgruppe Intelligente Implantate, microTEC Südwest, 16.05.2018, Rottweil (2018)
Stieglitz T
Stability and Functionality of Thin-film Recording and Stimulation Electrodes in the Peripheral and Central Nervous System.
2018 International Conference on Advanced Neurotechnologies (ICAN), May 6-8, 2018, Ann Arbor, MI, USA
Stieglitz T
Bioelektronische Medizin-Versprechen und Herausforderungen.
2018 microTEC Südwest Clusterkonzerenz 2018, 16.-17.04.2018, Konzerthaus Freiburg
Stieglitz T
Neurostimulation zur Wiederherstellung sensorischen Feedbacks.
2018 MedTech Summit, 11.-12.04.2018, Messe Nürnberg
Stieglitz T
When technology hits the nerve-intelligent implants in neurological treatment and rehabilitation.
2018 XPOMET, Die Convention für Innovation und Hightech in der Medizin, 21.-23.03.2018, Leipzig
Stieglitz T
“Wenn Technik den Nerv trifft… Miniaturisierte Implantate in der Neurotechnik und für Elektrozeutika”
2018 Fachtagung Kunststoff trifft Medizintechnik, 31.01.-01.02.2018, Leipzig (2018).
Stieglitz T
Bioelektronische Medizin‑Versprechen und Herausforderungen
2018 Hochrhein-Seminar, Technisches Gymnasium Waldshut
Boehler C, Kleber C, Oberueber F, Asplund M
Electroactive coatings as a strategy to improve the longevity of neuroelectronic devices.
2018 Gordon Research Conference on Neuroelectronic Interfaces, 25.-30.03.2018, Galveston, TX, USA
Kirsch M, Böhm T, Joseph K, Asplund M, Hofmann UG, Thiele S, Stieglitz T, Haas CA
Molecular and structural characterization of probe-tissue interactions in the rat brain.
2018 Gordon Research Conference on Neuroelectronic Interfaces, 25.-30.03.2018, Galveston, TX, USA
Boehler C, Asplund M
Nanostructured Pt as a high performance coating for neural interfaces
2018 Micro Alliance Workshop 2018, October 4-5, 2018, Freiburg, Germany
Boehler C, Asplund M
Nanostructured platinum as a high performance coating for neural interfaces with excellent stability and biocompatibility.
2018 International Conference on Advanced Neurotechnologies (ICAN), May 6-8, 2018, Ann Arbor, MI, USA
Vomero M, Zuchini E, Gueli C, Delfino E, Ashouri D, Carli S, Fadiga L, Stieglitz T
Performance Evaluation of Glassy Carbon Electrodes for Neural Applications Based on Different Diameters.
2018 Gordon Research Conference on Neuroelectronic Interfaces, 25.-30.03.2018, Galveston, TX, USA
Stieglitz T, Müller M, Boretius T, Micera S, Granata G, Rossini PM, Cvancara P
Stability of miniaturized neural interfaces.
2018 Gordon Research Conference on Neuroelectronic Interfaces, 25.-30.03.2018, Galveston, TX, USA
Boehler C, Schopf A, LealOrdonez J, Asplund M
Super-Capacitive Conducting Polymer Electrodes Can Control Cell Migration Via DC Stimulation.
2018 ”, 40th International Conference of the IEEE Engineering in Medicine and Biology Society, 17.-21.07.2018, Oahu, Hawaii, USA
Böhm T, Joseph K, Kirsch M, Moroni R, Hilger A, Manke I, Johnston M, Asplund M, Vomero M, Hofmann UG, Stieglitz T, Haas CA, Thiele S
X-ray tomographic 3D reconstruction of the brain-probe-interface in rat cortex.
2018 Gordon Research Conference on Neuroelectronic Interfaces, 25.-30.03.2018, Galveston, TX, USA

2017

nach oben zur Jahresübersicht

Stieglitz T
Bioelektronische Medizin‑Versprechen und Herausforderungen
2017 Heidelberger Kolloquium Medizinische Biometrie, Informatik und Epidemologie, Universitätsklinikum Heidelberg
Stieglitz T, Cvancara P, Müller M, Liljemalm R, Erhardt J, Boehler C, Ashouri D, Vomero M, Oliveira A, Eickenscheidt M, Asplund M, Ordonez JS
Miniaturized Neural Implants: Design, Development and Reliability
2017 Designs of Medical Devices Conference Europe 2017, 14.-15.11.2017, Einthoven, The Netherlands (2017).
Pasluosta C, Kiele P, Resch A, Stieglitz T
Restoring natural sensory feedback in amputees via electrical stimulation after targeted muscle reinnervation
2017 Meeting of the Society for Neuroscience
Stieglitz T, Cvancara P, Vomero M, Pfau J, Ashouri Vajari D, Oliveira A, Ordonez JS, Gueli C, Eickenscheidt M, Kassegne S
Stability and functionality of flexible electrodes arrays
2017 IEEE Brain Sensors Workshop, Glasgow, UK
Stieglitz T
Miniaturized Implants to Interface with the Peripheral and Central Nervous System.
2017 Center for Neuroprosthetics Seminar, École polytechnique fédérale de Lausanne, CH
Steib S, Klamroth S, Gassner H, Pasluosta C, Eskofier B M, Pfeifer K, Winkler J, Klucken J
Laufbandtraining mit Perturbation verbessert die Gang- und Gleichgewichtskontrolle bei Parkinsonpatienten: Eine randomisiert-kontrollierte Pilotstudie
2017 23th Sportwissenschaftlicher Hochschultag der Deutschen Vereinigung für Sportwissenschaft
Gassner H, Steib S, Klamroth S, Pasluosta C, Eskofier B M, Pfeifer K, Winkler J, Klucken J
Perturbation treadmill training improves motor symptoms, gait and postural stability in Parkinson’s disease: a randomized controlled pilot study
2017
Eickenscheidt M, Eberhardt J, Stieglitz T
Towards electrochemical noise analysis of electrode/electrolyte interfaces in vivo.
2017 Annual Meeting of the IFESS 2017, Rehab Week 10.- 20.07.2017, London, UK
Čvančara P, Sharmin N, Stieglitz T
Influence of Different Plasma Activation Treatments on Polyimide Thin-Film Electrodes
2017 Annual Meeting of the IFESS 2017, Rehab Week 10.- 20.07.2017, London, UK
Čvančara P, Boretius T, Guiraud D, Guiho T, Lopez-Alvarez V, Navarro X, Stieglitz T
On biocompatibility and stability of transversal intrafascicular multichannel electrodes – TIME
2017 Annual Meeting of the IFESS 2017, Rehab Week 10.- 20.07.2017, London, UK
Stieglitz T
Aktive Neuroimplantate
2017 Gesundheitskongress 2017, Gesundheitsnetzwerk Schwarzwald-Baar, Hochschule Furtwangen, Furtwangen
Buil J, Müller M, Mielke D, Stieglitz T, Scherberger H
Investigating peripheral nervous system interfaces for somatosensory stimulation.
2017 Neuroscience Society Meeting in Göttingen, 23.03.2017
Stieglitz T
Is this me ? Interfaces with the nervous system control prostheses and treat diseases and disorders
2017 Séminaire «Corps et prothèses : vécus, usages, contextes», Séance 1: «Vulnérabilité et capabilité, Université de Strasburg, Frankreich
Stieglitz T
Prüfverfahren für hermetische und nicht-hermetische Implantat-Komponenten
2017 Fachgruppe Intelligente Implantate, MicroTEC Südwest, Ulm
Stieglitz T
Why Neurotechnologies? About the Purposes for Developing Clinical Applications of Neurotechnologies
2017 Mechanized Brains, Embodied Technologies, Restored Movements. Phlosophical and Ethical Implications of Neurotechnological Interventions., Freiburg Institute of Advanced Studies, Freiburg

2016

nach oben zur Jahresübersicht

Cvancara P
Flexible Neural Interfaces in Fundamental and Translational Research
2016 Nanoscience Institute for Medical and Engineering Technology (NIMET), University of Florida, USA
Stieglitz T
Different Applications but Similar Technologies and Same Challenges in Neural Implants
2016 GOSTRALIA! Networking Research Symposium, Research Landscapes and Technology Transfer in Australia and Baden-Wuerttemberg-Current Projects and Perspectives for Research Collaboration, Stuttgart, Deuts
Asplund M, Boehler C, Oberueber F, Heizmann S, Kleber K, Hassarati R, Schopf A
How to get PEDOT on your neural electrodes: reliable, functionalized and homogenously coated
2016 Society for Neuroscience meeting 2016, San Diego, Nov 12-16 2016, USA
Stieglitz T
Thin-film electrodes to interface with the nervous system
2016 The Üssur and Ottobuck Treaty on Neural Controlled Man-Machine Interface, Reykjavik, Iceland, 2016
Kanzler C, Lee S, Daneault J, Golabchi F, Hannink J, Pasluosta C, Eskofier B M, Bonato P
Home Monitoring of Drug Response in Patients with Parkinson’s Disease using Wearable Sensors
2016 Wireless Health 2016 of the IEEE Engineering in Medicine and Biology Society
Stieglitz T
Development, prototyping, fabrication and testing individualized long-term safe electrode arrays.
2016 Workshop on Brain-Machine Interface, 3rd International Conference on NeuroRehabilitation, Segovia, Spain
Pasluosta C, Steib S, Klamroth S, Gassner H, Hannink J, von Tscharner V, Pfeifer K, Winkler J, Klucken J, Eskofier B M
Motor Output Complexity in Parkinson's disease Patients during Acute Treadmill Intervention
2016 International Symposium on the Neuromechanics of Human Movement
Pasluosta C, Steib S, Klamroth S, Gassner H, Hannink J, von Tscharner V, Pfeifer K, Winkler J, Klucken J, Eskofier B M
Changes in Motor Output Complexity during Acute Treadmill Intervention on Parkinson’s disease Patients
2016 11th joint Conference on Motor Control & Learning, Biomechanics & Training
Gassner H, Schlachetzki J, Marxreiter F, Kohl Z, Barth J, Goßler J, Reinfelder S, Pasluosta C, Winkler J, Eskofier B M, Klucken J
Wearable sensors provide objective gait parameters correlating to clinical scores in Parkinson’s disease
2016 89th Congress of the Deutschen Gesellschaft für Neurologie mit Fortbildungsakademie (DGN)
Bentler C, Stöcklin S, Stieglitz T
Blueprint for implantable Brain Computer Interfaces made of commercial off-the-shelf components
2016 NANS- NIC Joint Meeting, 25.-29-06.2016, Baltimore, MD, USA
Boehler C, Stieglitz T, Asplund M
Nanostructured platinum – a competitive material for neural stimulation and recording
2016 NANS-NIC Neural Interfaces Conference, June 25-29, 2016, Baltimore, USA
Kleber C, Boehler C, Lienkamp K, Rühe J, Asplund M
A photo-patternable and conductive hydrogel with covalent attachement to microelectrodes
2016 10th World Biomaterials Congress, May 17-22, 2016, Montréal, Canada
Heizmann S, Kilias A, Ruther P, Egert U, Asplund M
Dye delivery from PEDOT electrodes in vivo - A new concept to reconstruct recording sites
2016 International Conference for Advanced Neurotechnology (ICAN), Ann Arbor, Michigan, USA
Heizmann S, Kilias A, Ruther P, Egert U, Asplund M
Precise neurotracer delivery on chip
2016 European Material Research Society (EMRS), Lille, France, May 02-06, 2016
Boehler C, Kleber C, Martini N, Xie Y, Hofmann U G, Stieglitz T, Asplund M
Anti-inflammatory coatings on flexible neural probes in the cortex: A chronic in vivo study
2016 10th World Biomaterials Congress, May 17-22, 2016, Montréal, Kanada
Hassarati R, Foster J, Asplund M, Green R
Electrical stimulation of cells in living bioelectronic devices
2016 10th World Biomaterials Congress, May 17-22, 2016, Montréal, Canada
Kleber C, Böhler C, Lienkamp K, Rühe J, Asplund M
A photo-patternable and conductive hydrogel with covalent attachment to microelectrodes
2016 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016
Erhardt JB, Stieglitz T
Solution or Elusion? What Purpose does a Head Wrap serve during Cochlear-Implant-Patient MRI?
2016 Conference of European Society for Magnetic Resonance in Medicine and Biology (2016)

2015

nach oben zur Jahresübersicht

Pasluosta C, Barth J, Gassner H, Winkler J, Klucken J, Eskofier B M
Postural Instability Inference in Parkinson's Disease Patients Using Wearable Sensors
2015 88th Congress of the Deutschen Gesellschaft für Neurologie mit Fortbildungsakademie (DGN)
Clausen, J, Stieglitz, T
Darf Technik den Nerv treffen? - Ein Streitgespräch
2015 BMBF-Zukunftskongress Demografie Technik zum Menschen bringen, Berlin
Stieglitz T
Strom hilft heilen – Neurotechnik in Therapie und Rehabilitation
2015 RehabilitationLange Nacht der Wissenschaft, Universität Freiburg,
Stieglitz T
Strom hilft heilen – Neurotechnik in Therapie und Rehabilitation
2015 RehabilitationLange Nacht der Wissenschaft, Universität Freiburg,
Stieglitz T, Ordonez, J.S, Plachta, D.T.T, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M
Neural Interfaces – From Basic Research to Clinical Applications
2015 The US-Turkey Advanced Study Institute on Global Healthcare Challenges, Izmir, Türkei
Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M
Intelligente Implantate Chancen und Herausforderungen am Beispiel neuro-technischer Anwendungen
2015 Symposium Intelligente Implantate, Hochschule Furtwangen, Campus Villingen-Schwenningen,
Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M
Mikrosysteme im Kontakt mit dem Nervensystem - Chancen und Herausforderungen
2015 Naturwissenschaftliches und Medizinisches Institut (NMI) an der Universität Tübingen, Reutlingen
Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M
Neurotechnische Implantate im peripheren und zentralen Nervensystem
2015 Fakultät füt Elektro- und Informationstechnik, Technische Universität Dresden
Stieglitz T, Ordonez, J.S, Hassler, C, Fiedler, E, Ashouri, D, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M
Sensorik in der Medizintechnik am Beispiel neurotechnischer Implantate
2015 F&E Forum der Heraeus Precious Metals, Hanau
Erhardt JB,, Leupold, J, Fuhrer E, Gruschke O, Wapler MC, Henning J, Korvink J, Stieglitz T, Hennig, Jan Korvink, Thomas Stieglitz
Influence of Laser Structured Pt/Ir Brain Implant Electrodes with Trapezoidal Cross Section on MRI Artefact Size
2015 Material Research Society Fall meeting, Boston, Massachusetts, USA, 29.11. - 4.12. 2015
Erhardt JB, Kleber C, Leupold J, Fuhrer E, Asplund M, Hennig J, Korvink JG, Stieglitz T, Korvink, T. Stieglitz
MRI artefact comparison of electrode structures made of Pt/Ir and the conducting polymer PEDOT.
2015 European Society of Magnetic Resonance in Medicine and Biology 2015 Congress. 1–3 October 2015. Edinburgh, United Kingdom
Erhardt JB, Vomero M, Gruschke OG, Leupold J, Wapler MC, Hennig J, Korvink JG, Stieglitz T
NEUMARE
2015 Nobel Laureate Meeting Lindau 2015
Leupold J, Erhardt J, Köhler S,, Wick M, Hennel F, Hennig J
On the phase and T2* properties of the DESS sequence.
2015 European Society of Magnetic Resonance in Medicine and Biology 2015 Congress. 1–3 October 2015. Edinburgh, United Kingdom
Fuhrer E, Gruschke O, Leupold J, Erhardt JB, Göbel K, Wapler MC, Stieglitz T, Wallrabe U, Henning J, Korvink JG
Susceptibility artefacts of thin film platinum electrodes.
2015 International Conference on Magnetic Resonance Microscopy, 2.-6.8.2015, München

2014

nach oben zur Jahresübersicht

Stieglitz, T
Vom Impuls zur Neuromodulation
2014 10. Jahrestagung der deutschen Gesellschaft für Neuromodulation - Bad Oeynhausen
Stieglitz T, Ordonez, J.S, Henle, C, Meier, W, Hassler, C, Fiedler, E, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Ball, T, Rickert, J, Cvancara, P, Schuettler, M
Miniaturized neural interfaces and implants in fundamental and translational research
2014 Institute of Biomaterials and Biomedical Engineering, University of Toronto
Stieglitz, T
Fühlende Prothesen - von der Prothetik zur Neuroprothetik.
2014 Innovationsforum Medizintechnik Tuttlingen
Stieglitz T
Neurotechnische Mensch-Maschine Schnittstellen -Fiktion oder klinische Praxis?
2014 Innovationsforum Medizintechnik
Stieglitz, T, Ordonez, J.S, Henle, C, Meier, W, Hassler, C, Fiedler, E, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Schuettler, M
Miniaturized Neural Interfaces and Implants in Neurological Rehabilitation
2014 2nd International Conference on Neural Rehabilitation (ICNR), Plenary talk, Aalborg
Stieglitz T
Neuroimplantate-Technische Systeme an der Material-Gewebe-Schnittstelle
2014 18. Berliner Colloquium der Daimler und Benz Stiftung mit dem Thema "Mensch-Maschine-Visionen", Berlin
Stieglitz, T, Plachta, D.T.T., Giertmuehlen, M, Boretius, T, Rubehn, B, Henle, C, Meier, W, Kohler, F, Fiedler, E, Hassler, C, Ordonez, J.S, Rickert, J, Zentner, J, Schuettler, M
Neural Prostheses- today and tomorrow
2014 Weltkongress für Othopädietechnik und Rehabilitation, Leipzig
Pasluosta C, Kuban B, Niebauer M
Development of a Decision Support System for Cardiac Resynchronization Therapy Patient Candidacy using Discrete Wavelet Transform and Support Vector Machine
2014 14th Biennial Meeting of the International Society for Applied Cardiovascular Biology
Boehler C, Heizmann S, Kleber C, Schopf A, Stieglitz T, Asplund M
Electroactive Functionalized Coatings: The next generation of PEDOT microelectrode systems
2014 DFG-NSF Workshop "New Perspectives on Neuroengineering and Neurotechnologie"

2013

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Stieglitz, T, Giertmuehlen, M, Cota, O, Plachta, D.T.T
Ansätze zur personalisierten Baroreflex-Stimulation
2013
Stieglitz T, Henle C, Meier W, Kohler F, Ordonez J, Rickert J, Schuettler M
From Prototypes to Approved Devices: Challenges to Setup a Production
2013 Symposium on Grand Challenges on Neurotechnology (SGCNT), Singapore
Stieglitz T, Rubehn B, Boretius T, Ordonez J, Schuettler M
Stability and Selectivity of PNS Interfaces
2013 Symposium on Grand Challenges on Neurotechnology (SGCNT), Singapore
Stieglitz T, Rubehn B, Boretius T, Henle C, Meier W, Kohler F, Fiedler E, Ordonez J, Rickert J, Schuettler M
Flexible Neural Probes in Fundamental and Translational Research
2013 International Conference on Biomedical Technology, Hannover, Germany.
Stieglitz T, Rubehn B, Henle C, Meier W, Kohler F, Fiedler E, Ordonez J, Schuettler M
ECoG Electrodes
2013 5th International Workshop on Advances in Electrocorticography, San Diego, USA
Stieglitz T
Miniaturized Neural Interfaces and Implants
2013 DEMOVE Symposium, Translational Engineering in Neurorehabilitation, Göttingen, Germany
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M
Miniaturized Neural Interfaces and Implants in Basic and Translational Research
2013 The US Turkey Advanced Study Institute on Global Healthcare Grand Challenges/ Adrasan, Turkey
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M
Electrodes and Implants for the Central Nervous System
2013 International Funtional Electrical Stimulation Society, Workshop on Implantable Neuroprostheses, San Sebastian, Spain
Stieglitz T
Gehirn-Computer-Schnittstellen auf dem Weg in die klinische Praxis
2013 e-Health Forum Freiburg
Stieglitz T, Boretius T, Ordonez J, Boehler C, Schuettler M
Intelligente Implantate
2013 Medtech-Biotech-Hightech: Medizinische Implantate. Helmholtz-Institut für Biomedizinische Technik der RWTH Aachen
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M
Neural Interfaces for Research Applications
2013 CSNE Technical Workshop: Microelectrode Technology, University of Washington, Seattle, USA
Stieglitz, T, Rubehn, B, Boretius, T., Henle, C, Ordonez, J, Meier, W, Hassler, C, Boehler, C, Kohler, F, Schuettler, M
Neural Interfaces for Research Applications
2013 CSNE Technical Workshop: Microelectrode Technology, University of Washington, Seattle, USA
Elixmann I, Ordonez J, Stieglitz T, Leonhardt S
In-Vitro Evaluation of a Drainage Catheter with Integrated Bioimpedance Electrodes to Determine Ventricular Size
2013 Proceedings of the Biomedical Microtechnology Conference
Fiedler E, Ordonez J, Stieglitz T
Laser-Structured Ceramic Adapters for Reliability Assembly of Flexible Thin-Film Electrodes
2013 Proceedings of the Biomedical Microtechnology Conference
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Boehler C, Kohler F, Schuettler M
Microtechnologies for Neural Implants
2013 1st Bernstein Sparks Workshop. Towards Long-Term Cortical Neuro-Interfaces, March 6-10, 2013, Delmenhorst, Germany.
Kohler F, Johannsen B, Haas N, Ordonez J, Stieglitz T, Schüttler M
The Influence of Flux on the Reliability of Solder-Sealed Hermetic Packages for Active Implantable Medical Devices
2013 Proceedings of the Biomedical Microtechnology Conference
Schüttler M, Huegle S, Ordonez J, Stieglitz T
Towards the Development of Implantable Connectors with High Contact Number
2013 IEE EMBS NER

2012

nach oben zur Jahresübersicht

Stieglitz T
Restorative Technologies
2012 University College Freiburg. Liberal Arts and Science Program
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler W, Boehler C, Kohler F, Schuettler M
Microtechnologies for Neural Implants
2012 Université de Montpellier II, Montpellier, France.
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Schuettler M
Microsystems in Neural Implants
2012 Max Planck Focus Meeting – Control and Learning in Micro-Systems / Saig-Lenzkirch

2011

nach oben zur Jahresübersicht

Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Schuettler M
Microimplants as interfaces to the nervous system
2011 McGovern Institute for Brain Research at MIT, Massachusetts Institute of Technology, Boston, USA
Stieglitz T
Die Gedanken im Griff“. Vortrag im Rahmen der Ringvorlesung „Ziele und Methoden der Neurotechnologie
2011 Albert-Ludwigs-Universität Freiburg
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Schuettler M
Advances in Neural Interfaces for the Peripheral and Central Nervous System Do Neural Interfaces have a Future ?
2011 3rd Annual Aalborg Symposium on the Advances in Neurophysiolgy and Neural Engineering of Movement
Stieglitz T
The technical side of neural interfaces
2011 PhD School Analysis and Models in Neural Physiology, Bernstein Center Freiburg
Stieglitz T
Von Prothesen und Implantaten
2011 AHA-Labor Kindergesundheitskongress, Zentrum für Kunst und Medientechnologien (ZKM), Karlsruhe
Stieglitz T
Retinal Prostheses & Neuroethics
2011 Pre-Conference Workshop on "Fundamentals of Functional Neuromodulation" at the 10th World Congress of the International Neuromodulation Society, London, UK
Stieglitz T, Henle C, Boretius T, Rubehn B, Meier W, Rickert J, Schuettler M
Miniaturisierte Neurotechnische Implantate
2011 Helmholtz-Symposium, Helmholtz-Institut, RWTH Aachen
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Schuettler M
Microsystems as Tools for Neural Implants
2011 IEEE EMBS Neural Engineering Conference, Plenary Talk
Stieglitz T, Henle C, Rubehn B, Meier W, Rickert J, Schuettler M
Ansätze zu miniaturisierten Gehirn-Computer-Schnittstellen für die Mensch-Maschine Kommunikation
2011 Deutsches Biosensor Symposium , Heilbad Heiligenstadt
Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Schuettler M
Microtechnologies for Neural Implants
2011 Melbourne, Australia, ICT for Life Science Forum
Stieglitz T, Rubehn B, Boretius T, Henle C, Meier W, Hassler C, Schuettler M
Microsystems as Tool to Interface the Brain
2011 Institute of Neurology, University College London, London, UK
Pasluosta C, Dua P
A Study of Co-expression Analysis of NFKBIA Gene Across the Hippocampal Tissue
2011 9th LBRN Annual Meeting

2010

nach oben zur Jahresübersicht

Stieglitz T
Gehirn-Computer-Schnittstellen: Technische Grundlagen und praktische Anwendungen im Überblick. Wenn Computer und Gehirn verschmelzen
2010 Die Technisierung des Menschen und ihre Konsequenzen, Evangelisches Forum, Kassel
Stieglitz T, Rubehn B, Boretius T, Henle C, Meier W, Schuettler M
Miniaturized Implants to Interface the Nervous System
2010 Promoting recovery in the injured central nervous system – Inauguration Symposium, Klinik für Paraplegiologie, Universitätsklinikum Heidelberg, Heidelberg
Pasluosta c, Chiu A W L
Evaluation of an Optimized Control Strategy for a Low-cost Prosthetic Hand
2010 2010 BMES Annual Fall Meeting
Stieglitz T
MST in der Neurotechnologie
2010 Neurotechnologie in Klinik und Forschung eine Bestandsaufnahme. FAM-Workshop, Freiburg
Fontana J M, Pasluosta C, Sellers E D, H Tims, Chiu A W L
Real-time Signal Classification, Predictive Model and Vibrotactile Feedback Control for a 5-digit Prosthetic Hand
2010 Louisiana Academy of Sciences (LAS) 84th Annual Meeting
Stieglitz T
Neural Interface Development at the Laboratory for Biomedical Mi-crotechnology
2010 Cochlear Ltd., Lane Cove, Sydney, NSW, Australia

2009

nach oben zur Jahresübersicht

Pasluosta C, Tims H, Chiu A W L
Nonlinear Control of Prosthetic Device using Slippage Sensor Feedback
2009 Southern Biomedical Engineering Conference
Pasluosta C, Tims H, Chiu A W L
Low Cost Control System for a Multifunction Prosthetic Hand: Prototype and Slip Detection Experiments
2009 26th Annual Houston Conference on Biomedical Engineering Research

1998

nach oben zur Jahresübersicht

Stieglitz T, Meyer J
Funktioneller Kontakt von Zellen und Biomaterialien
1998 2. Kongress der Deutschen Gesellschaft für Wundbehandlungen e. V. Sitzung: Stand, Anforderungen und Zukunftsperspektiven, Ulm
Stieglitz T
Flexible, Micromachined Systems for Interfacing Neurons
1998 2nd International Workshop on NEUROTRONICS, Wadern-Dagstuhl, Germany

1997

nach oben zur Jahresübersicht

Meyer J, Beutel H, Stieglitz T, Navarro X, Giesler T, Ruf H, et al.
Interfacing Neural Tissue and other Biological Cells Using Micromachined Devices
1997 Euro-BME Course: Interaction between Microtechnologies and Biomedical Structures, Aachen, Germany

1993

nach oben zur Jahresübersicht

Nützel A, Oettinger R, Stieglitz T, Vossius G
Entwurf von Fuzzy-Reglern und Neuronalen Netzwerken für zeitvariante Totzeitsysteme bei der Funktionellen Elektrostimulation
1993 Regelungstechnisches Kolloquium, Boppard

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2018

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Rickert J, Schuettler M, Stolle C, Wenzel F, Grigat N, Kohler F, Obert M, Rieger S, Stieglitz T, Ball T
Brain interchange: A novel brain computer interface system.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungTreatments of neurological disorders utilizing active implantable devices which interact with the activity of the brain are demonstrating increasingly promising advances. Next to the continuous improvement of established therapies for movement disorders, Epilepsy and chronic pain, new therapies for depression, paralysis and many more are under investigation. The current technology available for the development of these treatments is derived from the first active implants, the cardiac pacemakers, developed in mid to late 20th century: battery powered devices with few channels and limited intelligence. The Brain Interchange technology, developed in a joint effort by the University of Freiburg and CorTec, is a new system, enabling battery-free, intelligent closed-loop applications with up to 32 channels in its first version. The implantable part, including a novel hermetic encapsulation, custom electronics and firmware, were presented last year. The electrode technology will be presented in a companion poster. Here we present the progress in the development of the external parts and the software of the system and discuss potential applications. The first version of the external parts of the system manages power and communication with the implant, as well as the software for controlling the system. Physically, these parts consist of a head piece, a relay- and a controller unit. The main functions, accessible via a graphical user interface, are: managing recording and stimulation, measuring impedance and reading out humidity, temperature, supply voltage and unique ID of the implant. A filter pipeline for signal processing and feature extraction, suitable for computationally demanding closed-loop algorithms, and the control of external devices with minimal latency has also been implemented. For future collaboration partners programmable interfaces for C++, Matlab and Python are available. The development has been done under ISO-13485 and according to EN 62304. Potential applications range from closed-loop stimulation for the treatment of Parkinson’s disease or Epilepsy to the control of assistive technology in chronic paralysis or for rehabilitation purposes. Further applications could lie in closed-loop treatments in the peripheral nervous system.
Johnston M, Boehm T, Joseph K, Asplund M, Hofman U G, Thiele S, Haas C A,
Semi-automated quantification of the CNS immune response at the probe-tissue-interface.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungThe design of microelectrodes for electrical stimulation or recording of neuronal activity increasingly focuses on biocompatibility. Still, implantation of a cortical probe evokes a sustained sterile inflammatory response (SIR) within brain tissue. This manifests in activation of microglia, astrocytic scarring, neurodegeneration, and other molecular and morphological changes that may ultimately lead to failure of the device. To visualize the extent of the spatially limited tissue response, immunohistochemistry (IHC) is the well-established method of choice. But while qualitative assessment of resulting microscopic images can be easily accomplished, quantitative analysis poses a larger challenge to the investigator. This is partly due to the large number of images required to adequately represent the SIR, but also accounted for by high variability within and across tissue sections and animals. To this point there have been several publications that employed custom-built codes for quantification of IHC signals at the implantation sites of cortical electrodes. However, these differ greatly with respect to their evaluation methods and are not provided for open access. Hence, it is difficult to compare the extent of the SIR across different or even identical electrode types utilized by different groups. We therefore aimed at creating a semi-automated quantification method that allows fast and flexible delineation of the signal-intensity distribution from the site of lesion towards healthy brain tissue, based on the widely used software tools ImageJ and MATLAB. In this study cortical implantation of lithographically fabricated, flexible polyimide probes (10µm thickness with iridium oxide electrodes) was performed on adult Sprague Dawley rats. After different survival times transversal tissue sections were immunohistochemically stained and imaged with an epifluorescence microscope. Subsequent signal quantification was performed in concentric distance bins with flexibly adaptable size (the shape of the latter is determined by the respective cavity shape of the individual image). Processing artifacts can optionally be selected and excluded from the analysis. Apart from that normalization parameters can be modified towards the needs of the study design. This also yields the possibility of using differently processed and/or imaged tissue sections within one experimental population. Our approach provides a novel, straightforward tool for quantification of IHC-images that is versatile and adaptable for various purposes.
Johnston M, Boehm T, Joseph K, Asplund M, Hofman U G, Thiele S, Haas C A
Semi-automated quantification of the CNS immune response at the probe-tissue-interface.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungThe design of microelectrodes for electrical stimulation or recording of neuronal activity increasingly focuses on biocompatibility. Still, implantation of a cortical probe evokes a sustained sterile inflammatory response (SIR) within brain tissue. This manifests in activation of microglia, astrocytic scarring, neurodegeneration, and other molecular and morphological changes that may ultimately lead to failure of the device. To visualize the extent of the spatially limited tissue response, immunohistochemistry (IHC) is the well-established method of choice. But while qualitative assessment of resulting microscopic images can be easily accomplished, quantitative analysis poses a larger challenge to the investigator. This is partly due to the large number of images required to adequately represent the SIR, but also accounted for by high variability within and across tissue sections and animals. To this point there have been several publications that employed custom-built codes for quantification of IHC signals at the implantation sites of cortical electrodes. However, these differ greatly with respect to their evaluation methods and are not provided for open access. Hence, it is difficult to compare the extent of the SIR across different or even identical electrode types utilized by different groups. We therefore aimed at creating a semi-automated quantification method that allows fast and flexible delineation of the signal-intensity distribution from the site of lesion towards healthy brain tissue, based on the widely used software tools ImageJ and MATLAB. In this study cortical implantation of lithographically fabricated, flexible polyimide probes (10µm thickness with iridium oxide electrodes) was performed on adult Sprague Dawley rats. After different survival times transversal tissue sections were immunohistochemically stained and imaged with an epifluorescence microscope. Subsequent signal quantification was performed in concentric distance bins with flexibly adaptable size (the shape of the latter is determined by the respective cavity shape of the individual image). Processing artifacts can optionally be selected and excluded from the analysis. Apart from that normalization parameters can be modified towards the needs of the study design. This also yields the possibility of using differently processed and/or imaged tissue sections within one experimental population. Our approach provides a novel, straightforward tool for quantification of IHC-images that is versatile and adaptable for various purposes.
Valle G, Mazzoni A, Iberite F, D'Anna E, Strauss I, Granata G, Controzzi M, Clemente F, Rognini G, Cipriani C, Stieglitz T, Petrini FM, Rossini PM, Micera S
Biomimetic intraneural sensory encoding enhances sensation naturalness, tactile sensitivity and manual dexterity in a bidirectional prosthesis.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungThe lack of sensory feedback during grasping is a very important limitation of current hand prostheses, which affects their everyday usability. In the last years several research groups have demonstrated that nerve stimulation by implantable peripheral nerve interfaces can be reliably used to restore sensory feedback to upper limb amputees. They have shown that direct neural stimulation of peripheral nerves can effectively provide tactile information to the amputees, controlling the sensation intensity by modulating either the amplitude or the frequency of the injected stimuli. However, efforts are still necessary to identify encoding strategies converting tactile information into neural stimulation patterns capable of eliciting percepts that are both felt as natural and effective for prosthesis control. In this study, we compared the naturalness and efficacy of a set of encoding strategies based on biomimetic (model-driven) frequency modulation, amplitude modulation, or combinations of both. Such strategies were used to deliver neural stimulation to a trans-radial amputee implanted with intraneural electrodes (TIMEs). Frequency modulation was based on a biomimetic model (TouchSim) able to reproduce nerve activation patterns of the multifaceted mechanics of the skin and mechano-transduction. It was perceived as more natural, while amplitude modulation enabled better performance in tasks requiring fine identification of the applied force. Notably, hybrid encoding strategies involving both amplitude and frequency modulation were able to convey at least as much information as the amplitude modulation (for the completion of tasks), and were perceived at least as natural as the frequency modulation. The hybrid strategies improved the gross manual dexterity of the subjects during functional tasks while maintaining high manual accuracy. They also improved the level of prosthesis embodiment and reduced abnormal body perceptions of the phantom limb (“telescoping”). Encoding strategies based on the combination of biomimetic frequency modulation and amplitude modulation are able to provide highly sensitive and natural percepts and should be preferred in bidirectional prosthesis use.
Stieglitz T, Vomero M, Joseph K, Johnston M, Ciarpella F, Kirsch M, Boehm T, Fagida L, Thiele S, Haas C A, Hofmann U G, Asplund M
How flexibility and probe size influence chronic reliability: A study on batch processed polyimide-based intracortical neural arrays.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungFor short and long term neural applications, it is desirable to reduce or ideally eliminate the foreign body response to the implanted devices. One way to do so is to minimize the size of the device and thus the bending stiffness of the implant affecting the soft brain tissue. Recent findings in the field of neural engineering have led to the development of ultra-thin and ultra-flexible intracortical electrode arrays, presumably “invisible” for the host tissue and unable to trigger a noticeable immune response in long-term applications. However, reduced probe size comes at the cost of fewer individual electrodes, more challenging handling and fabrication, as well as mechanical properties less suited for chronic in vivo experiments. It is therefore important to better understand which design parameters offer the best trade-off. In this study, we compare two kinds of polyimide-based electrode arrays which differ only in their width: one kind is only 30 µm wide while the other has a width of 100 µm. Both device types are 12 µm thick and display electrodes 20 µm in diameter, spaced so that they target each one of the six cortical layers. The devices were chronically implanted into the brain of adult rat models and different time points were selected for perfusion and subsequent evaluation and quantification of the differences in the elicited immune response of the brain (via immunohistochemistry). Some of the probes were also used for long term recording of electrophysiological activity. Control devices (i.e. identical but without connector) were used to study the influence of the connector and cement on the short and long term tissue reaction to the implants. The wider probes (100 µm width) featured a pair of identical electrodes per cortical layer (instead of a single one) with the aim to achieve a better reconstruction of the neuronal configuration and status around the probe. The study’s goal is to systematically investigate the influence of selected geometrical parameters on the performance of thin-film polyimide based neural prostheses in vivo. Key concept: This study is part of a bigger project which aims to find a clear answer to the question “how small does a neural probe have to be to become invisible for the host tissue and yet to record long term high quality signals?”
Badi M, Wurth S, Kaeser M, Cvancara P, Stieglitz T, Courtine G, Capogrosso M, Bloch J, Rouiller E, Micera S
Neuroanatomical, computational, and experimental evidences for the use of intraneural peripheral nerve stimulation to induce fine hand movements.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungCervical spinal cord injury (SCI) and stroke severely impact grasping movements required for activities of daily living. Intraneural peripheral nerve stimulation enables specific activation of passing fibers. This paradigm has restored precise leg movements in animal models of SCI and selective sensation in human amputees. Intraneural peripheral nerve stimulation may also restore fine grasping in paralyzed hands, but this possibility has not been investigated. Here, we assess the feasibility of using intrafascicular electrical stimulation of peripheral nerves to produce precise hand movements in the non-human primate (NHP). We first extensively characterized the branching points of the median, radial, and ulnar nerves to their target muscles in the adult macaca fascicularis in order to identify the optimal implantation site for intraneural electrodes. We then reconstructed the tridimensional structure of the identified portion of each nerve in order to analyze the fascicular organization within the nerve at this level. Additionally, we assessed the distribution of motor fibers within the fascicles using immunohistochemistry. The obtained data was used to build realistic computational models of intraneural peripheral nerve stimulation for each nerve. The simulations confirmed the advantages of using intrafascicular electrodes to induce precise hand movements, demonstrating the possibility to selectively recruit patches of motor fibers without a priori knowledge of the electrode placement. We validated these results during electrophysiology experiments using transverse intrafascicular multichannel electrodes (TIMEs) implanted in the nerves of anesthetized NHPs. The stimulation achieved a selective recruitment of wrist and finger flexors and extensors in a reproducible manner across animals. We exploited these results to determine stimulation sequences that aimed at reproducing the muscle activation patterns underlying different grasping movements. For this, we mapped the obtained muscle recruitment maps to continuous EMG recordings during behavioral experiments and automatically optimized the selection of stimulation channels for each phase of the movement such as to reproduce the desired EMG pattern. Taken together, these results suggest encouraging evidences for the usability of the TIMEs to restore fine hand control after paralysis.
Gkogkidis CA, Bentler C, Wang X, Scheiwe C, Cristina Schmitz H, Stieglitz T, Ball T
Neurophysiological recording and stimulation using an off-the-shelf component wireless brain implant.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungBrain implants are increasingly used in neuroscientific research and medical applications. The requirements for such implants are diverse due to different experimental paradigms, scientific problem to address and demands by the researcher or clinician. To overcome these requirements, brain implants that can be built in a customized fashion might be beneficial. We previously introduced such a research grade wireless brain implant, developed exclusively using off-the-shelf components, which allows for quick and customized assembly. To verify the operability of the device during recording and stimulation, we present neurophysiological data obtained in an ovine animal model. During general anesthesia, the 63-channel µECoG electrode array was placed on the cortex of the sheep brain and both auditory and electrical stimuli were used to evoke neurophysiological responses which were recorded at a sampling rate of 4 kHz. Experiments performed in this study were conducted according to EU Directive 2010/63/EU and approved by the Animal Committee of the University of Freiburg and the Regierungspraesidium Freiburg, Germany. We show that our off-the-shelf research grade brain implant is capable to reliably record neurophysiological brain activity and electrically stimulate, evoking cortico-cortical responses, under in vivo conditions. The obtained neurophysiological activity showed clear responses with distinct spatio-temporal patterns to both auditory stimuli and cortical electrical stimulation, the latter with response patterns systematically depending on the exact stimulation site. In addition, spectral analysis revealed a neurophysiological frequency profile of the recorded activity which is in agreement with the well-known frequency power-law, i.e., the frequency-dependent linear decrease of log-log absolute spectral power. The presented neurophysiological data are in agreement with previously published recording and stimulation results obtained in sheep using different implantable devices that were not off-the-shelf. The results and their neurobiological implications as presented here highlight that off-the-shelf component brain interfacing devices are feasible and thus open up new avenues for implant-based research, especially when flexible requirements have to be addressed, as it is often the case in basic neuroscientific research. In the future we want to expand our approach to higher channel counts (128-channel high-resolution µECoG electrode arrays), higher recording sampling rate, and functional systems beyond the auditory system, as further use cases of our implant concept in neurotechnological research.
Petrini FM, Valle G, Bumbasirevic M, Barberi F, Guiraud D, Stieglitz T, Micera S, Raspopovic S
Sciatic intraneural stimulation evokes selective sensations from the phantom leg of trans-femoral amputees.
2018 Society for Neuroscience Meeting 3.-7.11.2018, San Diego, CA, USA SfN
KurzfassungLeg amputation destroys the communication between brain and environment during walking. Leg amputees rely on practically inexistent and often uncomfortable haptic feedback from the stump-socket interaction to monitor ground and obstacles contact, climb stairs, or walk in challenging environments. The lack of sensory feedback causes specific impairments to subjects that do not perceive the prosthesis as part of their body and risk falls, have decreased mobility, increased cognitive burden during walking resulting in prosthesis abandonment. In hand amputees, to restore the bidirectional communication, nerve interfaces have directly linked sensors readout from robotic hands to direct stimulation of nerves above injury. We believe that this strategy could also restore sensations from missing legs, with many scientific and technological barriers to overcome. It has never been proved that the electrical stimulation of the leg nerves by implantable neural interfaces can induce reliable sensations from missing leg and foot. In this work we developed a leg prosthesis restoring sensory feedback by means of direct nerve stimulation injected through transversal intraneural electrodes (TIME) implanted in the sciatic nerve. The stimulation was driven by the readout of pressure sensors placed under the prosthetic foot, and an encoder embedded in the prosthetic knee. We assessed the capability of 3 transfemoral amputees to recognize, blindfolded and acoustically insulated, the location where the prosthetic foot was touched and the degree of flexion of the prosthetic knee. The subjects were asked to recognize only touch, only flexion and then both conditions at the same time. We compared the performance when sensory feedback was restored and when no nerve stimulation was delivered. We found that single and double condition-tasks were executed on average respectively with a success rate of about 85% and 75%, when sensory feedback was provided. Without nerve stimulation the average success rate dropped to 25%.
Alt MT, Mittnacht A, Stieglitz T
Implantable Glass Waveguides and Coating Materials for Chronic Optical Medical Applications.
2018 40th International Conference of the IEEE Engineering in Medicine and Biology Society, 17.-21.07.2018, Oahu, Hawaii, USA IEEE, Seiten: 4595 - 4598
KurzfassungAn innovative fabrication process of glass waveguides on silicon substrates for miniaturized implants is presented. Thin glass was bonded on oxidized silicon wafers and patterned using wet etching. Multimode waveguides with different shapes and a low surface roughness as well as low scattering of light were successfully fabricated. For efficient coupling of light and accurate alignment, KOH-grooves were etched in the silicon with respect to the glass waveguides to attach optical fibers from external light sources. Towards higher biostability, several coating and cladding materials were evaluated in accelerated in vitro tests in 60°C PBS. TiO2, SiC polyimide, Parylene C and SU-8 showed a very stable optical transmittance after 320 days in accelerated aging while PECVD Si3N4 showed significant changes within the first days.
Kahn S, Scholz D, Ordonez JS, Stieglitz T
PDMS Gasket Underfill for Long-Term Insulation of High Density Interconnects in Active Implantable Medical Devices
2018 40th International Conference of the IEEE Engineering in Medicine and Biology Society, 17.-21.07.2018, Oahu, Hawaii, USA , Seiten: 2941 - 2944
KurzfassungThis work presents reliability investigations of silicone gasket as solid underfill for interconnection interfaces in hybrid implant systems with high channel count flexible electrode arrays and hermetically packed electronics. The gasket is fabricated by laser structuring thin sheet of silicone rubber. The surface activation of silicone sheet ensures mechanical bonds with the mating surfaces thereby improving the mechanical stability of the assembly and the insulation of the interconnects. The gasket samples with 10 × 10 openings for interconnect pads, each with diameter of 270 μm and a center to center pitch size of 490 μm, were sandwiched between a polyimide array and a metallized ceramic substrate. The gasket maintained high insulation impedance of 15 ± 0.30 MΩ between the adjacent interconnects with markedly capacitive behavior (phase angle, -89 °) after 17 weeks in soaked conditions under accelerated aging at 60 °C. The gasket also survived electrical stresses and sustained high impedance (10.93 MΩ with phase angle of -88 °) when subjected to constant 3 VDC for 100 days.
Erhardt JB, Martinez JA, Cork TE, Gessner I, Mathur S, Stieglitz T, Ennis DB
Assessment of Iron Oxide Nanoparticle Concentration for Distinct Intercranial EEG Electrode Localization in MRI.
2018 Proceedings of the 26th scientific meeting, International Society for Magnetic Resonance in Medicine, Paris, France , Seiten: 4057 - 4057
KurzfassungIntercranial EEG (icEEG) electrodes are implanted for pre-surgical assessment of cortical electrical activity in patients with epilepsy. MRI helps to localize the implant with respect to the individual’s anatomy and fMRI can improve understanding of the neuropathology. However, the magnetic susceptibility artifacts caused by the metal components of commercially available implants produce MRI artifacts that compromise the results especially in the direct vicinity of the implants. Next generation “thin-film” implants which feature 100x less metal thickness can mitigate these artifacts, but thin-film implants produce inconspicuous MRI signal voids in many clinical MRI sequences. Imperatively, physicians need to know the implant position and the value of EEG increases with the precision of electrode localization. Therefore, we investigated various concentrations of super paramagnetic iron oxide (SPIO) nanoparticles (NP) to label thin-film implants for localization in MRI using a range of sequences. In particular, we aim to create a marker that conspicuously renders the implant, enables spatial localization of the individual electrodes, and keeps disruptive imaging artifacts small.
Stieglitz T, Cvancara P, Mueller M, Eickenscheidt M, Liljemalm R, Fiedler E, Kahn S
Implantable microelectrodes - opportunites and challenges with respect to selectivity, stability and reliabilty.
2018 World Congress on Medical Physics and Biomedical Engineering (IUPESM 2018), June 3-8, 2018, Prague, Tschechien
KurzfassungMiniaturized electrode arrays for electrical stimulation in neural implants have to be stable, functional and reliable over the life-time of the implant, which is at best at least as long as the life time of the recipient. While cardiac pacemaker and cochlear implant electrodes stay stable for long time due to well established materials and precision mechanics manufacturing, more complex implants with higher channel count and integration density requires different technologies as well as materials. It is not only the dimension of thin-film metals that is more demanding than the one of solid electrode sheets in cochlear implants, cardiac, spinal cord and brain pacemakers but also the fact that surface effects predominate and promote corrosion mechanisms that are hardly seen in the established applications. In addition, adhesion of metals and polymer insulation is of utmost importance for device longevity and reliability. How can these challenges be combined with the target specifications for high spatial selectivity and the possibility of current steering when using multipolar stimulation paradigms ? This presentation combines material sciences foundations with requirements of electrical stimulation in movement rehabilitation to discuss opportunites and challenges in development of miniaturized electrode arrays. Examples include delivery of sensory feedback via stimulation of afferent fibers in the peripheral nervous system and recording of neural signals from the central nervous system as input parameter in brain-computer-interface applications to control movement of either artificial or paralyzed limbs. Results from preclinical as well as from human clinical trials are presented to discuss material-tissue interactions and microsystem stability in chronic implantation scenarios and the influence of these findings to spatial selectivity that is needed for sophisticated movement rehabilitation by functional electrical stimulation.
Vomero M, Porto Cruz MF, Zucchini E, Shabanian A, Delfino E, Carli S, Fadiga L, Ricci D, Stieglitz T
Achieving Ultra-Conformability with Polyimide-Based ECoG Arrays.
2018 Engineering in Medicine and Biology Conference (EMBC) 2018. 17-21 July 2018 . Honolulu, Hawaii, United States IEEE, Seiten: 4464 - 4467
KurzfassungMicro-electrode arrays for electrocorticography (ECoG) represent the best compromise between invasiveness and signal quality, as they are surface devices that still allow high sensitivity recordings. In this work, an assessment of different technical aspects determining the ultimate performance of ultra-conformable polyimide-based μECoG arrays is conducted via a finite element model, impedance spectroscopy measurements and recordings of sensorimotor evoked potentials (SEPs) in rats. The finite element model proves that conformability of thin-film arrays can be achieved with polyimide, a non-stretchable material, by adjusting its thickness according to the curvature of the targeted anatomical area. From the electrochemical characterization of the devices, intrinsic thermal noise of platinum and gold electrodes is estimated to be 3–5 μV. Results show that electrode size and in vitro impedance do not influence the amplitude of the recorded SEPs. However, the use of a reference on-skull (a metal screw), as compared to reference on-array (a metal electrode surrounding the recording area), provides higher-amplitude SEPs. Additionally, the incorporation of a grounded metal shield in the thin-film devices limits crosstalk between tracks and does not compromise the recording capabilities of the arrays.
Pfau J, Leal Ordonez JA, Stieglitz T
In Situ Measurement of Stimulus Induced pH Changes Using Thin- Film Embedded IrOx pH Electrodes.
2018 EMBC 2018 „40th International Engineering in Medicine and Biology Conference of the IEEE Engin. in Medicine and Biology Society“ , 17.07.-21.07.18 in USA Hawaii, USA IEEE, Seiten: 5049 - 5052
KurzfassungThe high complexity of the biological response to implanted materials builds a serious barrier against implanted recording and stimulation electrode arrays to succeed in clini- cally relevant chronic studies. Some of the cell and molecular inte ractions and the ir contribution to inflammation and de vice failure are s till uncle ar. The inte rre late d me chanis ms le ading to tissue damage and electrode array failure during simultaneous faradaic, electrochemical reactions and biological response under electrical stimulation are not understood sufficiently. One variable, with which inflammatory and electrode surface processes can be analyzed and assessed, is the pH change in the immediate environment of the material-tissue interface. Here, the greatest challenges are in the biocompatibility and in-vivo long-term stability of selected sensor materials, the measure- ment of small transient pH oscillations and positioning of the sensor at a defined and nearest possible distance in the mi- crometer range, to the site of activity without the pH sensing being affected by the material-tissue interactions itself. This work represents the in-situ measurement of local and transient pH changes at a pulsed electrode with an embedded in-vivo compatible pH sensor and therein differentiating from current approaches of pH sensing during electrical stimulation.
Langenmair M, Martens J, Gierthmuehlen M, Plachta DTT, Stieglitz T
Low temperature approach for high density electrical feedthroughs for neural implants using maskless fabrication techniques.
2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 18.- 21.07.2018, Oahu, Hawaii, USA IEEE, Seiten: 2933 - 2936
KurzfassungImplantable electronic packages for neural implants utilize reliable electrical feedthroughs that connect the inside of a sealed capsule to the components that are exposed to the surrounding body tissue. With the ongoing miniaturization of implants requiring ever higher integration densities of such feedthroughs new technologies have to be investigated. The presented work investigates the sealing of vertical feedthroughs in aluminum-oxide-substrates with gold stud-bumps. The technology enables integration densities of up to 1600/cm 2 while delivering suitable water leak rates for realistic implantation durations of miniaturized packages (feedthrough-count $>50$, package-volume $<2$ cm $^{3})$ of more than 50 years. All manufacturing steps require temperatures below $420 ^{\circ}\mathrm {C}$ and are suitable for maskless rapid prototyping.
Rehberger F, Eickenscheidt M, Stieglitz T
Micro-folded 3D neural electrodes fully integrated in polyimide.
2018 Engineering in Medicine and Biology Conference (EMBC) 2018. 17-21 July 2018 . Honolulu, Hawaii, United States IEEE, Seiten: 4587 - 4590
KurzfassungRecent neural interfaces are characterized by high functionality and good adaptation to the target tissue. Still, the underlying manufacturing process is mainly planar and so are the device and contact surface. Therefore, three-dimensional structures to contact neuronal tissue are desired to gain higher selectivity. In the present study, local bending structures integrated in flexible electrode arrays based on polyimide are investigated. The bending is achieved by the contraction of a second polyimide (Durimide) that is embedded into grooves with a width of a few micrometers. The angle of the bending can be controlled with a high accuracy from 3 to 20 degrees by changing the geometry of the grooves and the imidization temperature These bending structures can be combined to achieve any desired angle for specific applications.
Gkogkidis CA, Bentler C, Wang X, Gierthmuehlen M, Scheiwe C, Schmitz HC, Haberstroh J, Stieglitz T Ball T
Neurophysiological Evaluation of a Customizable μECoG-based Wireless Brain Implant.
2018 2018 40th AnInternational Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) , 18.-21.07.2018, Oahu, HI, USA IEEE, Seiten: 2953 - 2956
KurzfassungThe number of implantable bidirectional neural interfaces available for neuroscientific research applications is still limited, despite the rapidly increasing number of customized components. We previously reported on how to translate available components into ”ready-to-use” wireless implantable systems utilizing components off-the-shelf (COTS). The aim of the present study was to verify the viability of a micro-electrocorticographic (μECoG) device built by this approach. Functionality for both neural recording and stimulation was evaluated in an ovine animal model using acoustic stimuli and cortical electrical stimulation, respectively. We show that auditory evoked responses were reliably recorded in both time and frequency domain and present data that demonstrates the cortical electrical stimulation functionality. The successful recording of neuronal activity suggests that the device can compete with existing implantable systems as a neurotechnological research tool.
Boehler C, Asplund M
PEDOT as a high charge injection material for low-frequency stimulation.
2018 40th International Conference of the IEEE Engineering in Medicine and Biology Society, 17.-21.07.2018, Oahu, Hawaii, USA IEEE
KurzfassungAlternating current stimulation (ACS) provides a versatile tool for modulating brain activity and presents a promising strategy for the treatment of neurological disorders like Parkinson’s disease or epilepsy. Stimulation of neural tissue at low-frequency however poses new challenges on conventional electrode materials which support limited charge transfer in the desired frequency range, from less than 0.1 Hz to several tens of Hz. In our study we address this challenge by investigating the charge transfer properties of PEDOT/PSS coatings for low-frequency applications, focusing on the impact of the polymer bulk. PEDOT films of various thicknesses were exposed to low-frequency as well as DC stimulation in vitro and compared to Pt and IrOx electrodes as controls. The charge injection performance of the metallic substrates could be substantially improved already by a thin PEDOT coating. Additionally a linear dependency between charge injection and polymer thickness suggests that PEDOT coatings are promising as materials for future ACS applications.

2017

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Raspopovic S, Petrini FM, Valle G, Cvancara P, Hiarrassary A, Guiraud D, Alexandersson A, Stieglitz T, Micera S, Bumbasirevic M
Bionic legs restore the dexterity, confidence and ownership in lower-limb amputees.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15. 2017,
KurzfassungThe lack of natural sensory feedback causes specific impairments to amputee patients: they do not perceive the prosthesis as a part of their body (low embodiment) and risk falls (low dexterity), hence do not rely on it and execute counterbalancing movements which increase fatigue. It also results in up to 60% of prosthesis abandonments (low confidence). Some efforts to restore sensory feedback in lower limb amputees have been conducted with non-invasive technologies, without success in solving these issues. In this work we developed the first prosthetic leg, which restores sensory feedback to amputees by means of implanted intraneural electrodes, in order to enable patients full recovery of dexterity, confidence and embodiment boosting. Two transfemoral amputees underwent the implant of 4 intraneural electrodes in the proximal section of tibial nerve for more than 100 days each. We showed that natural sensations of touch, pressure, vibration and muscle contractions could be elicited on the phantom leg, on the numerous positions over the foot sole and lower leg. Then these sensations were used within the bidirectional prosthetic control. A commercial prosthetic leg with an encoder embedded in the knee was equipped with a custom made sensorized sole, recording the pressure information from 7 positions of the foot sole. The readout of these sensors and encoder was used to drive wirelessly the stimulation of 5 active sites, eliciting natural touch under the foot sole and calf contraction, intuitively interpreted by the subject as knee flexion. The subjects then underwent a set of investigations, devoted to explore singular hypotheses: i) walking over obstacles, without possibility to visually inspect (confidence test), ii) walking over the stairs, sand, gravel and straight lines (dexterity and mobility test) and iii) induced ownership (embodiment tests). Remarkably, the proposed intervention showed significantly increased confidence, higher dexterity and mobility, together with the clear embodiment augmentation. Natural sensory feedback from missing leg can be elicited to the transfemoral amputees, and integrated into the successful natural control and holds the promise to overcame the limitations of the present prosthetic devices.
D´Anna E, Valle G, Strauss I, Patton J, Petrini FM, Raspopovic S, Granata G, Di Iorio T, Stieglitz T, Rossini PM, Micera S
Simultaneous tactile and proprioceptive feedback in myo-controlled hand prostheses using intraneural electrical stimulation.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15. 2017,
KurzfassungThe hand is a versatile sensorimotor system, capable of performing a wide range of actions, as well as providing rich afferent information about the environment. Consequently, hand amputation leads to severe disability. Current prosthetic replacements offer partial relief, but are limited by the low amounts of sensory feedback delivered to the user. Instead, wearers often need to rely on visual cues to perform tasks, leading to frustration and prosthesis abandonment. Recently, several groups have demonstrated the possibility of restoring tactile feedback in upper limb prostheses by stimulating peripheral nerves with implantable electrodes. Although the addition of artificial touch has lead to functional benefits in prosthesis use, there is great interest in restoring more complete afferent information, including other modalities. Specifically, proprioception is an important part of the afferent stream of information flowing from the periphery to the central nervous system, and plays a major role in the generation of smooth and precise motor control. To date, proprioception has been particularly challenging to restore in a homologous and somatotopical way using both invasive and non-invasive approaches. In this study, we demonstrate that by exploiting an intraneural interface to perform sensory re-mapping, it is possible to deliver proprioceptive feedback in real-time and in parallel with tactile information. We performed several functional tests, during which a trans-radial amputee showed high, close-to-natural propioceptive acuity, with a measured median joint angle reproduction accuracy of 8.6° and a median threshold to detection of passive movement of 12.5°. Furthermore, the subject was able to use both tactile and proprioceptive feedbacks to recognize objects of different sizes and compliances with a very high level of accuracy (87.5%). Finally, we compared the performance of the proposed sensory re-mapping approach with non-invasive alternatives. Overall, the re-mapped proprioceptive acuity was comparable to the acuity observed in healthy subjects, and conferred the ability to perform meaningful functional tasks. This study provides a proof-of-concept that proprioception can be restored using sensory re-mapping with an invasive neural interface. As such, it represents a promising first step in the direction of multimodal sensory neuroprostheses.
Valle G, Strauss I, Petrini FM, Granata G, Di Iorio R, Cvancara P, Mueller M, Barbaro M, Raffo L, Stieglitz T, Paspopovic S, Rossini PM, Micera S
A comparison between encoding strategies for restoring sensory feedback in a bidirectional hand prosthesis.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15. 2017,
KurzfassungIn the last years several research groups have demonstrated that nerve stimulation by implantable peripheral nerve interfaces can be reliably used to restore sensory feedback to upper limb amputees. It has been shown that this improves the performance of controlling hand prostheses. Different strategies to transduce the readout of hand prostheses sensors have been tested. Recently, it has been demonstrated that the charge and frequency of neural stimulation have a linear relationship with the intensity of the elicited sensation. Here, we developed a bidirectional hand prosthesis, in which the readout of force sensors in the hand is linearly related or to the charge or to the frequency of intraneural stimulation. This was done in order to verify whether one approach produced better than the other in improving motor control performance. We implanted the median and ulnar nerve of a transradial amputee, above the elbow, with 4 TIME electrodes. We identified the active sites able to elicit the sensation of touch/pressure in the median and ulnar areas of the hand. The subject controlled the hand prosthesis using the residual arm muscles, whose activation was recorded by surface EMG electrodes. The acquired signals were pre-processed and fed to a KNN to classify, within 100 ms delay, the intention to open, close and not move the hand. The subject blind-folded and acoustically isolated was engaged in 4 tasks from the literature: force control, object location, compliance and shape recognition. In the first one, the subject was asked to control the force level he could exert by the prosthesis on a pressure sensor. 3 levels of force were required either in a casual order or in a ramp fashion from the minimum to the maximum one and back. In object location the subject had to recognize if an object was placed in the ulnar or median portion of the hand or in both. Finally, the volunteer had to distinguish among 3 objects of different compliance or shape. The subject successfully performed object location, compliance and shape recognition, with both charge and frequency modulation. During the force control task, instead, while the volunteer was perfectly capable of controlling three randomly required force levels with both stimulation strategies, she managed to execute the ramp only by means of charge modulation. When the frequency was modulated, indeed, it was impossible for the subject to control the force level from the maximum to the minimum one. This suggests that the intensity of sensations elicited by neural stimulation decays rapidly over time when high frequency is used, making charge modulation strategy a more reliable to exploit in bidirectional prostheses development.
Rickert J, Kohler F, Stolle C, Stieglitz T, Fischer J, Schuettler M, Gkogkidis A, Wang X, Gierthmuehlen M, Scheiwe C, Ball T
An implantable brain-computer interface for investigation of closed-loop therapies.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15. 2017,
KurzfassungIn 1997, deep brain stimulation (DBS) was approved by the FDA for treatment of essential tremor. In the following decades neuromodulation of the CNS became a active field and was applied for treating different conditions. Similar to the technological progress of cardiac pacemakers, concepts were developed to adapt the stimulation to the patient's need, making the devices responsive. Today, two of these closed-loop devices are approved for clinical use, Medtronic Activa PC+S and Neuropace RNS. Both devices work with eight electrode contacts on the surface or deep inside the brain and permit delivery of electrical stimuli initiated, or modified in intensity, based on neural recordings. Here, we present a closed-loop device that overcomes current application limitation by increasing the electrode contact number, minimizing the closed-loop response time and transferring the closed-loop algorithms to a device outside the body, allowing maximum freedom for clinical research. The design is inspired by today's cochlear implants: The implant is wirelessly powered by a body-external transceiver. Cortical electrode arrays and DBS electrodes can be connected to the hermetically packaged implanted electronics. The device records synchronously from 32 electrode contacts at 1kS/s (16bit) at a pass band of 0.5 to 450Hz. Data are wirelessly streamed to the body-external transceiver, which is connected to a laptop-PC, running the control software. The software can send instructions to the implant to generate electrical stimuli of up to 6mA on each of the 32 electrode contacts. Typically, it takes some 10ms for closing the loop of recording and recording-based stimulation, strongly depended on the signal analysis and decision-taking algorithms used. The system was implanted in sheep (approved by the Regierungspraesidium Freiburg, Germany and the Animal Ethics Committee of the University of Freiburg) to investigate long-term functionality and biological acceptance. Excellent robustness of the implanted hardware, good biological acceptance and stable recording signal quality could be demonstrated. We present the latest results from the animal studies and technical improvements developed based on prior results. In conclusion, the implant system presented has the potential for researching closed-loop therapies for the central nervous system. The validations towards clearance for clinical studies are currently on the way.
Petrini FM, Valle G, Berberi F, Bortolotti D, Cvancara P, Hiarrassary A, Guiraud D, Divoux JL, Lesic A, Stieglitz T, Micera S, Raspopovic S, Bumbasirevic M
Sensory feedback driven by intraneural stimulation allows amputees to reduce energy consume during walking and decreases phantom limb pain.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15. 2017,
KurzfassungLeg amputees do not have natural sensory information from commercial prostheses. As a consequence, amputees risk falls, and lose confidence in the prosthesis, so that patients exert counterbalancing movements with the sound leg increasing metabolic costs, and leading to catastrophic events as heart failures. Also, because of the lack of sensory feedback, 50 to 80% of amputees report phantom pain from the missing leg. Some efforts to restore sensory feedback in lower limb amputees have been conducted with non-invasive technologies, but they failed in addressing these problems. In this work we developed the first prosthetic leg, which restores sensory feedback to amputees by means of implanted intraneural electrodes, in order to reduce metabolic costs during walking and to decrease phantom limb pain. Two transfemoral amputees underwent the implant of 4 TIME electrodes in the tibial nerve for three months. The response of the subjects to the nerve stimulation was characterized during the whole course of the study. We showed that natural sensations of touch and muscle contractions could be elicited on the phantom leg on the whole area of innervation of the tibial nerve. A commercial prosthetic leg with an encoder embedded in the knee was equipped with a custom made sensorized sole, giving pressure information from 7 positions of the foot sole. The readout of these sensors was used to drive wirelessly the stimulation of 4 active sites, eliciting natural touch under the foot sole and calf contraction, intuitively interpreted by the subject as knee flexion. The subjects were asked to walk with the prosthesis restoring sensory feedback at increasing velocity on a treadmill for 8 minutes. Then they were asked to walk outdoor for 6 minutes at a self-assessed speed on a fixed path on send and grass. These trials were repeated with and without restored sensory feedback, while the metabolic costs were measured. Finally, the subjects underwent sessions of 10-minutes continuous monopolar biphasic square stimulation. The volunteers replied to standard pain questionnaires before and after the stimulation. Remarkably, we measured significantly reduced metabolic costs both indoor and outdoor when the subjects walked with the prosthesis restoring sensory feedback. Furthermore, the subjects reported a significant decrease of phantom pain after the provision of 10 minutes stimulation. These results show that natural invasive sensory feedback restored by means of intraneural electrodes successfully addresses current limitations of prosthetic devices, opening the way for a dramatic improvement of amputees’ life.
Stieglitz T, Oliveira A, Ashouri D, Vomero M, Eickenscheidt M
Laser-induced carbon microelectrode arrays for chronic neural applications.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15, 2017
KurzfassungIn the field of neural prostheses, much attention has lately been given to the long-term performance not only of the electronic components but also of the parts directly interfacing with the nervous system. Neural interfaces have, in fact, a critical role in chronic applications, where they have to outlast the highly humid and oxidative body environment without undergoing delamination, corroding and without losing their functionality over time. Among all, carbon has been proved to be the material with the highest potential to contemporary serve as biomaterial for recording nerve cells activity, electrically stimulating them and, in addition, for selectively detecting the presence of neurotransmitters or other electrically active biomolecules. However, the feasibility of the fabrication method - with respect to process complexity and cost - is a factor of great importance and it is not always easy to accomplish with carbon electrodes. In this work, we present a new method to manufacture thin-film microelectrode arrays (MEAs) with laser-induced carbon active sites made from parylene c coatings on platinum iridium tracks. Such MEAs are manufactured without the need for cleanroom and MEMS processes. Prototypes of these carbon electrodes were evaluated first in vitro in hydrogen peroxide to mimic the post-surgery oxidative environment due to the acute inflammatory reaction to the implant. Electrodes were stimulated using biphasic pulses to prove their stability under electrical stress and testes with respect to their biosensing capabilities on different concentrations of dopamine in PBS. Results show that our laser-induced carbon electrodes do not deteriorate under chemical and electrochemical loads. They were able to detect different dopamine levels in vitro. These new laser-induced carbon electrodes show promising potential to successfully be implanted in vivo and be used for long-term neural applications for recording, stimulation and biochemical sensing.
Liljemalm R, Fries P, Lewis CM, Engel AK, Pieper F, Engler G, Fiedler E, Stieglitz T
Long-term stability of implanted high density polyimide ECoG arrays.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15. 2017,
KurzfassungThe technology for miniaturization of bioelectronics is making great progress, and the interest for high density electrode recordings in the neural systems is continually increasing. High density recording of, e.g., the cortical activity could help scientists to elucidate the language of the brain and further increase our understanding of the behavior of the cells in the neural system. Furthermore, a high density electrode implant would also increase the possibility to choose specific electrodes, e.g. in the proximity of the desired neural target, or active sites instead of silent. Also, the ability to map larger surface areas with high density arrays could help growing the understanding for the connectivity between different regions in the brain. In our group we have developed several structures based on the polymer polyimide, which is a flexible, stable and biocompatible polymer, therefore excellent for neural probes, especially for long-term applications with high demands on reliability. Designs have been targeted to animal models of turtles, rats, ferrets, cats and macaque monkeys. Modular, finger-based designs adapted well to the two-dimensionally curved structure of the brain surface even though the substrate material itself is not stretchable. Electrode size and pitch have been adapted to the size of the target structures. Array variations comprised 36, 64, 96, 192 and 252 electrode sites. Several high density ECoG arrays have been fabricated and implanted into primates. These showed good long-term stability and both single-unit activity, as well as multi-unit activity and local field potentials could be recorded via platinum and iridium oxide thin-film metal sites. Signal-to-noise ratios were sufficiently high over months and degraded only slowly. Results on stability and functionality are promising and consistent with other translational studies on peripheral nerves.
Pasluosta CF, Kiele P, Resch A, Stieglitz T
Restoring natural sensory feedback in amputees via electrical stimulation after targeted muscle reinnervation.
2017 the 47th annual meeting of the Society for Neuroscience (SfN 2017), Washington, D.C., USA, November 11-15. 2017,
KurzfassungThe loss of a limb permanently disrupts daily living activities. Prosthetic devices are an alternative to partially circumvent this disability. The lack of sensory feedback of current prosthetic options limits their acceptance and usability rate. In the upper limb, somatosensory percepts are essential for proper object manipulation, while in the lower counterparts proprioceptive and cutaneous sensations are required to maintain balance and stable gait. Restoral of sensory feedback also improves the sense of embodiment of prosthetic limbs, which positively impacts user satisfaction. The introduction of surgically targeted muscle reinnervation (TMR) led to promising outcomes in terms of controllability of prosthetic devices, and in providing a novel channel to restore sensory information. TMR consists on re-routing the remaining peripheral nerves from the amputee’s stump to the chest area. After transferring the nerves into the chest, afferent and efferent fibers reinnervate the hosting muscles, amplifying the signals from the efferent pathways, and providing a more selective channel for activating afferent fibers. We have previously demonstrated that electrical stimulation of peripheral nerves using implanted intrafascicular electrodes elicits natural sensory feedback during real-time, bidirectional control of a prosthetic hand. In this study, we propose that after TMR, the afferent reinnervated fibers can be electrically stimulated to restore natural somatosensations. We further propose that this stimulation can be provided wirelessly by capacitive coupling through the chest skin, eliminating the need for percutaneous cables and implanted electronics. An electrode implanted in the inner side of the skin picks up a portion of the current flowing inside bodily tissue when two surface electrodes located in the vicinity of the reinnervated muscles are electrically stimulated. Practically, this implanted electrode is electrically connected to the fibers reinnervated in the chest muscles such to transfer the collected current and depolarize the surrounding nerve axons. We simulate different stimulation paradigms of electrical currents travelling through the skin to the sensory fibers. Activation outputs of reinnervated afferent fibers of the peripheral nerves are then analyzed using a hybrid model of the electrical field generated by the stimulation. The outcomes of this proof-of-concept prototype as well as the implication of this novel technique for restoring natural sensory feedback in the amputee are discussed.
Bentler C, Stieglitz T
Building wireless implantable neural interfaces within weeks for neuroscientists.
2017 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC),11. - 15. July 2017 Jeju Island, Korea Conf Proc IEEE Eng Med Biol Soc, IEEE, Band: 2017, Seiten: 1078 - 1081
KurzfassungThe variety of "`ready-to-use'" implantable recording and stimulation systems commercially available for neuroscience is very limited and fabrication of custom made implants is commonly considered expensive and time consuming. We present a circuit design that allows cost efficient and fast translation of available components into fully wireless implants. As demonstration fully wireless implantable bidirectional neural interfaces are presented which are made of commercial off-the-shelf components (COTS) only. It is demonstrated that they are competitive to currently available state-of-the-art systems regarding size and performance.
Vomero M, Castagnola E, Ordonez JS, Carli S, Zucchini E, Maggiolini E, Gueli C, Goshi N, Fadiga L, Ricci D, Kassegne S, Stieglitz T
Improved long-term stability of thin-film glassy carbon electrodes through the use of silicon carbide and amorphous carbon.
2017 2017 8th International IEEE/EMBS Conference on Neural Engineering (NER) ,15 August 2017 , Shanghai, China IEEE
KurzfassungLong-term stability of neural interfaces is a challenge that has still to be overcome. In this study, we manufactured a highly stable multi-layer thin-film class of carbon-based devices for electrocorticography (ECoG) incorporating silicon carbide (SiC) and amorphous carbon (DLC) as adhesion promoters between glassy carbon (GC) electrodes and polyimide (PI) substrate and between PI and platinum (Pt) traces. We aged the thin-film electrodes in 30 mM H2O2 at 39 °C for one week - to mimic the effects of post-surgery inflammatory reaction - and subsequently stressed them with 2500 CV cycles. We additionally performed stability tests stimulating the electrodes with 15 million biphasic pulses. Finally, we implanted the electrodes for 6 weeks into rat models and optically characterized the explanted devices. Results show that the fabricated ECoG devices were able to withstand the in vitro and in vivo tests without significant change in impedance and morphology.
Pfau J, Stieglitz T, Ordonez JS
Mechanical Deformation and Chemical Degradation of Thin-Film Platinum under Aging and Electrical Stimulation.
2017 8 th International IEEE EMBS Conference on Neural Engineering, 25. - 28.05.2017, Shanghai, China The Institute of Electrical and Electronics Engineering, INC., Engineering in Medicine and Biology Society
KurzfassungMiniaturization of electrodes is a prerequisite of selective and targeted interaction with single neurons, enabling more applications in the continuously growing field of neuroprostheses. Miniaturization in all three dimensions of the electrical contact sites should maintain or increase longevity and electrical functionality. The thin-film metallization of the electrode site, which is only a couple of hundreds of nanometers thick, has to withstand high chemical load through the corrosive environment in the body and the electrochemical processes during electrical stimulation in vivo. Platinum (Pt), which is known to be chemically inert and mechanical stable as bulk material shows a lack of chemical and mechanical integrity applied in thin-film microelectrodes. In our study we investigated failure mechanisms of thin-film Pt electrodes under conditions of electrode aging and electrical stimulation in different physiological media. To understand and eventually overcome stability loss, we investigated the intrinsic structural stress and deformations that arose from mechanical loading through chemical impact and electrical stimulation using optical microscopy and white-light interferometry. Electrochemical measurements indicated oxidation and surface roughening as two of the degradation processes in thin-film electrodes. From the results presumptions about the underlying microstructural changes were made.
Erhardt JB, Vomero M, Leupold J, Gueli C, Kassegne S, Stieglitz T
Quasi MR-imaging Artefact Free ECoG and Intracortical Electrodes.
2017 International Society for Magnetic Resonance in Medicine, Honolulu, Hawaii, USA 22. - 27.04.2017
KurzfassungThe combination of implantable neural electrodes and fMRI holds great potential for better understanding the human brain. However, the image acquisition - especially in the vicinity of the implants - is compromised by artifacts caused by metal components. In this work we address this issue by studying different types of devices in terms of designs and materials, and by quantifying their MRI artifacts. Doing so we demonstrate the quasi artifact-free behavior of a hybrid probe combining surface and penetrating carbon electrodes into a single sheet of polyimide, after comparing it with conventional implants in high field MRI and clinical fMRI.
Bisoni L, Carboni C, Puddu R, Barabino G, Pani D, Raffo L, Mueller M, Stieglitz T, Del Valle J, de la Oliva N, Delgado-Martinez I, Navarro X, Barbaro M
A 64-channels neural interface for biopotentials recording and PNS stimulation.
2017 Conf Proc IEEE Eng Med Biol Soc, Band: 2017, Seiten: 1938 - 1941
KurzfassungA biomedical interface that combines into a single and compact device the recording of biopotentials and the electrical stimulation of neural fibres is presented. It is intended for enabling the control over a robotic hand and for restoring the sensory feedback in amputees by directly interfacing the peripheral nervous system (PNS) in closed-loop. A modular system consisting in one or more independent 16-channels bidirectional units was conceived. Each module is based on three 0.35μm bulk-CMOS integrated circuits (ICs): a recording unit, a High-Voltage (HV) stimulator and a HV booster. A tunable bandwidth (10Hz-8kHz) allows the recording IC to acquire both electroneurographyc (ENG) and electromiographyc (EMG) signals with a programmable gain up to 43.5dB. The signals are then converted into a digital domain by means of a ΣΔ converter. Due to the typical high impedance at the electrode-tissue interface, a programmable HV booster that increases the stimulation voltage up to 19V was designed. It is directly controlled by the stimulation module that generates current-based pulses with a programmable amplitude and pulse-width. The whole system was validated by means of in-vivo experiments in rats.
Langenmair M, Kimmig F, Boretius T, Plachte DTT, Stieglitz T
A new concept of interconnecting feedthrough-bearing substrates with conducting wires in active implantable medical devices
2017 Jahrestagung der BIOMEDIZINISCHEN TECHNIK und Dreiländertagung der MEDIZINISCHEN PHYSIK Dresden I 10.–13. September Biomed Eng-biomed Te, Band: 62, Ergänzungsband: 1, Seiten: S447 - S452
KurzfassungThe development and application of new active implantable medical devices (i.e. neuromodulators for the treatment of hypertension) require an ever-increasing amount of stimulation and recording sites. In many cases the therapeutic electrical signals generated by the implant penetrate a hermetic enclosure of the involved electronics via feedthrough structures. Typically, a multi-fibre-core cable connects these feedthroughs with the machine-tissue interface. In state-of-the-art applications (with a low amount of channels), i.e. pacemakers or cochlear implants, cables are connected directly to the metal pins or ribbons of the hermetic feedthroughs. This well established and reliable interconnecting technique, however, comes to its limitation when an active implant requires a high amount of channels. For an envisioned packaging concept new ways to connect thin metal wires to the feedthrough-bearing ceramic substrate are developed and characterized. The investigated method uses glass-based screenprinting paste with a gold-filler as a bondpad for metal wires. Sputtered metal connects the fired paste and the location of the feedthroughs on the ceramic substrate. Laser-welding is the method of choice for a long term stable mechanical and electrical connection between the wires and the paste. In this new approach, the paste is applied in laser structured trenches on the ceramic substrate. This allows for rapid prototyping of geometries, since no screen printing mask is needed to apply the paste before firing. Furthermore, the trenches are designed in a way, that the metal wire can be pressed in a cavity, which constrains the movement of the wire in all directions during the laser-welding of the wires. This can enhance the repeatability and speed of the welding process significantly. Since the interconnects between the wire and the paste are located beneath the ceramic surface, high resistance to slong term stability of this packaging concept.
Koch J, Schuettler M, Stieglitz T
Design of contact zone topography for implantable high-channel electrical connectors.
2017 Conf Proc IEEE Eng Med Biol Soc, Band: 2017, Seiten: 238 - 241
KurzfassungDetachable high-channel electrical connections pose a bottleneck on the path to active implants with higher numbers of electrode contacts and miniaturized geometries. Not only low-resistance, reproducible and reliable contacts have to be realized but also seals that ensure electrical insulation in the harsh body environment. Using planar contact arrangements one can resort to laser microprocessing leading to minimal size connectors. However, this poses the need to carefully design the topographies within the contact zone. In this study, we assess different methods to design the topography of planar contact pad arrays. Using topographical analysis and evaluation of electrical functionality, influential mechanisms were identified and two functional ones have been selected.
Kiele P, Cvancara P, Mueller M, Stieglitz T
Design of experiment evaluation of sputtered thin film platinum surface metallization on alumina substrate for implantable conductive structures.
2017 Conf Proc IEEE Eng Med Biol Soc, Band: 2017, Seiten: 1066 - 1069
KurzfassungReliability and reproducibility of implants and their fabrication are highly depending on the assembly and packaging procedures. Individual fabrication skills like soldering introduce inaccuracies and should be avoided as much as possible. Screen printing is often utilized for the metallization of ceramics. Using platinum/gold (Pt/Au) paste liquidus diffusion leads to a low adhesion strength of the Pt/Au pads after soldering. As an alternative, sputtering of thin film surface metallization was investigated. However, this alternative comes with a huge amount of different layer and parameter setups. In order to keep the amount of experiments and data acquisition in a reasonable magnitude, the Design of Experiment (DoE) evaluation displays a powerful tool. We found an optimal layer setup that maximizes the adhesion strength of the layer, while simultaneously minimizing the sheet resistance and removing the dependency of soldering time.
Khan S, Ordonez JS, Stieglitz T
Dual-Sided Process with Graded Interfaces for Adhering Underfill and Globtop Materials to Microelectrode Arrays
2017 The 8th International IEEE EMBS Conference on Neural Engineering, May 25-28, 2017, Shanghai, China
KurzfassungMaintaining the insulation between adjacent electrical interconnections is critical for the success of active implantable medical device. Underfilling and globtop coating of dense arrays of microfabricated interconnects pose a big reliability risk. Contamination, voids and the difficulty to deposit liquid underfillers with the appropriate adhesive behavior remains a major hurdle when developing miniaturized high-channel neural interfaces. We approach a bottom up process to fabricate adhesion promoting, graded interfaces on the bottom and top side of polyimide-based microelectrode arrays. This allows the use of pre-molded silicone rubber gaskets as dry underfill material and silicone rubber as globtop material. In this work we present the layer deposition approach to solve the difficulties of providing a double-sided, inversely oriented layer stack for an adhering silicon-oxide termination on polyimide substrates. By introducing a sacrificial polyimide layer, we permit high temperature depositions of the required layers allowing a release of the fabricated stack at the desired interface. Long term stable silicone rubber underfill and overcoat is thus achievable despite the use of polyimide substrates. The fabricated samples showed better adhesion to silicone rubber even after storing in phosphate buffered saline (PBS) at 85 °C for 18 hours and at 60°C for 72 hours. The Fourier Transform infrared (FTIR) spectrum also revealed the integrity of the structural stack after detachment from the release layer. The fabrication of double side layer stacks increases the confidence in long term stability of interconnects in polyimide electrodes.
Koch J, Schuettler M, Stieglitz T
Evaluation of design limits for implantable high channel count connectors
2017 Jahrestagung der BIOMEDIZINISCHEN TECHNIK und Dreiländertagung der MEDIZINISCHEN PHYSIK in Dresden, 10. - 13.07.2017

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Pfau J, Stieglitz T, Ordonez JS
Mechanical Deformation and Chemical Degradation of Thin-Film Platinum under Aging and Electrical Stimulation.
2017 8th International IEEE Engineering in Medicine and Biology Society Conference on Neural Engineering” (EMBS NER), 25.5. - 28.5.2017 2017
KurzfassungMiniaturization of electrodes is a prerequisite of selective and targeted interaction with single neurons, enabling more applications in the continuously growing field of neuro- prostheses. Miniaturization in all three dimensions of the elec- trical contact sites should maintain or increase longevity and electrical functionality. The thin-film metallization of the elec- trode site, which is only a couple of hundreds of nanometers thick, has to withstand high chemical load through the corro- sive environment in the body and the electrochemical processes during electrical stimulation in vivo. Platinum (Pt), which is known to be chemically inert and mechanical stable as bulk material shows a lack of chemical and mechanical integrity applied in thin-film microelectrodes. In our study we investi- gated failure mechanisms of thin-film Pt electrodes under con- ditions of electrode aging and electrical stimulation in different physiological media. To understand and eventually overcome stability loss, we investigated the intrinsic structural stress and deformations that arose from mechanical loading through chemical impact and electrical stimulation using optical mi- croscopy and white-light interferometry. Electrochemical measurements indicated oxidation and surface roughening as two of the degradation processes in thin-film electrodes. From the results presumptions about the underlying microstructural changes were made.
Boehler C, Oberueber F, Stieglitz T, Asplund M
Nanostructured platinum as an electrochemically and mechanically stable electrode coating.
2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Seogwipo, 2017 Conf Proc IEEE Eng Med Biol Soc, Band: 2017, Seiten: 1058 - 1061
KurzfassungNanostructured materials exhibit large electrochemical surface areas and are thus of high interest for neural interfaces where low impedance and high charge transfer characteristics are desired. While progress in nanotechnology successively enabled smaller feature sizes and thus improved electrochemical properties, concerns were raised with respect to the mechanical stability of such nano structures for use in neural applications. In our study we address these concerns by investigating the mechanical and electrochemical stability of nanostructured platinum. Neural probes with nano-Pt were exposed to exaggerated stress tests resembling insertion into neural tissue over 60 mm distance or long-term stimulation over 240 M biphasic current pulses. Thereby only insignificant changes in electrochemical properties and morphological appearance could be observed in response to the test, proving that nanostructured platinum exhibits outstanding stability. With this finding, a major concern in using nanostructured materials for interfacing neural tissue could be eliminated, demonstrating the high potential of nanostructured platinum for neuroprosthetic devices.
Erhardt JB, Vomero M, J, Leupold J, Gueli C, Kassegne S, Stieglitz T
Quasi MR-imaging Artefact Free ECoG and Intracortical Electrodes.
2017 Proceedings of the 25th scientific meeting, International Society for Magnetic Resonance in Medicine, Honolulu, USA , Seite: 4429

2016

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Müller M, Jäger J, Stieglitz T
Increasing Active Surface in Picosecond Laser Fabricated Parylene C Electrode Arrays for Intrafascicular Implantation
2016 2016 MRS Fall Meeting, Boston, USA, Material Research Society
KurzfassungPicosecond (ps) laser fabrication offers novel design and fabrication opportunities for implantable electrodes. Through cold ablation metal foils can be thinned down to several µm and subsequently be coated in parylene C. These electrode arrays feature different thicknesses in one assembly to allow simple implantation transversally through a nerve while also offering high structural strength. However, in terms of charge delivery these electrodes have the disadvantage that established electrode coatings like iridiumoxide cannot be used due to incompatible fabrication processes. We introduce controlled corrosion of platinum foils via excessive pulsing as means to increase the active electrode surface to overcome stimulation limitations. The presented electrode arrays have been fabricated from a 25 µm thick platinum iridium foil which was thinned and cut with a LUMERA LASER Rapid10 ps laser system to 10 µm at points of interest. Deposition of Parylene C was carried out within in a SPECIALITY COATINGS SYSTEMS PDS 2010 process chamber. In a first step the electrode arrays were characterized in terms of electrochemical impedance spectroscopy (EIS) with a SOLARTRON 1260&1287 potentiostat and frequency analyzer as well as with a PLEXON PLEXSTIM Electrical Stimulator system for their maximum charge injection capacity. Controlled corrosion was achieved by pulsing the electrodes following a corrosion map for platinum alloys. By setting either the top and/or bottom limit of the voltage response outside the water window different states of passivation, corrosion or platinum black formation were achieved. An increase in maximum charge injection capacity from initially 75 μC/cm2 to 450-550 μC/cm2 could be observed. EIS measurements however showed a change in the underlying electrode model based on the Randles’ cell from a standard R||C-R electrode model towards the appearance of constant phase elements (CPE). Feasibility of removal of electrode material instead of addition of a coating to improve electrochemical behavior in flexible laser fabricated electrode arrays has been shown. However, long term studies have to be conducted to prove stability for medical applications.
Cvancara P, Stieglitz T
The Influence of Temperature on Hydrated Sputtered Iridium Oxide Films
2016 2016 MRS Fall Meeting, Boston, USA, Material Research Society
KurzfassungSputtered iridium oxide films (SIROF) are used mainly for neural stimulation electrodes when high charge injection capacities are desired. In contrast to activated iridium oxide films (AIROF) activation in vivo is not neaded as the iridium oxide is generated during the fabrication process. Though, SIROF electrodes have to be hydrated in vitro via cyclic voltammetry (CV) (with high scan rates and a high number of cycles) to clean the surface and increase the cathodical charge storage capacity (CSCc). We already showed that hot steam sterilization at 134°C reduces the impedance and the CSCc of the hydrated SIROF. It was also proved that pressure has almost no influence on the electrochemical performance. Now we investigated the temperature dependency of hydrated SIROF subject to its electrochemical performance. Consequent we can determine which temperature we should use for sterilizing with hot steam in an autoclave. Thin film electrodes based on Polyimide (PI) as substrate material were fabricated in a class 100 cleanroom using standard lithographic processes. The conduction pathways were made of platinum and the contact sites of SIROF. The openings for the contact sites were realized with reactive ion etching (RIE). The electrodes contained six contact sites with 80 µm in diameter and four with 100 µm respectively. To contact the electrodes electrically a zero insertion force layout and connector was used. We performed measurements on six devices with six contact sites of 80 µm diameter, i.e. 36 contact sites in total. An electrochemical setup with a potentiostat, a Ag/AgCl-reference and a platinum counter electrode was used to perform electrochemical impedance spectroscopy (EIS) and CV of the above described working electrode. First the initial state of the electrodes was acquired and afterwards the electrodes were hydrated. Subsequently the hydrated state was recorded with EIS and CV. Next step was to temper the electrodes at 50°C, 70°C, 90°C, 105°C, 121°C and 134°C for 20 minutes and characterizing the tempered state, again with EIS and CV. Each electrode therefore underwent solely one temperature treatment. The initial resistance of all electrodes was 5.8 kΩ at 1 kHz. After hydration the resistance at 1 kHz dropped to 4.7 kΩ. The tempering at 50°C further decreased the resistance to 4.4 kΩ. The other higher temperatures all led to an increase of the resistance up to 8 kΩ. The tempering of the electrodes at 50°C might release some byproducts from the hydration causing a slight resistance drop. However, the impedances measured via EIS are increasing with increasing temperature. Hence, it is preferable to use lower temperature sterilization processes to achieve good performance of the electrodes, e.g. ethylene oxide (ETO). Publishing Partner mrspartnership Corporate Partners
Langenmair M, Rudmann L, Ordonez JS, Stieglitz T
Development of a desiccant based dielectric for monitoring humidity conditions in miniaturized hermetic implantable packages
2016 BMT Dreiländertagung Basel , Band: 2, Nummer: 1
KurzfassungLifetime estimation of implanted electronics in hermetic packages requires the prediction of the humidity induced lifetime. Classical approaches are limited in applications where miniaturized packages and a buffered humidity at low values are being utilized. An approach to overcome these limitations is described and investigations on suitable materials and measurement setups are presented. The findings support the usability of a Zeolite-silicone based desiccant system as a dielectric for a new type of online sensor. The future exploitation of this new sensing principle can allow the monitoring and prediction of humidity conditions inside of highly reliable miniaturized hermetic implantable packages.

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Khan S, Ordonez J, Stieglitz T
Laser patterned PDMS gasket as voids-free underfill material for implantable biomedical microsystems
2016 2016 11th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT), Taipei, 2016. IEEE Xplore
KurzfassungA pre-cured homogeneous film of silicone rubber (Polydimethyl Siloxane, PDMS) is investigated for application as a gasket-underfill material between flexible polymeric electrodes array and electronics package or interposer for biomedical implants. The gasket is fabricated by structuring a thin sheet of the medical grade MED-1000 silicone with picosecond laser to adapt to the design of interconnections between the electrodes array and the package of implant electronics. The adhesion of the gasket-underfill with the overglazed ceramics (used as test vehicle for package) is evaluated. The application of pre-structured underfill applied prior to electrical bonding ensures voids & bubble-free underfilling and allows for contamination-free interfaces of the mating surfaces. It also eliminates the risk of air or entrapment during underfilling providing which poses a risk for water condensation and short circuiting between contacts. The results of the study show that the gasket with opening size as small as 35 μm with a center-to-center pitch size of 55 μm can be fabricated with the picosecond laser. The gasket-underfill showed sustained adhesion with overglazed ceramics during shear and short term aging tests.
Eickenscheidt M, Stieglitz T
Micro-folding Polyimide Structures for Neural Implants
2016 "Dreiländertagung" Swiss, Austrian  and German Societies of Biomedical Engineering, 4 – 6 .10.2016 , Basel, Schweiz "Dreiländertagung" Swiss, Austrian  and German Societies of Biomedical Engineering
Koch J, Müller M, Schüttler M, Stieglitz T
Towards reliable and resealable multichannel electrical connections in implants: Enhancing conduction and isolation properties in planar contact pad arrays
2016 Dreiländertagung BMT 2016; Swiss, Austrian and German Societies for Biomedical Engineering Biomed Eng-biomed Te, De Gruyter, Band: 61, Nummer: S1, Seiten: 189 - 189
KurzfassungConnectors in implants enable the separation of the stimulator unit from the electrodes offering numerous advantages: enabling the exchange of defect components, facilitation of the implantation procedure and suppression of infections spreading along cables amongst others. The demands on such connec tor systems are high and to some degree contradicting: despite being immersed in body fluid, they have to maintain electrical isolation between individual channels and against their environment while having a high channel density. Furthermore, they should provide an electrical connection with reliable conducting properties that can be opened and closed easily. The better the connection of conducting parts and the tighter the seal around them, the more complicated the opening and reclosing of the connection. Therefore, only few successful systems can be found on the market. However, upcoming generations of neural implants with higher channel counts and yet smaller dimensions require new connector concepts. Former studies revealed that a planar multilayer technology already used for neural electrode arrays comprising silicone and noble metals shows promising results, especially regarding the isolation properties. A noval approach towards implantable high - cha nnel connectors is to bring two arrays of metal pads, recessed in a silicone substrate, face - to - face in close contact to each other. In such a planar design, a strategy is needed to overcome the natural counteraction of isolation structures (the substrate acts as sealing gasket) in order to establish good electrical connections between mating metal pads. In this study, we tested several techniques to enable a reliable electrical connection despite protruding sealing structures using two approaches: first, aiming at the metal pad itself trying to shape or bend it and second aiming at the protrusion of the s urrounding isolation. For each approach, the fabrication process has been adapted and samples have been manufactured and tested for conductive connection of mating metal pad arrays.
Mueller M, Boehler C, Jaeger J, Asplund M, Stieglitz T
A double-sided fabrication process for intrafascicular parylene C based electrode arrays
2016 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) , 16. -20.08.2016, , Orlando, Florida, USA Engineering in Medicine and Biology Society, IEEE, Seiten: 2798 - 2801
KurzfassungAfter the development of a single-sided fabrication process for intrafascicular parylene C based electrode arrays tests showed that an increase in integration density can only be achieved by a double-side process. The process uses 25 μm thick platinum iridium foil, which is thinned down with the laser and sandwiched between two 10 μm thick parylene C layers. Utilizing a picosecond laser (355 nm Nd:YVO4) it was possible to fabricate 40 μm thick electrodes that can be implanted directly in the nerve without relying on additional support layers like chitosan or silk. The fabricated samples feature three 80 μm diameter electrodes on each side and a large ground electrode that is opened to both sides. Impedance mismatches from front to back side as a result of the fabrication process are compensated by electrochemical deposition of nanostructured platinum. This step makes it possible to bring the impedances of the small electrodes down to the range of just a few kΩ at 1 kHz and illustrate the additionally gained surface due to the picosecond laser ablation on the front side electrodes. The safely injectable charge per pulse was found to be 635.75 μC/cm2 for such coated electrodes. Optical investigations show that this fabrication process offers an alternative to established lithographic processes for thin and flexible electrode arrays in neural implants.

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Heizmann S, HolzhammerT, Kilias A, Egert U, Ruther P, Asplund M
Dye delivery from PEDOT electrodes in vivo - a new way to reconstruct recording sites
2016 MEA Meeting 2016, 10th International Meeting on Substrate-Integrated Electrode Arrays, Reutlingen, Germany, 28 Jun - 1 Jul, 2016.

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Cvancara P, Gueli C, Stieglitz T
Laser-Structured Small Ceramic Plates for Reliable Assembly of Commercial Connectors with Customized Cables.
2016 8 th International IEEE EMBS Conference on Neural Engineering, 25. - 28.05.2017, Shanghai, China
KurzfassungThe assembly of active implantable medical devices requires robust and reliable fabrication procedures and methods. In best case, it is free of individual fabrication skills. However, on research level and within fabrication of customized implants, the application of standardized procedures is difficult to realize. A laser-structured and metalized small ceramic plate was designed to reliably interconnect a customized, helically wound 16- channel cable with a commercially available circular Omnetics connector. The small plate enables a more reliable soldering of the single wires to the connector. The application is not restricted to the assembly of cables, but can be easily changed due to the rapid prototyping capability of lasers.
Ghassemi NH, Marxreiter F, Pasluosta CF, Kugler P, Schlachetzki J, Schramm A, Eskofier BM, Klucken J
Combined accelerometer and EMG analysis to differentiate essential tremor from Parkinson's disease.
2016 Conf Proc IEEE Eng Med Biol Soc, Band: 2016, Seiten: 672 - 675
Rudmann L, Ordonez JS, Stieglitz T
Design considerations for miniaturized optical neural probes.
2016 SPIE BiOS, 2016, San Francisco, California, United States Society of Photo-Optical Instrumentation Engineers SPIE Digital Library, Band: 9690, Nummer: March, Seiten: 969025-1 - 969025-5
KurzfassungNeural probes are designed to selectively record from or stimulate nerve cells. In optogenetics it is desirable to build miniaturized and long-term stable optical neural probes, in which the light sources can be directly and chronically implanted into the animals to allow free movement and behavior. Because of the size and the beam shape of the available light sources, it is difficult to target single cells as well as spatially localized networks. We therefore investigated design considerations for packages, which encapsulate the light source hermetically and have integrated hemispherical lens structures that enable to focus the light onto the desired region, by optical simulations. Integration of a biconvex lens into the package lid (diameter = 300 μm, material: silicon carbide) increased the averaged absolute irradiance ηA by 298 % compared to a system without a lens and had a spot size of around 120 μm. Solely integrating a plano-convex lens (same diameter and material) results in an ηA of up to 227 %.
Bisoni L, Mueller M, Cvancara P, Carboni C, Puddu R, Raffo L, Barbaro M, Stieglitz T
Investigation on the hermeticity of an implantable package with 32 feedthroughs for neural prosthetic applications.
2016 Conf Proc IEEE Eng Med Biol Soc, Band: 2016, Seiten: 1967 - 1970
KurzfassungThis paper presents an implantable package aimed at hosting a bidirectional neural interface for neural prosthetic applications. The package has been conceived to minimize the invasivity for the patient, for this reason a cylindrical container with an outer diameter of 7 mm and a length of 21 mm has been designed. The package, realized in alumina (Al2O3), presents 32 hermetic feedthroughs located at the top and bottom base of the cylinder. The hermetic housing has been assembled using a low-temperature soldering method based on a previous platinum/gold (Pt/Au) metallization of the ceramic parts. The package's hermeticity has been successfully proved by means of in-vitro tests, exhibiting an increase in the inner relative humidity of 20 %RH over 75 days of observation.
Rudmann L, Huber SD, Ordonez JS, Stieglitz T
Single-wafer fabricated transparent package lids with integrated lenses enable focusing of light.
2016 Optogen, 3rd International Workshop on Technologies for Optogenetics, Freiburg, 5.- 6.12.2016

2015

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Capogrosso, M, Bonizzato, M, Petrini, F, Raspopovioc, S, Stieglitz, T, Rossini, P.M, Micera, S
Multisensory feedback enables fine force control in a bidirectional prosthetic hand
2015 Society for Neuroscience
HEIZMANN SL, KILIAS A, RUTHER P, EGERT U, ASPLUND M
In vivo tracing of neurons using dye delivery electrodes
2015 Society for Neuroscience: Neuroscience 2015, Chicago, IL
KurzfassungIntroduction: A stable long term monitoring of neuronal signals is essential for the investigation of disorders like epilepsy and Parkinson’s disease. Penetrating microelectrode probes can be inserted in mouse hippocampus and measure local field potentials (LFPs) revealing information about neural network activities in diseased animals. Histological analysis provides additional information about the cell type and status. To correlate LFP recordings with the underlying histology, a precise labelling of neurons in vivo is necessary. However there is a lack of suitable techniques. Therefore a new approach was developed to pinpoint the exact electrode positions in neuronal tissue, using a combined PEDOT/dye system. A conductive PEDOT/PSS coating on top of the recording electrodes allows a controlled exchange of positively charged neurotracer dyes. Defined dye release can thus be triggered at the experimental endpoint after weeks of implantation and limited to the neurons present at the electrode site. Methods: A PEDOT/PSS coating was electrochemically grown on top of iridium oxide (IrOx) recording electrodes integrated in single shaft multielectrode probes. Positively charged dye DiI was incorporated into the PEDOT/PSS layer using an ion exchange method. The coated single shaft multielectrode probe was implanted into mouse hippocampus for LFP recordings. Two weeks after implantation the electrodes were triggered to release the dye. Probes were explanted, the tissue sectioned and the neuronal staining confirmed by fluorescence microscopy. Results: The proof of concept measurements with spectrofluorometry in vitro show the possibility to exchange the neurotracer dye DiI in a PEDOT/dye coating in well controllable mode. A reduced impedance and stable LFP recordings in vivo show the suitability of this approach for recording electrodes. The PEDOT/PSS layer was tested to act as dye reservoir for time periods of weeks. Subsequently the dye can be actively released by electroactivation of the PEDOT/dye system. The released dye locally stained the neurons and allowed a retroactive tracing of electrode positions in hippocampal tissue. Correlation of cell labelling with the probe shaft lesion site was evaluated.
Heizmann SL, Kilias A, Okujeni S, Boehler C, Ruther P, Egert U, Asplund M
Accurate neuronal tracing of microelectrodes based on PEDOT-dye coatings
2015 2015 Montpellier Neural Engineering (NER), 2015 7th International IEEE/EMBS Conference on, Montpellier , Seiten: 386 - 389
KurzfassungPenetrating microelectrode probes offer the opportunity to precisely monitor neuronal signals over several months. After the experimental end point, histological methods are used to analyze the tissue and to correlate recorded signals to histological findings. However, accurate retroactive tracing of the position of individual microelectrodes is currently hampered by the lack of suitable techniques to mark their positions. Here we describe a poly (3, 4-ethylene dioxythiophene) (PEDOT) based microelectrode coating, which is optimized for an active, electrochemically controllable release of the neuronal tracer DiI. The tracer is incorporated into the polymer coating by an ion exchange mechanism. Active cycling showed a 3.6 times higher dye incorporation rate compared to reference samples which were solely immersed in the dye. A bi-layer system was used to optimize drug storage ability and could suppress passive leakage of DiI from the film by more than a factor 6. The PEDOT/dye system was characterized in vitro in terms of its ability to store the dye over the time course of the experiment, deliver a precise quantity upon electroactivation and continuously support stable recordings throughout an implantation.
del Valle, J, de la Oliva, N, Müller, M, Stieglitz, T, Navarro, X
Biocompatibility evaluation of parylene C and polyimide as substrates for pe-ripheral nerve interfaces
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier , Seiten: 442 - 445
Maciejasz, P, Badia, J, Souquet, G, Cvancara, P, Picq, C, Stieglitz, T, Navarro, X, Guiraud, D
Decreasing Stimulation Charge by Delaying the Discharge Phase -Comparison of Efficacy for Various Stimulation Waveforms
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier , Seiten: 402 - 405
Mueller, M, Ulloa, M, Schuettler, M, Stieglitz, T
Development of a Single-Sided Parylene C Based Intrafascicular Multichannel Electrode for Peripheral Nerves
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier , Seiten: 537 - 540
Fiedler, E, Porto Cruz, M. F, Cota Monjarás, O. F, Stieglitz, T
Evaluation of Thin-film Temperature Sensors for Integration in Neural Probes.
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier, Frankreich IEEE, Seiten: 22 - 24
KurzfassungIn situ monitoring of tissue temperature during in vivo experiments can be of great advantage. It could allow the detection of inflammation development and possible infections caused by the implanted devices, the prevention of overheating due to electrical or optogenetical stimulation and the recording of effected vasodilation and increased metabolism. In this work, we present the characterization of platinum temperature sensors integrated in thin-film polyimide substrates. Three different sensor types were fabricated, with the intent to match a Pt 100, a Pt 1000 and a Pt 5000, all of them showing the typical characteristic curve of platinum for the electrical resistance as a function of temperature. Sensitivities of 0.2 Ω/°C, 1.7 Ω/°C and 8.8 Ω/°C were determined for the different sensor types. With the Pt 5000 samples temperature changes of less than 0.5 °C could be detected reliably, independent of the ambiance being air or water. Good in vivo behavior of the platinum sensors is assumed as the fabrication process was not altered compared to established polyimide-based electrode arrays.
Hassler, C, Ehler, N, Singh, V, Xie, Y, Martini, N, Kirch, R.D, Prucker, O, Rühe, J, Hofmann, U.G, Stieglitz, T
Fabrication and Implantation of Hydrogel Coated, Flexible Polyimide Elec-trodes
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier , Seiten: 561 - 654
Ashouri Vasari, D.,, Ordonez, J.S., Furlanetti, L.,, Döbrössy, M, Coenen, V.,, Stieglitz,T.
Hybrid Multimodal Deep Brain Probe (DBS array) for Advanced Brain Re-search
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier , Seiten: 410 - 413
Cota, O.F, Plachta, D, Stieglitz, T, Manoli, Y, Kuhl, M.
In-vivo characterization of a 0.8-3µVRMS input-noise versatile CMOS pre-amplifier
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier
KurzfassungAbstract: The following work presents a CMOS-integrated low-noise pre-amplifier (LNA) for bio-potential recordings, which is part of a multi-channel neural recording system. The versatile pre-amplifier channel features a tunable lower cut-off frequency from 0.2 Hz to 10 kHz, an upper cut-off frequency from 37.9 Hz to 11 kHz, and a middle-band gain from 41 to 45 dB. With its variable power consumption from 3.3 μW to 1 mW, the input-referred noise can be set from 2 down to 0.8 μVRMS. The pre-amplifier, fabricated in a 0.35 μm CMOS process, was successfully tested for ECG, EMG, and EEG applications.
Boehler, C, Oberueber, F, Stieglitz, T, Asplund, M.
Iridium Oxide (IrOx) serves as adhesion promoter for conductiong polymers on neural microelectrodes
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier , Seiten: 410 - 413
Somerlik-Fuchs, K.H, Hofmann, U.G, Stieglitz, T, Schulze-Bonhage, A
The Influence of Stimulation Parameters on the Relative Phase Clustering Index
2015 Index7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier , Seiten: 898 - 901
Cota, O.F, Schlösser, M, Schieck, M, Stieglitz, T, Gierthmuehlen, M, Plachta, D T T
iNODE in-vivo testing for selective vagus nerve recording and stimulation
2015 7th Annual International IEEE EMBS Conference on Neural Engineering Montpellier
KurzfassungHypertension is a wide spread disease and despite pharmacological treatment some patients cannot obtain any relief from medication. In previous work, we could show that blood pressure can be reduced by Vagus Nerve Stimulation (VNS) almost free from side effects. In this work, we focus on the implementation of a miniaturized system using a modified embedded sensor/actuator device iNODE for vagus nerve recording and stimulation. The results illustrate that this device, using a 3.3 V power supply, 58.9 mW while stimulating, 7.8 mW while recording, is capable of reducing the blood pressure, showing equivalent results to major laboratory equipment.
Rudmann L, Huber SD, Ordonez JS, Stieglitz T
Fused silica microlenses for hermetic packages as part of implantable optrodes.
2015 Conf Proc IEEE Eng Med Biol Soc, Band: 2015, Seiten: 7143 - 7146
Rudmann L, Huber SD, Ordonez JS, Stieglitz T
Heat treatment of photoresist to fabricate customized microlenses for implantable hermetic micropackages.
2015 DGBMT Deutsche Gesells. für Biomedizinische Technik im VDE, University of Lübeck, 2015
Erhardt JB, Leupold J, Fuhrer E, Gruschke OG, Wapler MC, Hennig J, Korvink JG, Stieglitz T
Influence of Pt/Ir electrode thickness on magnetic resonance imaging susceptibility artefacts
2015 49th annual conference of DGBMT 2015, Lübeck , DGBMT Deutsche Gesells. für Biomedizinische Technik im VDE University of Lübeck
KurzfassungInfluence of Pt/Ir electrode thickness on magnetic resonance imaging susceptibility artefacts Introduction Magnetic resonance imaging (MRI) is already one of the most important diagnostic tools in medicine and its importance and application is still growing , especially for clinical diagnosis in patients with implants. In active implantable medical devices, metal structures such as electrodes can impair MRI results in the vicinity of the neuronal structu res of interest . The size of these imaging artefacts around electrodes play an important role for postoperative electrode localization used for the verification of successful placement. Dimensions of imag ing artefacts depend on material, structure, geom- etr y and orientation of the imaged object . Therefore the correlation of imaging artefact size caused by Pt/Ir electrode structures and the thickness of these electrode structures was investigated . Methods A 25 μm thick Pt/Ir foil (Goodfellow) was structured with a Rapid10 picosecond - laser (Lumera Laser), resulting in 750 μm in diameter disc shape d electrode - like samples. To realize 6 different sample hights laser ablation across the entire disc surface was appl i ed . Thereafter, t he discs were placed on 30 μm t hick silicone rubber to serve as substrate for MRI and scanning electr on microscopy (SEM) examination. A 9.4 T Bruker BioSpec 94/21 imaging system was used for MRI acquisition. Results Laser ablation proved to be a reproducible m ethod for structuring elect rode shape and thickness, which was verified us- ing SEM. The MRI examination of the Pt/Ir discs show ed a linear correlation between imaging artefact size and Pt/Ir disc thickness. Conclusion The imaging artefact size of 750 μm in diameter and 25 μm thick P t/Ir discs could successfully be reduced by decreas- ing the sample hight using laser ablation across the entire sample surface . Therefore, p ostoperative electrode placement verification may get more precis e and facilitated by reducing the imaging artefact size with thinner metal layers in im- plants. Still, m ore studies on the influen c e of structure and geometry of electrodes need to be performed.
M.T. Alt, T. Stieglitz
Investigations for Wafer-level Integration of Thin Glass for Waveguides in Long-Term Stable Implants.
2015 49th annual conference of DGBMT 2015, Lübeck , DGBMT Deutsche Gesells. für Biomedizinische Technik im VDE University of Lübeck
KurzfassungIntroduction Optogenetics have enabled new possibilities in neuroscience during the last years . However, the development of suitable micro - optrodes still needs to be improved and often lacks in fulfilling important requirements such as l ong - term stability or miniaturization . This work presents an approach for developing test struc tures for implantable optrodes using wafer - level microtechnology and thin glass substrates for multimode waveguides and packages. Methods A 25 μm thin aluminum - borosilicate glass was chosen as a substrate. Different cleaning processes (O 2 - p lasma, H 2 O 2 , H 2 SO 4 , HCl, standard solvents) were tested to remov e all particles fro m the glass’ surface. The average amount of particles on the glass surface was determined for each test ed proces s by means of optical inspection in defined fields on the sub- strate . A wafer - level process was developed based on glass foils and silicon wafers. Waveguides were designed using the thin glass substrate as core and SiO 2 layers as cladding material. A SiO 2 layer was deposited on a silicon wafer with plasma enhanced chemical vapor deposition (PECVD). Afterwards, the glass was bonded to the wafer. Photolithography and reactive ion etching were used to structure the layers. A second layer of PECVD SiO 2 covers the waveguides and closes the cladding. The roughness of the waveguide’s end facets was examined using scanning electron microscopy. Results The fragility of the glass foils limits the applicability of different cle aning procedures. Applying ultrasound to the wet cleaning processes enhanced the cleaning results , especially with combined etchants and was found to remove more particles than dry cleaning. Clean surfaces allowed successful bonding of the glass to the wafer. Conclusion T hin glass foils could suc cessfully be integra ted in the wafer - level process for developing microtechnical optrodes . T his process could be used to realize hermetic micro - packages with integrated waveguides for long - term stable implantable optrodes using wafer level packaging
Rehberger F, Fiedler EM, Cota Monjarás OF, Stieglitz T
Lichtwellenleiter aus PDMS für biomedizinische Anwendungen
2015 49th annual conference of DGBMT 2015, Lübeck , DGBMT Deutsche Gesells. für Biomedizinische Technik im VDE, University of Lübeck
Ordonez JS, Rudmann L, Cvancara P, Bentler C, Stieglitz T
Mechanical deformation of thin film platinum under electrical stimulation.
2015 Conf Proc IEEE Eng Med Biol Soc, Band: 2015, Seiten: 1045 - 1048
KurzfassungThin-film-based electrodes used to interact with nervous tissue often fail quickly if used for electrical stimulation, impairing their translation into long-term clinical applications. We initiated investigations about the mechanical load on thin-film electrodes caused by the fact of electrical stimulation. Platinum electrodes of Ø 300μm on a polyimide carrier were subjected to approximately 50 000 asymmetrical, biphasic stimulation pulses in vitro. The electrode's surface was investigated optically by means of white-light interferometry. The structural expansion for the metallic surface subjected to stimulation was measured to reach roughly 30%. The study points towards a failure mechanism of thin-films being of mechanical nature, inherent to the unavoidable electrochemical processes involved (change in lattice constants) during electrical stimulation at the electrode's surface. Based on further scientific facts, we set 3 hypotheses for the exact mechanisms involved in the failure of thin-films used for electrical stimulation, opening a new door for research and improvement of novel neuroprosthetic devices.
Rudmann L, Huber SD, Ordonez JS, Stieglitz T
Mikrolinsen für implantierbare Optroden.
2015 MikroSystemTechnik Kongress 2015 , Seiten: 81 - 84
Richer R, Maiwald T, Pasluosta C, Hensel B, Eskofier BM
Novel human computer interaction principles for cardiac feedback using google glass and Android wear
2015 2015 IEEE 12th International Conference on Wearable and Implantable Body Sensor Networks, BSN 2015
Fiedler EM, Rehberger F, Stieglitz T
PDMS-based Laser-structured Optical Waveguides for Neural Probes.
2015 49th annual conference of DGBMT 2015, Lübeck , DGBMT Deutsche Gesells. für Biomedizinische Technik im VDE, University of Lübeck
Pasluosta Cristian, Gassner Heiko, Winkler Juergen, Klucken Jochen, Eskofier Bjoern
Parkinson’s disease as a working model for global healthcare restructuration: the Internet of Things and wearables technologies
2015 Proceedings of the 5th EAI International Conference on Wireless Mobile Communication and Healthcare, Seiten: 162 - 165
Pasluosta CF, Barth J, Gassner H, Klucken J, Eskofier BM
Pull Test estimation in Parkinson's disease patients using wearable sensor technology.
2015 Conf Proc IEEE Eng Med Biol Soc, Band: 2015, Seiten: 3109 - 3112
Mullan P, Kanzler CM, Lorch B, Schroeder L, Winkler L, Laich L, Riedel F, Richer R, Luckner C, Leutheuser H, Eskofier BM, Pasluosta C
Unobtrusive heart rate estimation during physical exercise using photoplethysmographic and acceleration data.
2015 Conf Proc IEEE Eng Med Biol Soc, Band: 2015, Seiten: 6114 - 6117

2014

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Mueller, M, Kohler, F, Ordonez, J.S, Stieglitz, T, Schuettler, M
Fabrication of flat electrodes utilizing picosecond laser manufacturing technology
2014 IFESS
Stieglitz, T, Ordonez, J.S, Hassler, C, Fiedler, E, Kohler, F, Boretius, T, Boehler, C, Asplund, M, Schuettler, M
Flexible Polymer-based Neuroprosthetic Interfaces in Fundamental and Translational Research
2014 Symposium on Advanced Multifunctional Biomaterials for Neuroprosthetic Inter-faces , MRS Spring,
Micera S, Raspopovic S, Capogrosso M, Carpaeto J, Ganata G, Oddo C.M, Cipriani C, Stieglitz T, Schuettler M, Navarro X, Raffo L, Barbaro M, Rossini P M
Neurocontrolled bidirectional artificial upper limb and hand prosthesis (NEBIAS)
2014 30th Int. COngress Clin. Neurophysiol. (ICCN) Berlin
Bertotti G, Dodel N, Keil S, Wolansky D, Tillak B, Schreiter M, Eickenscheidt M, Zeck G, Stett A, Möller A
A capacitively-coupled CMOS-MEA with 4225 recording sites and 1024 stimulation sites
2014 Int. Meeting on Substrate-Integrated Microelectrodes, Reutlingen, Germany , Band: 9
Kohler F, Kiele P, Ordonez JS, Stieglitz T, Schuettler M
A polymer-metal two-step concept for hermetic neural implant packages
2014 Chicago IEEE, Band: 36, Seiten: 113 - 116
Fuhrer E, Erhardt JB, Gruschke O, Wapler MC, Fakhrabadi M, Müller M, Göbel K, LeVan P, Stieglitz T, Wallrabe U, Henning J, Korvink JG
Can patients with brain implants undergo MRI?
2014 48 th Annual Conference of the German Society for Biomedical Engineering 8.-10.10.2014, Hannover Biomed Tech, VDE, Band: 59, Nummer: 51
Rudmann L, Ordonez JS, Zappe H, Stieglitz T
Hermetic Electrical Feedthroughs Based on the Diffusion of Platinum into Silicon.
2014 47 th International Symposium on Microelectronics, October 13-16th, 2014, San Diego, CA, USA , Band: 2014, Nummer: 1, Seiten: 000729 - 000734
KurzfassungWithin this paper a novel approach for the development of hermetic electrical feedthroughs is introduced. So far, every vertical feedthrough induces at the feedthroughs' interfaces possible paths for water to leak across the hermetic barrier into the hermetic package. The presented approach is based on the diffusion of platinum into silicon, locally changing the electrical behavior of the substrate due to the induced impurities. This method avoids destroying the bulk material, in this case silicon, preserving the hermetic barrier environment. Different n-type silicon substrates were investigated for their usability through various diffusion experiments under two gas atmospheres: Argon/hydrogen and pure nitrogen. A significant change in silicon behavior could be shown for one of the used substrates. The current flowing through the bulk could be decreased by a factor of around 12 for an argon/hydrogen atmosphere and by around 10 for pure nitrogen. The current directly correlates with a local increase of the substrates' resistance, demonstrating the possibility of adapting the electrical properties of a substrate to create insulating areas within a conductive substrate.
Xie Y, Hassler C, Stieglitz T, Seifert A, Hofmann UG
In-situ monitoring of brain tissue reaction of chronically implanted electrodes with an optical coherence tomography fiber system
2014 Proc. of SPIE, Seiten: 1 - 7
Xie Y, Martini N, Hassler C, Kirch RD, Stieglitz T, Hofmann UG
Online monitoring of neuroinflammation induced by chronic implanted microelectrode using a fiber-based OCT
2014 Proc. 48th Annual Conference of the German Society for Biomedical Engineering
Boehler C, Stieglitz T, Asplund M
Platinum Nano-Grass: Add-On Functionalization for Implantable Microelectrodes
2014 Materials Research Society Spring Meeting 2014
Asplund M, Boehler C, Heizmann S, Egert U, Hofmann U, Stieglitz T
Polymer electrodes for drug release during stimulation
2014 DGBMT 2014 Hannover

2013

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Wang,X, Gkogkidis, A, Gierthmuehlen, M, Freimann, T.M, Henle, C, Raab, M, Fischer, J, Fehrenbacher, T, Kohler, F, Foerster, K, Haberstrooh, J, Schulze-Bonhage, A, Aertsen, A, Stieglitz, T, Schuettler, M, Rickert, J, Ball, T.
Acute and chronic µECoG-based brain mapping using a wireless implant system in a large animal model
2013 Society for Neuroscience
Rickert, J, Kohler, F, Fischer, J, Fehrenbacher, T, Gkogkidis, A, Mohrlock, R, Paetzold, J, Boven, K.-H, Henle, C, Meier, W, Raab, M, Ordonez, J.S, Wang, X, Gierthmuehlen, M, Ball, T, Foerster, K, Haberstroh, J, Freimann, T.M, Stieglitz, T, Schuettler, M
An implantable brain-computer interface for chronic cortical recording and sti-mulation using a micro-ECoG electrode array
2013 Society for Neuroscience
Gierthmuehlen, M, Wang, X, Kuehn, C, Gkogkidis, A, Henle, C, Raab, M, Fischer, J, Kohler, F, Haberstroh, J, Stieglitz, T, Schuettler M, Rickert, J, Ball, T, Freimann, T.M
Neurosurgical approach to the cerebral cortex for acute and chronic cortical sti-mulation and recording studies in minipigs and sheep
2013 Society for Neuroscience
Christ O, Somerlik-Fuchs KH, Stieglitz T, Schulze-Bonhage A, Hofmann UG
Prescreening Seizure-like Events in a Rat Model of Epilepsy B: A 3D Online Video Processing Method
2013 San Diego, USA, Nov 6-8, 2013 Proc IEEE-EMBS Neural Eng Conf, IEEE, Seiten: 1242 - 1245
Kohler F, Ulloa Suarez M, Ordonez J, Stieglitz T, Schüttler M
Reliability Investigations and Improvements of Interconnection Technologies for the Wireless Brain-Machine Interface - 'BrainCon'
2013 San Diego, USA, Nov 6-8 6th IEEE-EMBS Conference on Neural Engineering, Seiten: 1013 - 1016
Schuettler, M, Kohler, F, Fischer, J, Fehrenbacher, T, Gkogkidis,A, Mohrlok, R, Paetzold, J, Boven, K.-H, Moeller, A, Henle, C, Meier, W, Raab, M, Ordonez, J.S, Wang, X, Gierthmuehlen, M, Ball, T, Foerster, K, Haberstroh, J, Freiman, T.M, Stieglitz, T, Rickert, J
An Implant for Closed-Loop ECoG Recording and Stimulation
2013 11th World Congress of the International Neuromodulation Society
Stieglitz, T, Rubehn, B, Boretius, T, Henle, C, Ordonez, J, Meier, W, Hassler, C, Boehler, C, Kohler, F, Schuettler, M
Interfacing with the Nervous System
2013 11th World Congress of the International Neuromodulation Society. Pre-conference workshop
Ordonez J, Bentler C, Keller M, Schüttler M, Stieglitz T
High Density Hermitic Feedthroughs - Design Aspects for Reliability
2013 IMAPS UK, Cambridge
Boehler C, Stieglitz T, Asplund M
Design and evaluation of PEDOT:Dex based drug delivery coatings for neural implant electrodes.
2013 2013 Materials Research Society Spring Meeting 2013
Schüttler M, Ulloa Suarez M, Ordonez J, Stieglitz T
Laser Fabrication of Neural Electrode Arrays with Sputtered Iridium Oxide Film
2013 IEE EMBS NER
Schuettler M, Ulloa M, Ordonez J, Stieglitz T
Laser-Fabrication of Neural Electrode Arrays with Sputtered Iridium Oxide Films
2013 San Diego, USA, Nov 6-8, 2013 Proc IEEE-EMBS Neural Eng Conf, Seiten: 1171 - 1173
Fiedler E, Ordonez J, Stieglitz T
Modular Assembly of Flexible Thin-Film Electrod Arrays Enabled by a Laser-Structured Ceramic Adapter
2013 IEE EMBS NER
Ordonez J, Boehler C, Schuettler M, Stieglitz T
Silicone Rubber and Thin-Film Polyimide for Hybrid Neural Interfaces - A MEMS-based Adhesion Promotion Technique
2013 Proceedings of the IEEE-EMBS Neural Eng Conf., San Diego, USA, Nov 6-8, 2013 Proc IEEE-EMBS Neural Eng Conf, Seiten: 872 - 875
Boretius T, Stieglitz T
The Influence of Hot-steam Sterilization on Hydrated Sputtered Irdium Oxide Films
2013 San Diego, USA, Nov 6-8, 2013 Proc IEEE-EMBS Neural Eng Conf, Seiten: 279 - 282

2012

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Stieglitz T, Ordonez J, Boretius T, Kohler F, Schüttler M
From Interfaces to Implants - Developments towards High Channel Neural Devices
2012 Proceedings of the International Functional Electrical Stimulation Society Conference, Alberta, Canada IFESS, Seiten: 1 - 4
Harreby, K. R, Kundu, A, Geng, B, Maciejasz, P, Guiraud, D, Stieglitz, T, Boretius, T, Yoshida, K, Jensen, W
Recruitment Selectivity of Single and Pairs of Transverse, Intrafascicular, Multi-channel Electrodes (TIME) in the Pig Median Nerve
2012 17th Annual Meeting Functional Electrical Stimulation Society 17th Annual Meeting Functional Electrical Stimulation Society, IFESS
Boretius T, Yoshida K, Badia J, Harreby K, Kundu A, Navarro X, Jensen W, Stieglitz T
A Transverse Intrafascicular Multichannel Electrode (TIME) to Treat Phantom Limb Pain – Towards Human Clinical Trials
2012 IEEE International Conference on Biomedical Robotics and Biomechatronics, Seiten: 282 - 287
Jensen W, Micera S, Navarro X, Stieglitz T, Guiraud D, Divoux J, Rossini P M, Yoshida K
Transverse Intrafascicular Multichannel Electrode (TIME) system for induction of sensation and treatment of phantom limb pain in amputees.
2012 6th Concertation and Consultation Workshop of projects in Micro-Nano-Bio convergence Systems (MNBS), Seite: 3
Stieglitz T, Boretius T, Ordonez JS, Schuettler M
Minaturized Neural Interfaces and Implants
2012 Conference on Microfluidics, BioMEMS, and Medical Microsystems X, At San Francisco, USA Proceedings of SPIE, The International Society for Optical Engineering, Band: 8251, Nummer: 9
KurzfassungNeural prostheses are technical systems that interface nerves to treat the symptoms of neurological diseases and to restore sensory of motor functions of the body. Success stories have been written with the cochlear implant to restore hearing, with spinal cord stimulators to treat chronic pain as well as urge incontinence, and with deep brain stimulators in patients suffering from Parkinson's disease. Highly complex neural implants for novel medical applications can be miniaturized either by means of precision mechanics technologies using known and established materials for electrodes, cables, and hermetic packages or by applying microsystems technologies. Examples for both approaches will be introduced and discussed. Electrode arrays for recording of electrocorticograms during presurgical epilepsy diagnosis have been manufactured using approved materials and a marking laser to achieve an integration density that is adequate in the context of brain machine interfaces, e.g. on the motor cortex. Microtechnologies have to be used for further miniaturization to develop polymer-based flexible and light weighted electrode arrays to interface the peripheral and central nervous system. Polyimide as substrate and insulation material will be discussed as well as several application examples for nerve interfaces like cuffs, filament like electrodes and large arrays for subdural implantation.
Stieglitz T, Boretius T, Ordonez J, Hassler C, Henle C, Meier W, Plachta D T T, Schuettler M
Miniaturized neural interfaces and implants
2012 Medical and Diagnostic Applications, Band: 8251, Seiten: 1 - 12
Schuettler M, Kohler F, Fischer J, Mohrlok R, Paetzold J, Boven K-H, Moeller A, Henle C, Meier W, Raab M, Fehrenbacher T, Ordonez JS, Plachta D, Wang X, Giertmuehlen M, Ball T, Foerster K, Haberstroh J, Freiman T, Stieglitz T, Rickert J
BrainCon - An Implantable Wireless Brain-Machine Interface for Chronic Cortical Recording and Stimulation
2012 IEEE EMBC 2012, Seiten: 26 - 26
Schüttler M, Kohler F, Ordonez J, Stieglitz T
Hermetic Electronic Packaging of an Implantable Brain-Machine Interface with Transcutaneous Optical Data Communication
2012 , Seiten: 3886 - 3889
Schuettler M, Kohler F, Ordonez JS, Stieglitz T
Hermetic Electronic Packaging of an Implantable Brain-Machine-Interface with Transcutaneous Optical Data Communication
2012 34th Annual International Conference of the IEEE EMBS, San Diego, California, USA, 28 August - 1 September, 2012, Seiten: 3886 - 3889
Ordonez J, Dautel P, Schuettler M, Stieglitz T
Hermetic Glass Soldered Micro-Packages for a Vision Prosthesis
2012 San Diego, USA Conf Proc IEEE Eng Med Biol Soc., Seiten: 2784 - 2787
Ordonez JS, Boehler C, Schuettler M, Stieglitz T
Improved Polyimide Thin-Film Electrodes for Neural Implants
2012 San Diego, USA IEEE EMBS 2012, Seiten: 5134 - 5137
Ordonez J S, Boehler C, Schuettler M, Stieglitz T
Long-term Adhesion Studies of Polyimide to Inorganic and Metallic Layers
2012 MRS Proceedings, Band: 1466
Kohler F, Schuettler M, Stieglitz T
Parylene-Coated Metal Tracks for Neural Electrode Arrays – Fabrication Approaches and Improvements Utilizing Different Laser Systems
2012 IEEE EMBS 2012, Seiten: 5130 - 5133
Eickenscheidt Max, Zeck Günther
Repetitive capacitive stimulation of the retina in a stack-configuration
2012 Int. Meeting on Substrate-Integrated Microelectrodes, Reutlingen, Germany , Band: 7, Seite: 188

2011

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Stieglitz T, Rubehn B, Boretius T, Henle C, Ordonez J, Meier W, Hassler C, Schuettler M
Flexible and compliant interfaces to the peripheral and central nervous system
2011 MRS Fall Meeting, Symposoium R: Compliant Electronics and Photonics
Ordonez JS, Keller M, Schuettler M, Guenther T, Wilde J, Suaning GJ, Stieglitz T
Hochintegrierte hermetische Durchführungen für implantierbare Neuroprothesen
2011 Proc. Mikrosystemtechnik Kongress
Rubehn B, Stieglitz T
Polymerbasierte neuronale Mikroelektrod mit iuntegriertem Lichtwellenleiter
2011 Proc. Mikrosystemtechnik Kongress
Kohler F, Schuettler M, Ordonez JS, Stieglitz T
Laser Microfabrication of Neural Electrode Arrays: Comparison of Nanosecond and Picosecond Laser Technology
2011 16th IFESS Annual Conference, 2011
Stieglitz T, Schuettler M, Rubehn B, Boretius T, Badia J, Navarro X
Evaluation of Polyimide as Substrate Material for Electrodes to Interface the Peripheral Nervous System
2011 Cancun, Mexico Proc. of the IEEE-EMBS Neural Eng Conf., Seiten: 529 - 533
Schuettler M, Schroeer S, Ordonez J, Stieglitz T
Laser-fabrication of Peripheral Nerve Cuff Electrodes with Intetgrated Microfluidic Channels
2011 Cancun, Mexico Proc. of the IEEE-EMBS Neural Eng Conf., Seiten: 545 - 548
Somerlik KH, Cosandier-Rimélé D, Cordeiro JG, Krueger TB, Mattmueller R, Stieglitz T, Aertsen A, Schulze-Bonhage A
Measuring epileptogenicity in kainic acid injected rats
2011 Proc. of the IEEE-EMBS Neural Eng Conf.
Jensen W, Micera S, Navarro X, Stieglitz T, Guiraud D, Divoux J, Rossini PM, Yoshida K
Transverse Intrafascicular Multichannel Electrode (TIME) system for induction of sensation and treatment of phantom limb pain
2011 5th Consultation workshop on Micro-Nano-Bio Convergence Systems – MNBS 2011
Stieglitz T, Boretius T, Navarro X, Badia J, Guiraud D, Divoux J-L, Micera S, Rossini PM, Yoshida K, Jensen W
Development on an implantable system for relieving phantom pain using transversal intrafascicular electrodes (TIME)
2011 Proc. Technically Assisted Rehabilitation (TAR)
Ordonez J, Keller M, Schuettler M, Guenther T, Suaning G, Wilde J, Stieglitz T
High-density hermetic feedthroughs for multi-channel implantable electronics
2011 Proc. Technically Assisted Rehabilitation (TAR)
Jin Y-H, Daubinger P, Fiebich BL, Stieglitz T
A novel platinum nanowire-coated neural electrode and its electrochemical and biological characterization
2011 IEEE MEMS Conference
Taylor J, Schüttler M, Clarke C, Donaldson N
A Summary of the Theory of Velocity Selective Neural Recording
2011 33rd Annual International Conference of the IEEE EMBS, IEEE, Seiten: 4649 - 4652
KurzfassungThis paper describes improvements to the technique of velocity selective recording (VSR) in which multiple neural signals are matched and summed to identify excited axon populations in terms of velocity. This form of recording has been termed intrinsic velocity selective recording (IVSR). The signals are acquired using a multi-electrode cuff (MEC) which is now available as a component for use in implantable neuroprostheses. The improvements outlined in the paper involve the use of bandpass filters at the output of the system which allows a higher level of selectivity to be obtained than is possible using IVSR.

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Kundu A, Harreby KR, Kurstjens M, Boretius T, Stieglitz T, Yoshida K, Jensen W
Comparison of acute stimulation selectivity of transverse and longitudinal intrafascicular electrodes in pigs
2011 Society for Neuroscience
Harreby KR, Kundu A, Boretius T, Stieglitz T, Yoshida K, Jensen W
Evaluation of the stimulation selectivity of transverse intrafascicular multichannel electrodes in the chronic Göttingen mini-pig - preliminary results
2011 Society for Neuroscience
Pasluosta CF, Dua P, Lukiw WJ
Nearest hyperplane distance neighbor clustering algorithm applied to gene co-expression analysis in Alzheimer's disease.
2011 Conf Proc IEEE Eng Med Biol Soc, Band: 2011, Seiten: 5559 - 5562

2010

nach oben zur Jahresübersicht

Jin Y-H, Daubinger P, Stieglitz T
A Novel Platinum Nanowire Coating on Neural Electrode and its Impedance Characterization
2010 MRS Fall Symposium, Boston, MA, USA
Rubehn B, Stieglitz T
Mechanical Long-Term Stability of Polyimide as a Material for Neural Implants
2010 MRS Fall Symposium, Boston, MA, USA
Schuettler M, Stieglitz T
Implantierbare Neuroprothesen zur Funktionellen Elektrostimulation - Stand der Technik und aktuelle Forschungstrends
2010 6. Jahrestagung der Deutschen Gesellschaft für Neuromodulation (DGNM), Luxemburg
Stieglitz T, Huang W, Chen SC, Morley JW, Lovell NH, Suaning GJ
A Transparent Electrode Array for Simulataneous Cortical Potential Recording and Intrinsic Signal Optical Imaging
2010 32nd Annual International Conference of the IEEE EMBS, Buenos Aires Argentina
Schuettler M, Huegle M, Ordonez JS, Wilde J, Stieglitz T
A device for vacuum drying, inert gas backfilling and solder sealing of hermetic implant packages
2010 32nd Annual International Conference of the IEEE EMBS, Buenos Aires Argentina
Jensen W, Micera S, Navarro X, Stieglitz T, Guiraud D, Divoux JL, Rossini PM, Yoshida K
Development of an implantable transverse intrafascicular multichannel electrode (TIME) system for relieving phantom limb pain
2010 Annual International Conference of the IEEE EMBS, Buenos Aires Argentina
Suaning GJ, Kisban S, Chen SC, Byrnes-Preston P, Dodds C, Matteuc-ci P, Herwik S, Morley JW, Lovell NH, Paul O, Stieglitz T, Ruther P
Discrete Cortical Responses from Multi-Site Supra-Choroidal Electrical Stimu-lation of the Feline Retina
2010 32nd Annual International Conference of the IEEE EMBS, Buenos Aires Ar-gentina
Schuettler M, Ordonez JS, Silva Santisteban T, Schatz A, Wilde J, Stieglitz T
Fabrication and Test of a Hermetic Miniature Implant Package with 360 Electrical Feedthroughs
2010 32nd Annual International Conference of the IEEE EMBS, Buenos Aires Argentina
Bossi S, Benvenuto A, Wieringa P, DiPino G, Gugliemelli E, Boretius T, Stieglitz T, Navarro X, Micera S
Preliminary investigations on laminin coatings for flexible polyimide/platinum thin films for PNS applications
2010 32nd Annual International Conference of the IEEE EMBS, Buenos Aires Argentina
Bosman CA, Womelsdorf T, Oostenveld R, Rubehn B, De Weerd P, Stieglitz T, Fries P
252-site subdural LFP recordings in monkey reveal large-scale effects of selective attention
2010 FENS Forum, Amsterdam, NL FENS Abstr, Band: 5, Seite: 139.1
Micheli C, Bosman CA, Womelsdorf T, Oostenveld R, Rubehn B, De Weerd P, Stieglitz T, Fries P
Combining high-density electrocorticography (ECoG) in macaque monkey with source reconstruction
2010 FENS Forum, Amsterdam, NL FENS Abstr, Band: 5, Seite: 139.13
Ordonez J, Schuettler M, Rubehn B, von Metzen R, Henle C, Boretius T, Stieglitz T
Technologies for Implantable Devices
2010 2nd Indo German Frontiers of Engineering Symposium, Potsdam, Germany
Jensen W, Micera S, Navarro X, Stieglitz T, Guiraud D, Divoux J, Rossini PM, Yoshida K
Transverse Intrafascicular Multichannel Electrode (TIME) system for treatment of phantom limb pain in amputees
2010 XVIII Congress of the International Society of Electrophysiology and Kinesiology, Aalborg, Denmark
Wang X, Gierthmühlen M, Henle C, Raab M, Stieglitz T, Kaminsly J, Ball T
Brain mapping using μECoG signals in the 250-400 Hz band
2010 16th Annual Meeting of the Organization for Human Brain Mapping, Barcelona
Bosman C, Womelsdorf T, Oostenveld R, Rubehn B, de Weerd P, Stieglitz T, Fries P
252-site subdural LFP recordings in monkey reveal large-scale effects of selection attention
2010 Computational and Systems Neuroscience (COSYNE), Salt Lake City, UT, USA
Bosman C, Womelsdorf T, Oostenveld R, Rubehn B, de Weerd P, Stieglitz T, Fries P
252-site subdural LFP recordings in monkeys unveil dynamical inteareal communication modulated by selective attention
2010 Society for Neuroscience
Rubehn B, Stieglitz T
A Flexible Neural Shaft Electrode with Integrated Optical Waveguide
2010 Biomed Tech, Band: 55, Ergänzungsband: 1
Henle C, Madjarov A, Schuettler M, Stieglitz T
Evaluation of Cytotoxicity on Laser-Fabricated Neural Implants: Influence of Different Manufacturing Processes and Materials
2010 Biomed Tech, Band: 55, Ergänzungsband: 1
Rubehn B, Lewis C, Dries P, Stieglitz T
Flexible Shaft Electrodes for Transdural Implantation and Chronic Recording
2010 Proceedings 10th Vienna Workshop on Functional Electrical Stimulation and 15th Annual International Conference of the Int. Functional Electrical Stimulation Society. Vienna , Seiten: 43 - 45
Boretius T, Schuettler M, Stieglitz T
On the Stability of PEDOT as Coating Material for Active Neural Implants
2010 Proceedings 10th Vienna Workshop on Functional Electrical Stimulation and 15th Annual International Conference of the Int. Functional Electrical Stimulation Society. Vienna , Seiten: 28 - 31

2008

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Eickenscheidt Max, Zeck Günther, Fromherz Peter
Capacitive stimulation of rabbit ganglion cells in epiretinal configuration
2008 Int. Meeting on Substrate-Integrated Microelectrodes, Reutlingen, Germany , Band: 6, Seite: 161

1999

nach oben zur Jahresübersicht

Stieglitz T, Beutel H, Keller R, Schuettler M, Meyer J
Flexible, Polyimide-Based Neural Interfaces
1999 MicroNeuro '99, Granada, Spain MicroNeuro 99, Seiten: 112 - 119
Stieglitz T, Meyer J
Flexible, Multikanal-Mikroelektroden für die Neuroprothetik
1999 AUTOMED99, 2. Workshop Automatisierungstechnische Verfahren für die Medizin, Darmstadt Fortschritt-Berichte VDI, Leonhardt, S. et al., Band: 183, Seiten: 67 - 68

1998

nach oben zur Jahresübersicht

Thielecke H, Stieglitz T, Beutel H, Matthies T, Meyer J
A Novel Cell-Positioning Technique for Extracellular Recording and Impedance Measurement on Single Cells Using Planar Electrode Substrates
1998 Hong Kong, China Proc 20th IEEE-EMBS Conf., Band: 6, Seiten: 2872 - 2875
Scholz O, Marin D, Parramon J, Stieglitz T, Eberle W, Meyer J
Evaluation and Examination of Wireless Communications for Neural Prostheses
1998 Proc 6th International Workshop on FES, Seiten: 77 - 80
Stieglitz T, Meyer J
Flexible Microelectrode Arrays for Recording and Stimulation in the Peripheral and Central Nervous System
1998 Zentralblatt für Neurochirurgie, Band: 59, Ergänzungsband: 1, Seiten: 136 - 137
Beutel H, Stieglitz T, Meyer J
Microflex: A New Technique for Hybrid Integration of Microsystems
1998 Heidelberg, Germany 11th IEEE-MEMS Workshop, Seiten: 306 - 311
Stieglitz T, Beutel H, Blau C, Meyer J
Micromachined Devices for Interfacing Neurons
1998 Proceedings of SPIE, Wuttig, Band: 3324, Seiten: 174 - 185
Stieglitz T, Schuettler M, Keller R, Meyer J
Shielding of Flexible Micro-Electrode Interconnects for Suppression of Artifacts in Neural Prostheses
1998 20th IEEE-EMBS Conf., Seiten: 2574 - 2577
Beutel H, Stieglitz T, Meyer J
Versatile 'Microflex'-based Interconnection Technique
1998 Proceedings of SPIE, Varadan, McWorther, Singer, Vellekoop, Band: 3328, Seiten: 174 - 182

1997

nach oben zur Jahresübersicht

Stieglitz T, Matal T, Staemmler M
A Modular Multichannel Stimulator for Arbitrary Shaped Pulses for Experimental and Clinical Use in FES
1997 Chicago, USA 19th IEEE-EMBS Conf., Seiten: 1777 - 1780
Stieglitz T, Beutel H, Keller R, Blau C, Meyer J
Development of Flexible Stimulation Devices for a Retina Implant System
1997 Chicago, USA 19th IEEE-EMBS Conf., Band: 5, Seiten: 2307 - 2310
Stieglitz T, Matal T, Staemmler M
Ein modularer Multikanal Stimulator zur Erzeugung von Reizpulsen beliebiger Wellenform für den Experimentellen und Klinischen Einsatz
1997 Biomed Tech, Band: 42, Ergänzungsband: 2, Seiten: 443 - 444
Stieglitz T, Beutel H, Blau C, Meyer J
Flexible Multikanal-Mikroelektroden mit integrierten Zuleitungen zum Einsatz in der Mikroprothetik
1997 Biomed Tech, Band: 42, Ergänzungsband: 2, Seiten: 449 - 450
Stieglitz T, Beutel H, Keller R, Blau C, Meyer J
Konzeption und Entwicklung von flexiblen Stimulatorstrukturen innerhalb eines Retina Implantat Systems
1997 Biomed Tech, Band: 42, Ergänzungsband: 2, Seiten: 458 - 459
Stieglitz T, Seif C, Schumacher S, Bross S, Juenemann K, Meyer J
Selective Activation of the Urinary Bladder with Quasi-trapezoidal Pulses in Sacral Anterior Root Stimulation in the Dog
1997 Chicago, USA 19th IEEE-EMBS Conf., Band: 5, Seiten: 1807 - 1809
Stieglitz T, Seif C, Bross S, Schumacher S, Jünemann K, Meyer J
Selektive Aktivierung der Blase mittels Quasi-trapezoidaler Pulse bei der Sakralen Vorderwurzelstimulation beim Hund
1997 Biomed Tech, Band: 42, Ergänzungsband: 2, Seiten: 492 - 493

1996

nach oben zur Jahresübersicht

Stieglitz T, Blau C, Meyer J
Flexible, Light-weighted Electrodes to Contact the Peripheral Nervous System
1996 Amsterdam, Netherlands 18th IEEE-EMBS Conf., Seiten: 363 - 364
Stieglitz T, Navarro X, Calvet S, Blau C, Meyer J
Interfacing Regenerating Peripheral Nerves with a Micromachined Polyimide Sieve Electrode
1996 Amsterdam, Netherlands 18th IEEE-EMBS Conf., Seiten: 365 - 366

1995

nach oben zur Jahresübersicht

Stieglitz T, Meyer J
Characterization of Flexible Electrodes with Integrated Cables for Recording and Stimulation of Peripheral Nerves
1995 Vienna, Austria Proc 5th International Workshop on FES, Seiten: 145 - 148

1993

nach oben zur Jahresübersicht

Nützel A, Breisacher D, Stieglitz T, Vossius G
Neuronale Netze zur Klassifizierung von EMG-Signalen bei Spastik
1993 Biomed Tech, Band: 38, Ergänzungsband: 1, Seiten: 465 - 466

Sonstige Publikationen

Jahre: 2018 | 2016 | 2015 | 2014 | 2010

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2018

nach oben zur Jahresübersicht

Stieglitz T, von Metzen R, Stett A
Bioelektronische Medizin-Eine Einführung in eine neue Disziplin.
VDE Health Expertenbeiträge, Band: 1, Seiten: 1 - 4, 2018

2016

nach oben zur Jahresübersicht

Stieglitz T
Wenn Technik den Nerv trifft. Aussteller/Stand auf den "Highlights der Physik", 27.09.- 01.10.2016, Ulm
, 2016

2015

nach oben zur Jahresübersicht

Stieglitz T
Neuroimplantate
Spektrum der Wissenschaft-Spezial, Physik-Mathematik-Technik, Seiten: 6 - 13, 2015
Stieglitz, T, Schuettler, M, Plachta, D.T.T
Neuroprothetik heute und morgen
Orthopaedie Technik, Nummer: 6/15, Seiten: 32 - 37, 2015

2014

nach oben zur Jahresübersicht

Bertotti Gabriel, Velychko Dmytro, Dodel Norman, Keil Stefan, Wolansky Dirk, Tillak Bernd, Schreiter Matthias, Grall Andreas, Jesinger Peter, Rohler Sebastian
A CMOS-based sensor array for in-vitro neural tissue interfacing with 4225 recording sites and 1024 stimulation sites
IEEE, Seiten: 304 - 307, 2014

2010

nach oben zur Jahresübersicht

Klar R, Stieglitz T
Biomedizinische Technik, Chancen und Risiken
Bundesgesundheitsbla, Band: 53, Nummer: 8, Seiten: 757 - 758, 2010

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