Home Development of a bending test procedure for the characterization of flexible ECoG electrode arrays
Article Open Access

Development of a bending test procedure for the characterization of flexible ECoG electrode arrays

  • Fabian Kohler EMAIL logo , Rebecca Michiels , Martin Schuettler and Thomas Stieglitz
Published/Copyright: September 12, 2015
Download Article (PDF)
Become an author with De Gruyter Brill
Author Information Explore this Subject
Current Directions in Biomedical Engineering
From the journal Current Directions in Biomedical Engineering Volume 1 Issue 1

Abstract

An automatized mechanical test has been developed to characterize flexible ECoG and grid electrode arrays under cyclic bending load. Electrodes with different test structures were designed and the bending cycle dependant failure rate was found to follow a Weibull distribution. A corresponding failure mode analysis revealed a characteristic lifetime of more than 25000 bending cycles for some designs. However, design parameters as e.g. a smaller track width reduced this lifetime by a factor of two. In comparison to a similar BMI grid electrode array which was implanted for several months in an animal, failure patterns were comparable to those simulated with the bending test.

Keywords: ECoG electrode; bending stability; reliability

1 Introduction

A promising approach towards the creation of highly selective brain-machine-interfaces (BMI) is the utilization of flexible electrocorticography (ECoG) electrode arrays based on a polymer-metal-polymer-sandwich system [1]. Unfortunately, these electrodes are very sensitive to mechanical loads and show failure due to breaking of the delicate metal structures. It has proven difficult to reach the desired flexibility of the electrode arrays without compromising the mechanical stability. In the past, mostly tensile loads were investigated for these kind of electrodes [2]. To evaluate the stability under bending loads and to identify the unique failure mechanisms of such structures, an individually adaptable bending test procedure has to be developed which keeps tensile influences as small as possible.

2 Methods

2.1 Bending test principle

The test apparatus was designed according to the following simple bending principle. The flexible electrode arrays were mounted between two perpendicular plates and thereby forced to bend within the interjacent distance (Fig. 1). By changing the latter, the bending radius R could be varied and adapted to the test conditions. Enabling vertical movement for one of the plates allowed shifting of the bending’s vertex continuously over the electrode array. By choosing large movement distances, almost the whole array could be tested. As soon as the turning point was reached, the plate travelled back and the next cycle was started. These cyclic bending loads should simulate repetitive deformation of the electrode. The integrity of the electrode’s individual tracks was monitored via four wire resistance measurement. An important measure to describe the bending stability is the bending (or flexural) stiffness which is defined by a relationship between bending moment Mb, bending radius R, Young’s modulus E and moment of inertia I (Fig. 1 – b) and eq. 1).

(1)EI=Mb/R

For these type of sandwiched polymer-metal electrodes, the bending stiffness is dominated by the metal layer which also defines the neutral plane within the compound. It is important to keep the asymmetric layer structure in mind when choosing a suitable bending radius.

2.2 Test apparatus

To enable an automatized bending and measurement procedure, a computer-controlled test setup was built. The following section is split in two sub-sections – the mechanical assembly and electronic control with data recording.

2.2.1 Mechanical assembly

According to the test principle described in section 2.1, the aim was to build two parallel planes where one had to be moveable in vertical direction. For that purpose, a linear guide unit with a gear drive belt (ZLW-0630, IGUS GmbH, Cologne, Germany) was vertically mounted on a base made of polymethylmethacrylate (PMMA). The aluminium guiding rail was equipped with a spacer which allowed fixation of the movable plate. The static counter plate was mounted perpendicular to the base on a horizontal slide (DryLin-T, IGUS), which allowed adjustment of the distance between the two plates and hence of the bending radius R for the test. Two different types of electrode chucks were developed, which could be stacked on the top end of each plate. For large electrode arrays with lateral dimensions exceeding 80 mm, a vacuum chuck was used. It possessed 17 holes, connectable to a vacuum supply, to reliably attach one side of the array. For smaller electrodes, such as the BMI ECoG electrode (cf. section 2.4), the second chuck type with its mechanical clamp was used. For the sake of completeness, both types are illustrated in Fig. 2 which depicts the mechanical parts of the assembly. To define the maximum test distance of the moveable plate, turning points had to be defined. For that purpose, sub-miniature switches (AH1FS, Panasonic, Hamburg, Germany) were mounted in custom sensor fixtures which could be placed in the linear unit’s side notch. As soon as the spacer of the vertical slide hit the switch, direction of movement was changed. For accurate placement of the sensor fixtures and a defined movement distance, a scale was attached to the back of the linear unit. According to the manufacturer, the linear unit needs a driving torque of 0.25 Nm. Two different engines (Type RB35, Modelcraft, Blaine, USA) were utilized to enable different movement speeds. Their main properties are summarized in Table 1.

Figure 1 Functional principle of the bending test with simultaneous four-wire resistance monitoring. a) Sketch of a non-bended electrode segment (length l), b) shows a segment under bending load incl. stress (σ) development and bending moment Mb. R is the bending radius, dϕ the bending angle.
Figure 1

Functional principle of the bending test with simultaneous four-wire resistance monitoring. a) Sketch of a non-bended electrode segment (length l), b) shows a segment under bending load incl. stress (σ) development and bending moment Mb. R is the bending radius, dϕ the bending angle.

Figure 2 Mechanical assembly of the bending test apparatus.
Figure 2

Mechanical assembly of the bending test apparatus.

Table 1

Properties of two electro motors which were used for driving the linear unit.

Motor 1Motor 2
Driving torque0.6 Nm0.3 Nm
Transmission1:6001:50
Speed10 rpm120 rpm

2.2.2 Electronic control

Control of the electro motors as well as communication with a computer to initiate electrical measurement of the electrode tracks was achieved with a customized electronic circuit, subsequently referred to as motor control. A LabView (National Instruments, Austin, USA) program was written to enable automatic control of the up and down movement of the tester as well as data recording of the electrode track resistance development. After a defined amount of bending cycles, which could be set in the software, the movement was stopped and the electrode array was characterized by means of four-wire measurement. A multimeter (34401A, Agilent) performed the electrical measurement and a custom multiplexer (MUX) was used to toggle between the electrode channels, i.e. different tracks. A data acquisition microcontroller – DAQ (USB 6008, National Instruments) was utilized to control the MUX and the motor control circuit. A simplified block diagram to illustrate signal and control pathways is given in Fig. 3.

Figure 3 Block diagram of the electronic control and data acquisition.
Figure 3

Block diagram of the electronic control and data acquisition.

2.3 Design of test electrodes

To evaluate the effect of different track and contact geometries on the stability under bending load, test electrode arrays were designed and manufactured according to a well-established laser-based process. Details are described elsewhere [3]. The conductive material for electrode tracks and contacts was MP35N (thickness 25 µm) embedded in medical grade silicone rubber (MED1000, Nusil, Carpinteria, USA). Four different test types were placed on the 80 x 80 mm2 electrode array (Fig. 4 –A, B, C, D). Each in two configurations, straight (1) and 180°-turn (2). For the test design below, the track width (70 µm) and contact size (1.1 mm) was scaled up by a factor of 1.5 (type A & C) and 2.0 (B & D) compared to the BMI ECoG described in earlier publications [4].

Electrode tracks were electrically connected to the multiplexer by means of MP35N wires (ř = 75 µm) which were resistance-welded to the bared track ends at the contact openings of the test array (Fig. 4 - top). The welds were stabilized and protected with a droplet of silicone rubber.

Three electrodes with structures as shown in Fig. 4 were tested to a limit of 35 000 bending cycles at a bending radius R = 6 mm. This radius originated from a worst case bending scenario during implantation. Motor 1 was utilized for this experiment (Table 1). Tracks which were still unharmed after passing this threshold were excluded from the data analysis and investigated separately. Within the first 100 cycles, the resistance was recorded every ten bendings. After that, an interval of 100 cycles was chosen for further recordings. A two-parameter Weibull failure mode analysis was performed for the dataset, to determine the characteristic lifetime T, where 63.2 % of the individual design types had failed. Details concerning the mathematical background can be found in [5]. Furthermore the type of failure was visually determined.

Figure 4 Test electrode layout
Figure 4

Test electrode layout

2.4 BMI ECoG electrode array

A significantly smaller ECoG electrode array of a similar design as used for in vivo experiments [1] was characterized with the bending tester, too. Due to its lateral dimensions (ca. 20 x 36 mm2, exact dimension and layout can be found in [4]) it had to be mounted onto an overhead projector foil as carrier before testing. The bending radius was again set to 6 mm. The tracks’ integrity was measured after 10, 100, 1000 and 2000 cycles. The failure pattern was optically compared to the array which was implanted for 15 months in an animal (sheep) and had been potentially exposed to rough handling during surgery.

3 Results

3.1 Test electrodes

In a first comparison of all tracks which had failed within the 35000 cycles, the Weibull distribution seemed to be an adequate fit for the analysis. The measurements did not reveal any difference between straight and 180°-turn tracks, hence both designs were summarized for the subsequent analyses. The characteristic lifetime T for wide tracks (scale factor 2) could be more than doubled to >25000 cycles compared to smaller tracks (scale factor 1.5). Furthermore, the Weibull shape factor β was increased from 1.21 (type A&C), which hypothesizes a random failure mode, to 2.28 (type B&D), indicating a wear-related failure due to the high amount of bending cycles (Fig. 5). A comparison of the individual designs (Table 2) showed a tendency for meander shaped small tracks (type A) to fail early due to e.g. manufacturing issues (β<1). Regarding the characteristic lifetime, the analysis did not result in a significant difference between meander and straight track design. The significantly increased shape factor for wide tracks without meander (type B) indicated a Gaussian rather than a Weibull distributed failure probability function.

Figure 5 Weibull plot of different track widths and their failure probability as a function of bending cycles.
Figure 5

Weibull plot of different track widths and their failure probability as a function of bending cycles.

A high standard error for and T could be explained by the sample size for the individual designs under test (N=8-12). The most prominent failure throughout all designs was breakage at the transition, track to contact pad (Fig. 6). It is important to mention that multiple failures of a single track were included in this evaluation, e.g. each contact pad could break at the top and bottom transition. The sample size in Fig. 6 is hence a measure for all conceivable failure spots per design type on all three arrays tested.

Table 2

Weibull parameters for different electrode design types.

Test typeShape factor βChar.LifetimeTincycles
A0.85 ±0.2612477 ±5758
C1.45 ±0.4512489 ±2920
B3.68 ±1.0924928 ±2686
D1.82 ±0.4925009 ±4537
Figure 6 Summary of different failure modes per design type.
Figure 6

Summary of different failure modes per design type.

3.2 BMI grid electrode array

The BMI grid array possessed very delicate structures (width = 70 µm) which were significantly more sensitive to mechanical loads compared to the test tracks in section 3.1. All but seven tracks were damaged after 2000 bending cycles (79 % failure rate). In 22 cases, the transition, track to pad failed (Fig. 7 - right), which was again the most apparent weak spot. In comparison to the similar array which was utilized in vivo for 15 months [4] and obviously deformed (Fig. 7 - center) the track - pad transition failed in seven cases. Even though the kind of bending might have been different and less frequent during handling, surgery etc., the failure mode was comparable (Fig. 7 – left).

Figure 7 Visual comparison of a failed electrode track due to the bending test and after in vivo experiment with subsequent explantation. Arrows indicate track breakage.
Figure 7

Visual comparison of a failed electrode track due to the bending test and after in vivo experiment with subsequent explantation. Arrows indicate track breakage.

4 Conclusion

The introduced bending test procedure for flexible electrode arrays allows to reliably predict the stability of different electrode track geometries. Failure modes were also comparable to previous in vivo experiments. Based on these findings, design rules can be set to create electrodes of superior reliability for future cortical implants.

Author's Statement

  1. Conflict of interest: MS is CTO and FK and TS are consultants of Cortec GmbH. Material and Methods: Informed consent: Informed consent is not applicable. Ethical approval: The research related to animals use has been complied with all the relevant national regulations and institutional policies for the care and use of animals.

References

[1] Gierthmuehlen, M.; Wang, X.; Gkogkidis, A.; et al., “Mapping of sheep sensory cortex with a novel microelectrocorticography grid”, The J. comp. neurol., 2014; 522 (16): 3590–360810.1002/cne.23631Search in Google Scholar PubMed

[2] Schuettler, M.; Pfau, D.; Ordonez, J. S.; et al., “Stretchable tracks for laser-machined neural electrode arrays”, Proc. IEEE EMBC, 2009: 1612–161510.1109/IEMBS.2009.5333224Search in Google Scholar PubMed

[3] Schuettler, M.; Stiess, S.; King, B. V.; Suaning, G. J., “Fabrication of implantable microelectrode arrays by laser cutting of silicone rubber and platinum foil”, JNE, 2005; 2 (1): S121-810.1088/1741-2560/2/1/013Search in Google Scholar PubMed

[4] Kohler, F.; Stieglitz, T.; Schuettler, M., “Morphological and electrochemical properties of an explanted PtIr electrode array after 15 months in vivo”, Proc. IEEE EMBC, 2014, 418–42110.1109/EMBC.2014.6943617Search in Google Scholar PubMed

[5] McCool, J., “Using the Weibull distribution”, John Wiley & Sons, Hoboken, N.J., 201210.1002/9781118351994Search in Google Scholar

Published Online: 2015-9-12
Published in Print: 2015-9-1

© 2015 by Walter de Gruyter GmbH, Berlin/Boston

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Articles in the same Issue

  1. Research Article
  2. Development and characterization of superparamagnetic coatings
  3. Research Article
  4. The development of an experimental setup to measure acousto-electric interaction signal
  5. Research Article
  6. Stability analysis of ferrofluids
  7. Research Article
  8. Investigation of endothelial growth using a sensors-integrated microfluidic system to simulate physiological barriers
  9. Research Article
  10. Energy harvesting for active implants: powering a ruminal pH-monitoring system
  11. Research Article
  12. New type of fluxgate magnetometer for the heart’s magnetic fields detection
  13. Research Article
  14. Field mapping of ballistic pressure pulse sources
  15. Research Article
  16. Development of a new homecare sleep monitor using body sounds and motion tracking
  17. Research Article
  18. Noise properties of textile, capacitive EEG electrodes
  19. Research Article
  20. Detecting phase singularities and rotor center trajectories based on the Hilbert transform of intraatrial electrograms in an atrial voxel model
  21. Research Article
  22. Spike sorting: the overlapping spikes challenge
  23. Research Article
  24. Separating the effect of respiration from the heart rate variability for cases of constant harmonic breathing
  25. Research Article
  26. Locating regions of arrhythmogenic substrate by analyzing the duration of triggered atrial activities
  27. Research Article
  28. Combining different ECG derived respiration tracking methods to create an optimal reconstruction of the breathing pattern
  29. Research Article
  30. Atrial and ventricular signal averaging electrocardiography in pacemaker and cardiac resynchronization therapy
  31. Research Article
  32. Estimation of a respiratory signal from a single-lead ECG using the 4th order central moments
  33. Research Article
  34. Compressed sensing of multi-lead ECG signals by compressive multiplexing
  35. Research Article
  36. Heart rate monitoring in ultra-high-field MRI using frequency information obtained from video signals of the human skin compared to electrocardiography and pulse oximetry
  37. Research Article
  38. Synchronization in wireless biomedical-sensor networks with Bluetooth Low Energy
  39. Research Article
  40. Automated classification of stages of anaesthesia by populations of evolutionary optimized fuzzy rules
  41. Research Article
  42. Effects of sampling rate on automated fatigue recognition in surface EMG signals
  43. Research Article
  44. Closed-loop transcranial alternating current stimulation of slow oscillations
  45. Research Article
  46. Cardiac index in atrio- and interventricular delay optimized cardiac resynchronization therapy and cardiac contractility modulation
  47. Research Article
  48. The role of expert evaluation for microsleep detection
  49. Research Article
  50. The impact of baseline wander removal techniques on the ST segment in simulated ischemic 12-lead ECGs
  51. Research Article
  52. Metal artifact reduction by projection replacements and non-local prior image integration
  53. Research Article
  54. A novel coaxial nozzle for in-process adjustment of electrospun scaffolds’ fiber diameter
  55. Research Article
  56. Processing of membranes for oxygenation using the Bellhouse-effect
  57. Research Article
  58. Inkjet printing of viable human dental follicle stem cells
  59. Research Article
  60. The use of an icebindingprotein out of the snowflea Hypogastrura harveyi as a cryoprotectant in the cryopreservation of mesenchymal stem cells
  61. Research Article
  62. New NIR spectroscopy based method to determine ischemia in vivo in liver – a first study on rats
  63. Research Article
  64. QRS and QT ventricular conduction times and permanent pacemaker therapy after transcatheter aortic valve implantation
  65. Research Article
  66. Adopting oculopressure tonometry as a transient in vivo rabbit glaucoma model
  67. Research Article
  68. Next-generation vision testing: the quick CSF
  69. Research Article
  70. Improving tactile sensation in laparoscopic surgery by overcoming size restrictions
  71. Research Article
  72. Design and control of a 3-DOF hydraulic driven surgical instrument
  73. Research Article
  74. Evaluation of endourological tools to improve the diagnosis and therapy of ureteral tumors – from model development to clinical application
  75. Research Article
  76. Frequency based assessment of surgical activities
  77. Research Article
  78. “Hands free for intervention”, a new approach for transoral endoscopic surgery
  79. Research Article
  80. Pseudo-haptic feedback in medical teleoperation
  81. Research Article
  82. Feasibility of interactive gesture control of a robotic microscope
  83. Research Article
  84. Towards structuring contextual information for workflow-driven surgical assistance functionalities
  85. Research Article
  86. Towards a framework for standardized semantic workflow modeling and management in the surgical domain
  87. Research Article
  88. Closed-loop approach for situation awareness of medical devices and operating room infrastructure
  89. Research Article
  90. Kinect based physiotherapy system for home use
  91. Research Article
  92. Evaluating the microsoft kinect skeleton joint tracking as a tool for home-based physiotherapy
  93. Research Article
  94. Integrating multimodal information for intraoperative assistance in neurosurgery
  95. Research Article
  96. Respiratory motion tracking using Microsoft’s Kinect v2 camera
  97. Research Article
  98. Using smart glasses for ultrasound diagnostics
  99. Research Article
  100. Measurement of needle susceptibility artifacts in magnetic resonance images
  101. Research Article
  102. Dimensionality reduction of medical image descriptors for multimodal image registration
  103. Research Article
  104. Experimental evaluation of different weighting schemes in magnetic particle imaging reconstruction
  105. Research Article
  106. Evaluation of CT capability for the detection of thin bone structures
  107. Research Article
  108. Towards contactless optical coherence elastography with acoustic tissue excitation
  109. Research Article
  110. Development and implementation of algorithms for automatic and robust measurement of the 2D:4D digit ratio using image data
  111. Research Article
  112. Automated high-throughput analysis of B cell spreading on immobilized antibodies with whole slide imaging
  113. Research Article
  114. Tissue segmentation from head MRI: a ground truth validation for feature-enhanced tracking
  115. Research Article
  116. Video tracking of swimming rodents on a reflective water surface
  117. Research Article
  118. MR imaging of model drug distribution in simulated vitreous
  119. Research Article
  120. Studying the extracellular contribution to the double wave vector diffusion-weighted signal
  121. Research Article
  122. Artifacts in field free line magnetic particle imaging in the presence of inhomogeneous and nonlinear magnetic fields
  123. Research Article
  124. Introducing a frequency-tunable magnetic particle spectrometer
  125. Research Article
  126. Imaging of aortic valve dynamics in 4D OCT
  127. Research Article
  128. Intravascular optical coherence tomography (OCT) as an additional tool for the assessment of stent structures
  129. Research Article
  130. Simple concept for a wide-field lensless digital holographic microscope using a laser diode
  131. Research Article
  132. Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment – a feasibility study
  133. Research Article
  134. Respiratory surface motion measurement by Microsoft Kinect
  135. Research Article
  136. Improving image quality in EIT imaging by measurement of thorax excursion
  137. Research Article
  138. A clustering based dual model framework for EIT imaging: first experimental results
  139. Research Article
  140. Three-dimensional anisotropic regularization for limited angle tomography
  141. Research Article
  142. GPU-based real-time generation of large ultrasound volumes from freehand 3D sweeps
  143. Research Article
  144. Experimental computer tomograph
  145. Research Article
  146. US-tracked steered FUS in a respiratory ex vivo ovine liver phantom
  147. Research Article
  148. Contribution of brownian rotation and particle assembly polarisation to the particle response in magnetic particle spectrometry
  149. Research Article
  150. Preliminary investigations of magnetic modulated nanoparticles for microwave breast cancer detection
  151. Research Article
  152. Construction of a device for magnetic separation of superparamagnetic iron oxide nanoparticles
  153. Research Article
  154. An IHE-conform telecooperation platform supporting the treatment of dementia patients
  155. Research Article
  156. Automated respiratory therapy system based on the ARDSNet protocol with systemic perfusion control
  157. Research Article
  158. Identification of surgical instruments using UHF-RFID technology
  159. Research Article
  160. A generic concept for the development of model-guided clinical decision support systems
  161. Research Article
  162. Evaluation of local alterations in femoral bone mineral density measured via quantitative CT
  163. Research Article
  164. Creating 3D gelatin phantoms for experimental evaluation in biomedicine
  165. Research Article
  166. Influence of short-term fixation with mixed formalin or ethanol solution on the mechanical properties of human cortical bone
  167. Research Article
  168. Analysis of the release kinetics of surface-bound proteins via laser-induced fluorescence
  169. Research Article
  170. Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine
  171. Research Article
  172. Wireless medical sensors – context, robustness and safety
  173. Research Article
  174. Sequences for real-time magnetic particle imaging
  175. Research Article
  176. Speckle-based off-axis holographic detection for non-contact photoacoustic tomography
  177. Research Article
  178. A machine learning approach for planning valve-sparing aortic root reconstruction
  179. Research Article
  180. An in-ear pulse wave velocity measurement system using heart sounds as time reference
  181. Research Article
  182. Measuring different oxygenation levels in a blood perfusion model simulating the human head using NIRS
  183. Research Article
  184. Multisegmental fusion of the lumbar spine a curse or a blessing?
  185. Research Article
  186. Numerical analysis of the biomechanical complications accompanying the total hip replacement with NANOS-Prosthetic: bone remodelling and prosthesis migration
  187. Research Article
  188. A muscle model for hybrid muscle activation
  189. Research Article
  190. Mathematical, numerical and in-vitro investigation of cooling performance of an intra-carotid catheter for selective brain hypothermia
  191. Research Article
  192. An ideally parameterized unscented Kalman filter for the inverse problem of electrocardiography
  193. Research Article
  194. Interactive visualization of cardiac anatomy and atrial excitation for medical diagnosis and research
  195. Research Article
  196. Virtualizing clinical cases of atrial flutter in a fast marching simulation including conduction velocity and ablation scars
  197. Research Article
  198. Mesh structure-independent modeling of patient-specific atrial fiber orientation
  199. Research Article
  200. Accelerating mono-domain cardiac electrophysiology simulations using OpenCL
  201. Research Article
  202. Understanding the cellular mode of action of vernakalant using a computational model: answers and new questions
  203. Research Article
  204. A java based simulator with user interface to simulate ventilated patients
  205. Research Article
  206. Evaluation of an algorithm to choose between competing models of respiratory mechanics
  207. Research Article
  208. Numerical simulation of low-pulsation gerotor pumps for use in the pharmaceutical industry and in biomedicine
  209. Research Article
  210. Numerical and experimental flow analysis in centifluidic systems for rapid allergy screening tests
  211. Research Article
  212. Biomechanical parameter determination of scaffold-free cartilage constructs (SFCCs) with the hyperelastic material models Yeoh, Ogden and Demiray
  213. Research Article
  214. FPGA controlled artificial vascular system
  215. Research Article
  216. Simulation based investigation of source-detector configurations for non-invasive fetal pulse oximetry
  217. Research Article
  218. Test setup for characterizing the efficacy of embolic protection devices
  219. Research Article
  220. Impact of electrode geometry on force generation during functional electrical stimulation
  221. Research Article
  222. 3D-based visual physical activity assessment of children
  223. Research Article
  224. Realtime assessment of foot orientation by Accelerometers and Gyroscopes
  225. Research Article
  226. Image based reconstruction for cystoscopy
  227. Research Article
  228. Image guided surgery innovation with graduate students - a new lecture format
  229. Research Article
  230. Multichannel FES parameterization for controlling foot motion in paretic gait
  231. Research Article
  232. Smartphone supported upper limb prosthesis
  233. Research Article
  234. Use of quantitative tremor evaluation to enhance target selection during deep brain stimulation surgery for essential tremor
  235. Research Article
  236. Evaluation of adhesion promoters for Parylene C on gold metallization
  237. Research Article
  238. The influence of metallic ions from CoCr28Mo6 on the osteogenic differentiation and cytokine release of human osteoblasts
  239. Research Article
  240. Increasing the visibility of thin NITINOL vascular implants
  241. Research Article
  242. Possible reasons for early artificial bone failure in biomechanical tests of ankle arthrodesis systems
  243. Research Article
  244. Development of a bending test procedure for the characterization of flexible ECoG electrode arrays
  245. Research Article
  246. Tubular manipulators: a new concept for intracochlear positioning of an auditory prosthesis
  247. Research Article
  248. Investigation of the dynamic diameter deformation of vascular stents during fatigue testing with radial loading
  249. Research Article
  250. Electrospun vascular grafts with anti-kinking properties
  251. Research Article
  252. Integration of temperature sensors in polyimide-based thin-film electrode arrays
  253. Research Article
  254. Use cases and usability challenges for head-mounted displays in healthcare
  255. Research Article
  256. Device- and service profiles for integrated or systems based on open standards
  257. Research Article
  258. Risk management for medical devices in research projects
  259. Research Article
  260. Simulation of varying femoral attachment sites of medial patellofemoral ligament using a musculoskeletal multi-body model
  261. Research Article
  262. Does enhancing consciousness for strategic planning processes support the effectiveness of problem-based learning concepts in biomedical education?
  263. Research Article
  264. SPIO processing in macrophages for MPI: The breast cancer MPI-SNLB-concept
  265. Research Article
  266. Numerical simulations of airflow in the human pharynx of OSAHS patients
https://doi.org/10.1515/cdbme-2015-0122
Keywords for this article
ECoG electrode; bending stability; reliability
Creative Commons
BY-NC-ND 3.0

Articles in the same Issue

  1. Research Article
  2. Development and characterization of superparamagnetic coatings
  3. Research Article
  4. The development of an experimental setup to measure acousto-electric interaction signal
  5. Research Article
  6. Stability analysis of ferrofluids
  7. Research Article
  8. Investigation of endothelial growth using a sensors-integrated microfluidic system to simulate physiological barriers
  9. Research Article
  10. Energy harvesting for active implants: powering a ruminal pH-monitoring system
  11. Research Article
  12. New type of fluxgate magnetometer for the heart’s magnetic fields detection
  13. Research Article
  14. Field mapping of ballistic pressure pulse sources
  15. Research Article
  16. Development of a new homecare sleep monitor using body sounds and motion tracking
  17. Research Article
  18. Noise properties of textile, capacitive EEG electrodes
  19. Research Article
  20. Detecting phase singularities and rotor center trajectories based on the Hilbert transform of intraatrial electrograms in an atrial voxel model
  21. Research Article
  22. Spike sorting: the overlapping spikes challenge
  23. Research Article
  24. Separating the effect of respiration from the heart rate variability for cases of constant harmonic breathing
  25. Research Article
  26. Locating regions of arrhythmogenic substrate by analyzing the duration of triggered atrial activities
  27. Research Article
  28. Combining different ECG derived respiration tracking methods to create an optimal reconstruction of the breathing pattern
  29. Research Article
  30. Atrial and ventricular signal averaging electrocardiography in pacemaker and cardiac resynchronization therapy
  31. Research Article
  32. Estimation of a respiratory signal from a single-lead ECG using the 4th order central moments
  33. Research Article
  34. Compressed sensing of multi-lead ECG signals by compressive multiplexing
  35. Research Article
  36. Heart rate monitoring in ultra-high-field MRI using frequency information obtained from video signals of the human skin compared to electrocardiography and pulse oximetry
  37. Research Article
  38. Synchronization in wireless biomedical-sensor networks with Bluetooth Low Energy
  39. Research Article
  40. Automated classification of stages of anaesthesia by populations of evolutionary optimized fuzzy rules
  41. Research Article
  42. Effects of sampling rate on automated fatigue recognition in surface EMG signals
  43. Research Article
  44. Closed-loop transcranial alternating current stimulation of slow oscillations
  45. Research Article
  46. Cardiac index in atrio- and interventricular delay optimized cardiac resynchronization therapy and cardiac contractility modulation
  47. Research Article
  48. The role of expert evaluation for microsleep detection
  49. Research Article
  50. The impact of baseline wander removal techniques on the ST segment in simulated ischemic 12-lead ECGs
  51. Research Article
  52. Metal artifact reduction by projection replacements and non-local prior image integration
  53. Research Article
  54. A novel coaxial nozzle for in-process adjustment of electrospun scaffolds’ fiber diameter
  55. Research Article
  56. Processing of membranes for oxygenation using the Bellhouse-effect
  57. Research Article
  58. Inkjet printing of viable human dental follicle stem cells
  59. Research Article
  60. The use of an icebindingprotein out of the snowflea Hypogastrura harveyi as a cryoprotectant in the cryopreservation of mesenchymal stem cells
  61. Research Article
  62. New NIR spectroscopy based method to determine ischemia in vivo in liver – a first study on rats
  63. Research Article
  64. QRS and QT ventricular conduction times and permanent pacemaker therapy after transcatheter aortic valve implantation
  65. Research Article
  66. Adopting oculopressure tonometry as a transient in vivo rabbit glaucoma model
  67. Research Article
  68. Next-generation vision testing: the quick CSF
  69. Research Article
  70. Improving tactile sensation in laparoscopic surgery by overcoming size restrictions
  71. Research Article
  72. Design and control of a 3-DOF hydraulic driven surgical instrument
  73. Research Article
  74. Evaluation of endourological tools to improve the diagnosis and therapy of ureteral tumors – from model development to clinical application
  75. Research Article
  76. Frequency based assessment of surgical activities
  77. Research Article
  78. “Hands free for intervention”, a new approach for transoral endoscopic surgery
  79. Research Article
  80. Pseudo-haptic feedback in medical teleoperation
  81. Research Article
  82. Feasibility of interactive gesture control of a robotic microscope
  83. Research Article
  84. Towards structuring contextual information for workflow-driven surgical assistance functionalities
  85. Research Article
  86. Towards a framework for standardized semantic workflow modeling and management in the surgical domain
  87. Research Article
  88. Closed-loop approach for situation awareness of medical devices and operating room infrastructure
  89. Research Article
  90. Kinect based physiotherapy system for home use
  91. Research Article
  92. Evaluating the microsoft kinect skeleton joint tracking as a tool for home-based physiotherapy
  93. Research Article
  94. Integrating multimodal information for intraoperative assistance in neurosurgery
  95. Research Article
  96. Respiratory motion tracking using Microsoft’s Kinect v2 camera
  97. Research Article
  98. Using smart glasses for ultrasound diagnostics
  99. Research Article
  100. Measurement of needle susceptibility artifacts in magnetic resonance images
  101. Research Article
  102. Dimensionality reduction of medical image descriptors for multimodal image registration
  103. Research Article
  104. Experimental evaluation of different weighting schemes in magnetic particle imaging reconstruction
  105. Research Article
  106. Evaluation of CT capability for the detection of thin bone structures
  107. Research Article
  108. Towards contactless optical coherence elastography with acoustic tissue excitation
  109. Research Article
  110. Development and implementation of algorithms for automatic and robust measurement of the 2D:4D digit ratio using image data
  111. Research Article
  112. Automated high-throughput analysis of B cell spreading on immobilized antibodies with whole slide imaging
  113. Research Article
  114. Tissue segmentation from head MRI: a ground truth validation for feature-enhanced tracking
  115. Research Article
  116. Video tracking of swimming rodents on a reflective water surface
  117. Research Article
  118. MR imaging of model drug distribution in simulated vitreous
  119. Research Article
  120. Studying the extracellular contribution to the double wave vector diffusion-weighted signal
  121. Research Article
  122. Artifacts in field free line magnetic particle imaging in the presence of inhomogeneous and nonlinear magnetic fields
  123. Research Article
  124. Introducing a frequency-tunable magnetic particle spectrometer
  125. Research Article
  126. Imaging of aortic valve dynamics in 4D OCT
  127. Research Article
  128. Intravascular optical coherence tomography (OCT) as an additional tool for the assessment of stent structures
  129. Research Article
  130. Simple concept for a wide-field lensless digital holographic microscope using a laser diode
  131. Research Article
  132. Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment – a feasibility study
  133. Research Article
  134. Respiratory surface motion measurement by Microsoft Kinect
  135. Research Article
  136. Improving image quality in EIT imaging by measurement of thorax excursion
  137. Research Article
  138. A clustering based dual model framework for EIT imaging: first experimental results
  139. Research Article
  140. Three-dimensional anisotropic regularization for limited angle tomography
  141. Research Article
  142. GPU-based real-time generation of large ultrasound volumes from freehand 3D sweeps
  143. Research Article
  144. Experimental computer tomograph
  145. Research Article
  146. US-tracked steered FUS in a respiratory ex vivo ovine liver phantom
  147. Research Article
  148. Contribution of brownian rotation and particle assembly polarisation to the particle response in magnetic particle spectrometry
  149. Research Article
  150. Preliminary investigations of magnetic modulated nanoparticles for microwave breast cancer detection
  151. Research Article
  152. Construction of a device for magnetic separation of superparamagnetic iron oxide nanoparticles
  153. Research Article
  154. An IHE-conform telecooperation platform supporting the treatment of dementia patients
  155. Research Article
  156. Automated respiratory therapy system based on the ARDSNet protocol with systemic perfusion control
  157. Research Article
  158. Identification of surgical instruments using UHF-RFID technology
  159. Research Article
  160. A generic concept for the development of model-guided clinical decision support systems
  161. Research Article
  162. Evaluation of local alterations in femoral bone mineral density measured via quantitative CT
  163. Research Article
  164. Creating 3D gelatin phantoms for experimental evaluation in biomedicine
  165. Research Article
  166. Influence of short-term fixation with mixed formalin or ethanol solution on the mechanical properties of human cortical bone
  167. Research Article
  168. Analysis of the release kinetics of surface-bound proteins via laser-induced fluorescence
  169. Research Article
  170. Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine
  171. Research Article
  172. Wireless medical sensors – context, robustness and safety
  173. Research Article
  174. Sequences for real-time magnetic particle imaging
  175. Research Article
  176. Speckle-based off-axis holographic detection for non-contact photoacoustic tomography
  177. Research Article
  178. A machine learning approach for planning valve-sparing aortic root reconstruction
  179. Research Article
  180. An in-ear pulse wave velocity measurement system using heart sounds as time reference
  181. Research Article
  182. Measuring different oxygenation levels in a blood perfusion model simulating the human head using NIRS
  183. Research Article
  184. Multisegmental fusion of the lumbar spine a curse or a blessing?
  185. Research Article
  186. Numerical analysis of the biomechanical complications accompanying the total hip replacement with NANOS-Prosthetic: bone remodelling and prosthesis migration
  187. Research Article
  188. A muscle model for hybrid muscle activation
  189. Research Article
  190. Mathematical, numerical and in-vitro investigation of cooling performance of an intra-carotid catheter for selective brain hypothermia
  191. Research Article
  192. An ideally parameterized unscented Kalman filter for the inverse problem of electrocardiography
  193. Research Article
  194. Interactive visualization of cardiac anatomy and atrial excitation for medical diagnosis and research
  195. Research Article
  196. Virtualizing clinical cases of atrial flutter in a fast marching simulation including conduction velocity and ablation scars
  197. Research Article
  198. Mesh structure-independent modeling of patient-specific atrial fiber orientation
  199. Research Article
  200. Accelerating mono-domain cardiac electrophysiology simulations using OpenCL
  201. Research Article
  202. Understanding the cellular mode of action of vernakalant using a computational model: answers and new questions
  203. Research Article
  204. A java based simulator with user interface to simulate ventilated patients
  205. Research Article
  206. Evaluation of an algorithm to choose between competing models of respiratory mechanics
  207. Research Article
  208. Numerical simulation of low-pulsation gerotor pumps for use in the pharmaceutical industry and in biomedicine
  209. Research Article
  210. Numerical and experimental flow analysis in centifluidic systems for rapid allergy screening tests
  211. Research Article
  212. Biomechanical parameter determination of scaffold-free cartilage constructs (SFCCs) with the hyperelastic material models Yeoh, Ogden and Demiray
  213. Research Article
  214. FPGA controlled artificial vascular system
  215. Research Article
  216. Simulation based investigation of source-detector configurations for non-invasive fetal pulse oximetry
  217. Research Article
  218. Test setup for characterizing the efficacy of embolic protection devices
  219. Research Article
  220. Impact of electrode geometry on force generation during functional electrical stimulation
  221. Research Article
  222. 3D-based visual physical activity assessment of children
  223. Research Article
  224. Realtime assessment of foot orientation by Accelerometers and Gyroscopes
  225. Research Article
  226. Image based reconstruction for cystoscopy
  227. Research Article
  228. Image guided surgery innovation with graduate students - a new lecture format
  229. Research Article
  230. Multichannel FES parameterization for controlling foot motion in paretic gait
  231. Research Article
  232. Smartphone supported upper limb prosthesis
  233. Research Article
  234. Use of quantitative tremor evaluation to enhance target selection during deep brain stimulation surgery for essential tremor
  235. Research Article
  236. Evaluation of adhesion promoters for Parylene C on gold metallization
  237. Research Article
  238. The influence of metallic ions from CoCr28Mo6 on the osteogenic differentiation and cytokine release of human osteoblasts
  239. Research Article
  240. Increasing the visibility of thin NITINOL vascular implants
  241. Research Article
  242. Possible reasons for early artificial bone failure in biomechanical tests of ankle arthrodesis systems
  243. Research Article
  244. Development of a bending test procedure for the characterization of flexible ECoG electrode arrays
  245. Research Article
  246. Tubular manipulators: a new concept for intracochlear positioning of an auditory prosthesis
  247. Research Article
  248. Investigation of the dynamic diameter deformation of vascular stents during fatigue testing with radial loading
  249. Research Article
  250. Electrospun vascular grafts with anti-kinking properties
  251. Research Article
  252. Integration of temperature sensors in polyimide-based thin-film electrode arrays
  253. Research Article
  254. Use cases and usability challenges for head-mounted displays in healthcare
  255. Research Article
  256. Device- and service profiles for integrated or systems based on open standards
  257. Research Article
  258. Risk management for medical devices in research projects
  259. Research Article
  260. Simulation of varying femoral attachment sites of medial patellofemoral ligament using a musculoskeletal multi-body model
  261. Research Article
  262. Does enhancing consciousness for strategic planning processes support the effectiveness of problem-based learning concepts in biomedical education?
  263. Research Article
  264. SPIO processing in macrophages for MPI: The breast cancer MPI-SNLB-concept
  265. Research Article
  266. Numerical simulations of airflow in the human pharynx of OSAHS patients
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 14.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/cdbme-2015-0122/html
Scroll to top button