scholarly journals Manufacturable 32-Channel Cochlear Electrode Array and Preliminary Assessment of Its Feasibility for Clinical Use

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 778
Author(s):  
Soowon Shin ◽  
Yoonhee Ha ◽  
Gwangjin Choi ◽  
Junewoo Hyun ◽  
Sangwoo Kim ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Signal Transmission ◽  
Round Window ◽  
Electrode Array ◽  
Lead Wire ◽  
Layer By Layer ◽  
Electrode Arrays ◽  
Insertion Force ◽  
Vertical Stiffness ◽  
Channel Electrode

(1) Background: In this study, we introduce a manufacturable 32-channel cochlear electrode array. In contrast to conventional cochlear electrode arrays manufactured by manual processes that consist of electrode-wire welding, the placement of each electrode, and silicone molding over wired structures, the proposed cochlear electrode array is manufactured by semi-automated laser micro-structuring and a mass-produced layer-by-layer silicone deposition scheme similar to the semiconductor fabrication process. (2) Methods: The proposed 32-channel electrode array has 32 electrode contacts with a length of 24 mm and 0.75 mm spacing between contacts. The width of the electrode array is 0.45 mm at its apex and 0.8 mm at its base, and it has a three-layered arrangement consisting of a 32-channel electrode layer and two 16-lead wire layers. To assess its feasibility, we conducted an electrochemical evaluation, stiffness measurements, and insertion force measurements. (3) Results: The electrochemical impedance and charge storage capacity are 3.11 ± 0.89 kOhm at 1 kHz and 5.09 mC/cm2, respectively. The V/H ratio, which indicates how large the vertical stiffness is compared to the horizontal stiffness, is 1.26. The insertion force is 17.4 mN at 8 mm from the round window, and the maximum extraction force is 61.4 mN. (4) Conclusions: The results of the preliminary feasibility assessment of the proposed 32-channel cochlear electrode array are presented. After further assessments are performed, a 32-channel cochlear implant system consisting of the proposed 32-channel electrode array, 32-channel neural stimulation and recording IC, titanium-based hermetic package, and sound processor with wireless power and signal transmission coil will be completed.

scholarly journals Radiological evaluation of a new straight electrode array compared to its precursors

2020 ◽  
Author(s):  
Manuel Christoph Ketterer ◽  
A. Aschendorff ◽  
S. Arndt ◽  
I. Speck ◽  
A. K. Rauch ◽  
...  
Keyword(s):  
Round Window ◽  
Electrode Array ◽  
Lateral Wall ◽  
Study Groups ◽  
Cone Beam ◽  
Special Focus ◽  
Electrode Arrays ◽  
Academic Center ◽  
Cochlear Morphology ◽  
Array Position

Abstract Objective The aim of this study is to examine electrode array coverage, scalar position and dislocation rate in straight electrode arrays with special focus on a new electrode array with 26 mm in lengths. Study design Retrospective study. Setting Tertiary academic center. Patients 201 ears implanted between 2013 and 2019. Main outcome measures We conducted a comparative analysis of patients implanted with lateral wall electrode arrays of different lengths (F24 = MED-EL Flex24, F26 = MED-EL Flex26, F28 = MED-EL Flex28 and F31.5 = MED-EL FlexSoft). Cone beam computed tomography was used to determine electrode array position (scala tympani (ST) versus scala vestibuli (SV), intracochlear dislocation, position of dislocation and insertion angle). Results Study groups show no significant differences regarding cochlear size which excludes influences by cochlear morphology. As expected, the F24 showed significant shorter insertion angles compared to the longer electrode arrays. The F26 electrode array showed no signs of dislocation or SV insertion. The electrode array with the highest rate of ST dislocations was the F31.5 (26.3%). The electrode array with the highest rates of SV insertions was the F28 (5.75%). Most of the included electrode arrays dislocate between 320° and 360° (mean: 346.4°; range from 166° to 502°). Conclusion The shorter F24 and the new straight electrode array F26 show less or no signs of scalar dislocation, neither for round window nor for cochleostomy insertion than the longer F28 and the F31.5 array. As expected, the cochlear coverage is increasing with length of the electrode array itself but with growing risk for scalar dislocation and with the highest rates of dislocation for the longest electrode array F31.5. Position of intracochlear dislocation is in the apical cochlear part in the included lateral wall electrode arrays.

scholarly journals Frictional Behavior of Cochlear Electrode Array Is Dictated by Insertion Speed and Impacts Insertion Force

2021 ◽  
Vol 11 (11) ◽  
pp. 5162
Author(s):  
Dana Dohr ◽  
Nicklas Fiedler ◽  
Wolfram Schmidt ◽  
Niels Grabow ◽  
Robert Mlynski ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Cochlear Implant ◽  
Electrode Array ◽  
Mechanical Trauma ◽  
Electrode Arrays ◽  
Friction Behavior ◽  
Insertion Force ◽  
Friction Coefficients ◽  
Electrode Insertion ◽  
The Impact

Background: During cochlear implantation, the electrode array has significant friction with the sensitive endocochlear lining and causes mutual mechanical trauma while the array is being inserted. Both, the impact of insertion speed on electrode friction and the relationship of electrode insertion force and friction have not been adequately investigated to date. Methods: In this study, friction coefficients between a CI electrode array (31.5 mm) and a tissue simulating the endocochlear lining have been acquired, depending on different insertion speeds (0.1, 0.5, 1.0, 1.5, and 2.0 mm/s). Additionally, the electrode insertion forces during the placing into a scala tympani model were recorded and correlated with the friction coefficient. Results: It was shown that the friction coefficient reached the lowest value at an insertion speed of 0.1 mm/s (0.24 ± 0.13), a maximum occurred at 1.5 mm/s (0.59 ± 0.12), and dropped again at 2 mm/s (0.45 ± 0.11). Similar patterns were observed for the insertion forces. Consequently, a high correlation coefficient (0.9) was obtained between the insertion forces and friction coefficients. Conclusion: The present study reveals a non-linear increase in electrode array friction, when insertion speed raises and reports a high correlation between friction coefficient and electrode insertion force. This dependence is a relevant future parameter to evaluate and reduce cochlear implant insertion trauma. Significance statement: Here, we demonstrated a dependence between cochlear electrode insertion speed and its friction behavior and a high correlation to insertion force. Our study provides valuable information for the evaluation and prevention of cochlear implant insertion trauma and supports the optimization of cochlear electrode arrays regarding friction characteristics.

Anatomy of the round Window with Respect to Cochlear Implant Surgery

1987 ◽  
Vol 96 (1_suppl) ◽  
pp. 17-19 ◽  
Author(s):  
A. R. Clifford ◽  
W. P. R. Gibson
Keyword(s):  
Round Window ◽  
Electrode Array ◽  
Careful Analysis ◽  
Cochlear Duct ◽  
Video Recordings ◽  
Cochlear Implant Surgery ◽  
Electrode Insertion ◽  
Channel Electrode ◽  
Temporal Bones ◽  
Insertion Length

Twenty-three human temporal bones were dissected to study the anatomy of the round window with respect to cochlear implantation. Information was also gathered concerning the passage of a 22-channel electrode array along the cochlear duct by using cochlear surface dissection preparations. The insertion length and any insertion trauma were noted both by observation at the time of insertion and by careful analysis of video recordings. The crista semilunaris did not interfere with smooth electrode insertion. The recommendation is made that enlarging the round window anteroinferiorly is unnecessary and potentially hazardous in most cases.

scholarly journals Cochlearis implantátumok különböző, előre görbített elektródasorainak elhelyezkedése a cochlea tengelyéhez viszonyítva. Radiológiai vizsgálat a perimodiolaritás mértékének megállapítására

2019 ◽  
Vol 160 (31) ◽  
pp. 1216-1222
Author(s):  
Ádám Perényi ◽  
Roland Nagy ◽  
Balázs Dimák ◽  
Miklós Csanády ◽  
József Jóri ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Ganglion Cells ◽  
Round Window ◽  
Electrode Array ◽  
Neural Responses ◽  
Electrode Arrays ◽  
Performance Abilities ◽  
Length Width ◽  
Electrophysiological Result ◽  
The Mean

Abstract: Introduction: The cochlear implants vary in electrodes in terms of length, width and proximity to the modiolus. The precurved electrode arrays could be placed closer to the modiolus and the ganglion cells compared to straight electrodes. The two types of electrode arrays provide different electrophysiological characteristics; however, proximity to the modiolus may lead to better hearing performance. Aim: To investigate our preliminary electrophysiological results that suggest that the Slim Modiolar (SM) electrode array has the potential to elicit similar neural responses as the thicker perimodiolar (Contour Advance, CA) electrode from the same generation of implants. Method: Subjects that were implanted either with CA or SM electrodes were enrolled, 54 consecutive subjects in each group. All electrodes were introduced into the cochlea via the round window. The diameter of the largest turn of the electrode arrays within the cochlea was measured through postoperative radiography. The energy consumption parameters were estimated 2 months after implantation. Results: The mean of the largest turns of the arrays within the cochlea was 4.2 ± 0.5 mm in the SM group and 4.9 ± 1.1 mm in the CA group. ‘Auto power’ was 44.81 ± 5.05% and 50.85 ± 8.35% with SM and CA, respectively. Estimated energy consumption was lower with SM. The differences were statistically significant. Conclusion: Our measurements for a large cohort in each group suggest that the SM electrode array takes a significantly closer position to the modiolus than the CA. This finding supports our earlier electrophysiological result and indicates better performance abilities. Orv Hetil. 2019; 160(31): 1216–1222.

scholarly journals Fabrication of Convex PDMS–Parylene Microstructures for Conformal Contact of Planar Micro-Electrode Array

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1436
Author(s):  
Woo Ram Lee ◽  
Changkyun Im ◽  
Hae-Yong Park ◽  
Jong-Mo Seo ◽  
Jun-Min Kim
Keyword(s):  
Electrochemical Impedance ◽  
Brain Connectivity ◽  
Electrode Array ◽  
Theoretical Background ◽  
Electrode Site ◽  
Pattern Generation ◽  
Electrode Arrays ◽  
Silicon Mold ◽  
Micro Pattern ◽  
Pdms Replica

Polymer-based micro-electrode arrays (MEAs) are gaining attention as an essential technology to understand brain connectivity and function in the field of neuroscience. However, polymer based MEAs may have several challenges such as difficulty in performing the etching process, difficulty of micro-pattern generation through the photolithography process, weak metal adhesion due to low surface energy, and air pocket entrapment over the electrode site. In order to compensate for the challenges, this paper proposes a novel MEA fabrication process that is performed sequentially with (1) silicon mold preparation; (2) PDMS replica molding, and (3) metal patterning and parylene insulation. The MEA fabricated through this process possesses four arms with electrode sites on the convex microstructures protruding about 20 μm from the outermost layer surface. The validity of the convex microstructure implementation is demonstrated through theoretical background. The electrochemical impedance magnitude is 204.4 ± 68.1 kΩ at 1 kHz. The feasibility of the MEA with convex microstructures was confirmed by identifying the oscillation in the beta frequency band (13–30 Hz) in the electrocorticography signal of a rat olfactory bulb during respiration. These results suggest that the MEA with convex microstructures is promising for applying to various neural recording and stimulation studies.

scholarly journals Current Stimulation of the Midbrain Nucleus in Pigeons for Avian Flight Control

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 788
Author(s):  
Jung-Woo Jang ◽  
Changhoon Baek ◽  
Sunhyo Kim ◽  
Tae-Kyeong Lee ◽  
Gwang-Jin Choi ◽  
...  
Keyword(s):  
Flight Control ◽  
Motion Tracking ◽  
Electrode Array ◽  
Movement Control ◽  
Basic Research ◽  
Flight Behavior ◽  
Electrode Arrays ◽  
Channel Electrode ◽  
The Brain ◽  
Stimulation Of

A number of research attempts to understand and modulate sensory and motor skills that are beyond the capability of humans have been underway. They have mainly been expounded in rodent models, where numerous reports of controlling movement to reach target locations by brain stimulation have been achieved. However, in the case of birds, although basic research on movement control has been conducted, the brain nuclei that are triggering these movements have yet to be established. In order to fully control flight navigation in birds, the basic central nervous system involved in flight behavior should be understood comprehensively, and functional maps of the birds’ brains to study the possibility of flight control need to be clarified. Here, we established a stable stereotactic surgery to implant multi-wire electrode arrays and electrically stimulated several nuclei of the pigeon’s brain. A multi-channel electrode array and a wireless stimulation system were implanted in thirteen pigeons. The pigeons' flight trajectories on electrical stimulation of the cerebral nuclei were monitored and analyzed by a 3D motion tracking program to evaluate the behavioral change, and the exact stimulation site in the brain was confirmed by the postmortem histological examination. Among them, five pigeons were able to induce right and left body turns by stimulating the nuclei of the tractus occipito-mesencephalicus (OM), nucleus taeniae (TN), or nucleus rotundus (RT); the nuclei of tractus septo-mesencephalicus (TSM) or archistriatum ventrale (AV) were stimulated to induce flight aviation for flapping and take-off with five pigeons.

scholarly journals Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Graziela de Souza Queiroz Martins ◽  
Rubens Vuono Brito Neto ◽  
Robinson Koji Tsuji ◽  
Eloisa Maria Mello Santiago Gebrim ◽  
Ricardo Ferreira Bento
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Electrode Array ◽  
Hearing Preservation ◽  
Round Window Membrane ◽  
Residual Hearing ◽  
Electrode Arrays ◽  
Minimal Trauma ◽  
Electrode Insertion ◽  
Temporal Bones

Hypothesis. This study aimed to evaluate whether there is a difference in the degree of intracochlear trauma when the cochlear implant electrode arrays is inserted through different quadrants of the round window membrane.Background. The benefits of residual hearing preservation in cochlear implant recipients have promoted the development of atraumatic surgeries. Minimal trauma during electrode insertion is crucial for residual hearing preservation.Methods. In total, 25 fresh human temporal bones were subjected to mastoidectomy and posterior tympanotomy. The cochlear implant electrode array was inserted through the anterosuperior quadrant of the round window membrane in 50% of the bones and through the anteroinferior quadrant in the remaining 50%. The temporal bones were dehydrated, embedded in epoxy, serially polished, stained, viewed through a stereomicroscope, and photographed with the electrode arraysin situ. The resulting images were analyzed for signs of intracochlear trauma.Results. Histological examinations revealed varying degrees of damage to the intracochlear structures, although the incidence and severity of intracochlear trauma were not influenced by the quadrant of insertion.Conclusions. The incidence and severity of intracochlear trauma were similar in all samples, irrespective of electrode array insertion through the anterosuperior or anteroinferior quadrant of the round window membrane.

scholarly journals Histological evaluation of a cochlear implant electrode array with electrically activated shape change for perimodiolar positioning

2018 ◽  
Vol 4 (1) ◽  
pp. 145-148
Author(s):  
Thomas S. Rau ◽  
N.úha Suzaly ◽  
Nick Pawsey ◽  
Silke Hügl ◽  
Lenarz Majdani ◽  
...  
Keyword(s):  
Shape Memory ◽  
Inner Ear ◽  
Shape Change ◽  
Round Window ◽  
Small Diameter ◽  
Electrode Array ◽  
Electrical Heating ◽  
Histological Evaluation ◽  
Electrode Arrays ◽  
Nitinol Wire

AbstractFor the treatment of deafness or severe hearing loss cochlear implants (CI) are used to stimulate the auditory nerve of the inner ear. In order to produce an electrode array which is both atraumatic and reaches a perimodiolar final position a design featuring shape memory effect was proposed. A Nitinol wire with a diameter of 100 μm was integrated in a state of the art lateral wall electrode array. The wire serves as an actuator after it has been ‘trained’ to adopt the spiral shape of an average human cochlea. Three small diameter platinum-iridium wires (each 20 μm) were crimped to the Nitinol wire in order to produce thermal energy. An insertion test was pursued using a human temporal bone specimen. The prototype electrode array was cooled down by means of immersion in ice water and freeze spray to enable sufficient straightening. Thereafter, insertion into the cochlea through the round window as performed. Insertion was feasible but difficult as premature curling of the electrode occurred during the movement towards the inner ear while passing the middle ear cavity. Therefore, the insertion had to be performed faster than usual. The shape memory actuator was subsequently activated with 450mA current at 5V for 3 seconds. After insertion the specimen was embedded in epoxy resin, microgrinded and all histological slices were assessed for trauma. Perimodiolar position was achieved. No insertion trauma was observed and there were no indications of thermal damage caused by the electrical heating. To the best of our knowledge, this is the first histological evaluation of the insertion trauma caused by an electrically activated shape memory electrode array. These promising results support further research on shape memory CI electrode arrays.

Optimal Path Planning for Robotic Insertion of Steerable Electrode Arrays in Cochlear Implant Surgery

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Jian Zhang ◽  
J. Thomas Roland ◽  
Spiros Manolidis ◽  
Nabil Simaan
Keyword(s):  
Path Planning ◽  
Cochlear Implant ◽  
Optimal Path ◽  
Electrode Array ◽  
Scala Tympani ◽  
Electrode Arrays ◽  
Insertion Force ◽  
Optimal Path Planning ◽  
Cochlear Implant Surgery ◽  
Electrode Insertion

This paper presents an optimal path planning method of steerable electrode arrays for robot-assisted cochlear implant surgery. In this paper, the authors present a novel design of steerable electrode arrays that can actively bend at the tip. An embedded strand in the electrode array provides an active steering degrees-of-freedom (DoF). This paper addresses the calibration of the steerable electrode array and the optimal path planning for inserting it into planar and three-dimensional scala tympani models. The goal of the path planning is to minimize the intracochlear forces that the electrode array applies on the walls of the scala tympani during insertion. This problem is solved by designing insertion path planning algorithms that provide best fit between the shape of the electrode array and the curved scala tympani during insertion. Optimality measures that account for shape discrepancies between the steerable electrode array and the scala tympani are used to solve for the optimal path planning of the robot. Different arrangements of DoF and insertion speed force feedback (ISFF) are simulated and experimentally validated in this paper. A quality of insertion metric describing the gap between the steerable electrode array and the scala tympani model is presented and its correspondence to the insertion force is shown. The results of using 1DoF, 2DoF, and 4DoF electrode array insertion setups are compared. The 1DoF insertion setup uses nonsteerable electrode arrays. The 2DoF insertion setup uses single axis insertion with steerable electrode arrays. The 4DoF insertion setup allows full control of the insertion depth and the approach angle of the electrode with respect to the cochlea while using steerable electrode arrays. It is shown that using steerable electrode arrays significantly reduces the maximal insertion force (59.6% or more) and effectively prevents buckling of the electrode array. The 4DoF insertion setup further reduces the maximal electrode insertion forces. The results of using ISFF for steerable electrodes show a slight decrease in the insertion forces in contrast to a slight increase for nonsteerable electrodes. These results show that further research is required in order to determine the optimal ISFF control law and its effectiveness in reducing electrode insertion forces.

scholarly journals The Pull-Back Technique for the 532 Slim Modiolar Electrode

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
C. Riemann ◽  
H. Sudhoff ◽  
I. Todt
Keyword(s):  
Temporal Bone ◽  
Round Window ◽  
Spiral Ganglion ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Current Spread ◽  
Temporal Bones ◽  
Hearing Outcomes ◽  
White Marker

Introduction. The distance between the modiolus and the electrode array is one factor that has become the focus of many discussions and studies. Positioning the electrode array closer to the spiral ganglion with the goal of reducing the current spread has been shown to improve hearing outcomes. The perimodiolar electrode arrays can be complemented with a surgical manoeuvre called the pull-back technique. This study focuses its attention on the recently developed 532 slim modiolar electrode. Objective. To investigate the intracochlear movements and pull-back technique for the 532 slim modiolar electrode. Material and Methods. A decapping procedure of the cochlea was performed on 5 temporal bones. The electrode array was inserted, and the intracochlear movements were microscopically examined and digitally captured. Three situations were analysed: the initial insertion, the overinsertion, and the pull-back position. The position of the three white markers of the electrode array in relation to the round window (RW) was evaluated while performing these three actions. Results. The initial insertion achieved an acceptable perimodiolar position of the electrode array, but a gap was still observed between the mid-portion of the array and the modiolus (the first white marker was seen in the RW). When we inserted the electrode more deeply, the mid-portion of the array was pushed away from the modiolus (the second and third white markers were seen in the RW). After applying the pull-back technique, the gap observed during the initial insertion disappeared, resulting in an optimal perimodiolar position (the first white marker was once again visible in the RW). Conclusion. This temporal bone study demonstrated that when applying the pull-back technique for the 532 slim modiolar electrode, a closer proximity to the modiolus was achieved when the first white marker of the electrode array was visible in the round window.

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