scholarly journals The relation between polarity sensitivity and neural degeneration in a computational model of cochlear implant stimulation

2021 ◽  
pp. 108413
Author(s):  
Randy K. Kalkman ◽  
Jeroen J. Briaire ◽  
David M.T. Dekker ◽  
Johan H.M. Frijns
Keyword(s):  
Cochlear Implant ◽  
Computational Model ◽  
Neural Degeneration ◽  
Polarity Sensitivity

scholarly journals Polarity Sensitivity as a Potential Correlate of Neural Degeneration in Cochlear Implant Users

2020 ◽  
Vol 21 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Quentin Mesnildrey ◽  
Frédéric Venail ◽  
Robert P. Carlyon ◽  
Olivier Macherey
Keyword(s):  
Cochlear Implant ◽  
Neural Degeneration ◽  
Polarity Sensitivity

scholarly journals Neural Tissue Degeneration in Rosenthal’s Canal and Its Impact on Electrical Stimulation of the Auditory Nerve by Cochlear Implants: An Image-Based Modeling Study

2020 ◽  
Vol 21 (22) ◽  
pp. 8511
Author(s):  
Kiran Kumar Sriperumbudur ◽  
Revathi Appali ◽  
Anthony W. Gummer ◽  
Ursula van Rienen
Keyword(s):  
Cochlear Implant ◽  
Cochlear Implants ◽  
Auditory Nerve ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Sensorineural Deafness ◽  
Neural Tissue ◽  
Neural Degeneration ◽  
Tissue Degeneration ◽  
Ganglion Neurons

Sensorineural deafness is caused by the loss of peripheral neural input to the auditory nerve, which may result from peripheral neural degeneration and/or a loss of inner hair cells. Provided spiral ganglion cells and their central processes are patent, cochlear implants can be used to electrically stimulate the auditory nerve to facilitate hearing in the deaf or severely hard-of-hearing. Neural degeneration is a crucial impediment to the functional success of a cochlear implant. The present, first-of-its-kind two-dimensional finite-element model investigates how the depletion of neural tissues might alter the electrically induced transmembrane potential of spiral ganglion neurons. The study suggests that even as little as 10% of neural tissue degeneration could lead to a disproportionate change in the stimulation profile of the auditory nerve. This result implies that apart from encapsulation layer formation around the cochlear implant electrode, tissue degeneration could also be an essential reason for the apparent inconsistencies in the functionality of cochlear implants.

Prediction of vowel identification for cochlear implant using a computational model

2016 ◽  
Vol 85 ◽  
pp. 19-28 ◽  
Author(s):  
Hyejin Yang ◽  
Jong Ho Won ◽  
Soojin Kang ◽  
Il Joon Moon ◽  
Sung Hwa Hong ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Computational Model ◽  
Vowel Identification

scholarly journals Polarity Sensitivity in Pediatric and Adult Cochlear Implant Listeners

2019 ◽  
Vol 23 ◽  
pp. 233121651986298 ◽  
Author(s):  
Kelly N. Jahn ◽  
Julie G. Arenberg
Keyword(s):  
Cochlear Implant ◽  
Dynamic Range ◽  
Single Channel ◽  
Spiral Ganglion ◽  
High Amplitude ◽  
Electrical Stimulus ◽  
Polarity Sensitivity ◽  
The Difference ◽  
Phoneme Perception ◽  
Ganglion Neurons

Modeling data suggest that sensitivity to the polarity of an electrical stimulus may reflect the integrity of the peripheral processes of the spiral ganglion neurons. Specifically, better sensitivity to anodic (positive) current than to cathodic (negative) current could indicate peripheral process degeneration or demyelination. The goal of this study was to characterize polarity sensitivity in pediatric and adult cochlear implant listeners (41 ears). Relationships between polarity sensitivity at threshold and (a) polarity sensitivity at suprathreshold levels, (b) age-group, (c) preimplantation duration of deafness, and (d) phoneme perception were determined. Polarity sensitivity at threshold was defined as the difference in single-channel behavioral thresholds measured in response to each of two triphasic pulses, where the central high-amplitude phase was either cathodic or anodic. Lower thresholds in response to anodic than to cathodic pulses may suggest peripheral process degeneration. On the majority of electrodes tested, threshold and suprathreshold sensitivity was lower for anodic than for cathodic stimulation; however, dynamic range was often larger for cathodic than for anodic stimulation. Polarity sensitivity did not differ between child- and adult-implanted listeners. Adults with long preimplantation durations of deafness tended to have better sensitivity to anodic pulses on channels that were estimated to interface poorly with the auditory nerve; this was not observed in the child-implanted group. Across subjects, duration of deafness predicted phoneme perception performance. The results of this study suggest that subject- and electrode-dependent differences in polarity sensitivity may assist in developing customized cochlear implant programming interventions for child- and adult-implanted listeners.

scholarly journals Polarity Sensitivity of Human Auditory Nerve Fibers Based on Pulse Shape, Cochlear Implant Stimulation Strategy and Array

2021 ◽  
Vol 15 ◽  
Author(s):  
Amirreza Heshmat ◽  
Sogand Sajedi ◽  
Anneliese Schrott-Fischer ◽  
Frank Rattay
Keyword(s):  
Cochlear Implant ◽  
Auditory Nerve ◽  
Computational Study ◽  
Three Dimensional ◽  
Element Model ◽  
Nerve Fibers ◽  
Polarity Sensitivity ◽  
Auditory Nerve Fibers ◽  
Asymmetric Pulse ◽  
Peripheral Site

Neural health is of great interest to determine individual degeneration patterns for improving speech perception in cochlear implant (CI) users. Therefore, in recent years, several studies tried to identify and quantify neural survival in CI users. Among all proposed techniques, polarity sensitivity is a promising way to evaluate the neural status of auditory nerve fibers (ANFs) in CI users. Nevertheless, investigating neural health based on polarity sensitivity is a challenging and complicated task that involves various parameters, and the outcomes of many studies show contradictory results of polarity sensitivity behavior. Our computational study benefits from an accurate three-dimensional finite element model of a human cochlea with realistic human ANFs and determined ANF degeneration pattern of peripheral part with a diminishing of axon diameter and myelination thickness based on degeneration levels. In order to see how different parameters may impact the polarity sensitivity behavior of ANFs, we investigated polarity behavior under the application of symmetric and asymmetric pulse shapes, monopolar and multipolar CI stimulation strategies, and a perimodiolar and lateral CI array system. Our main findings are as follows: (1) action potential (AP) initiation sites occurred mainly in the peripheral site in the lateral system regardless of stimulation strategies, pulse polarities, pulse shapes, cochlear turns, and ANF degeneration levels. However, in the perimodiolar system, AP initiation sites varied between peripheral and central processes, depending on stimulation strategies, pulse shapes, and pulse polarities. (2) In perimodiolar array, clusters formed in threshold values based on cochlear turns and degeneration levels for multipolar strategies only when asymmetric pulses were applied. (3) In the perimodiolar array, a declining trend in polarity (anodic threshold/cathodic threshold) with multipolar strategies was observed between intact or slight degenerated cases and more severe degenerated cases, whereas in the lateral array, cathodic sensitivity was noticed for intact and less degenerated cases and anodic sensitivity for cases with high degrees of degeneration. Our results suggest that a combination of asymmetric pulse shapes, focusing more on multipolar stimulation strategies, as well as considering the distances to the modiolus wall, allows us to distinguish the degeneration patterns of ANFs across the cochlea.

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