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Journal of the Association for Research in Otolaryngology

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Open Access 26-01-2024 | Cochlear Implant | Original Article: General Research

Insights Into Electrophysiological Metrics of Cochlear Health in Cochlear Implant Users Using a Computational Model

Authors: Marko Takanen, Stefan Strahl, Konrad Schwarz

Published in: Journal of the Association for Research in Otolaryngology | Issue 1/2024

Abstract

Purpose

The hearing outcomes of cochlear implant users depend on the functional status of the electrode-neuron interface inside the cochlea. This can be assessed by measuring electrically evoked compound action potentials (eCAPs). Variations in cochlear neural health and survival are reflected in eCAP-based metrics. The difficulty in translating promising results from animal studies into clinical use has raised questions about to what degree eCAP-based metrics are influenced by non-neural factors. Here, we addressed these questions using a computational model.

Methods

A 2-D computational model was designed to simulate how electrical signals from the stimulating electrode reach the auditory nerve fibers distributed along the cochlea, evoking action potentials that can be recorded as compound responses at the recording electrodes. Effects of physiologically relevant variations in neural survival and in electrode-neuron and stimulating-recording electrode distances on eCAP amplitude growth functions (AGFs) were investigated.

Results

In line with existing literature, the predicted eCAP AGF slopes and the inter-phase gap (IPG) effects depended on the neural survival, but only when the IPG effect was calculated as the difference between the slopes of the two AGFs expressed in linear input–output scale. As expected, shallower eCAP AGF slopes were obtained for increased stimulating-recording electrode distance and larger eCAP thresholds for greater electrode-neuron distance. These non-neural factors had also minor interference on the predicted IPG effect.

Conclusions

The model predictions demonstrate previously found dependencies of eCAP metrics on neural survival and non-neural aspects. The present findings confirm data from animal studies and provide insights into applying described metrics in clinical practice.

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Title: Insights Into Electrophysiological Metrics of Cochlear Health in Cochlear Implant Users Using a Computational Model
Authors: Marko Takanen
Stefan Strahl
Konrad Schwarz
Publication date: 26-01-2024
Publisher: Springer US
Keyword: Cochlear Implant
Published in: Journal of the Association for Research in Otolaryngology / Issue 1/2024
Print ISSN: 1525-3961
Electronic ISSN: 1438-7573
DOI: https://doi.org/10.1007/s10162-023-00924-z

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Insights Into Electrophysiological Metrics of Cochlear Health in Cochlear Implant Users Using a Computational Model

Abstract

Purpose

Methods

Results

Conclusions

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Abstract

Purpose

Methods

Results

Conclusions

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