Intraoperative ECAP amplitudes compared to postoperative speech understanding in adult CI users.

Introduction

An important preoperative question of cochlear implant (CI) candidates is the likelihood of success of CI implantation regarding speech understanding(SV). Single preoperative influencing factors allow a rough estimation, but a precise assessment of postoperative SV is not possible due to missing predictors. The aim of this study is to investigate the potential correlation of intra- and postoperative Electrically evoked compound action potentials (ECAPs) with speech understanding.

Material and Methods

A retrospective analysis (2016-17) identified 162 CI patients in whom ECAP thresholds were routinely recorded intraoperatively at all 22 electrodes. We analyzed the correlation of ECAP thresholds with postoperative speech understanding one year after CI surgery and over a mean period of 2.1 years. In addition, ECAPs from two perimodiolar electrodes were compared.

Results

There was no correlation of ECAP thresholds with postoperative speech understanding. Consequently, the ECAP thresholds cannot give any information about the potential SV with CI. In the follow-up, a decrease of ECAP thresholds by CI stimulation was noticeable. The perimodiolar electrodes showed significant differences in ECAP thresholds in the basal and apical regions of the cochlea.

Summary

Intraoperative ECAP measurement is not a predictor of postoperative SV. The ECAP thresholds decrease by stimulation with the CI, accordingly, it can be assumed that stimulation with the CI has a positive effect on spiral ganglion cell activity. The difference of the ECAP thresholds of the perimodiolar electrodes can give information about the distance of the electrode to the modiolus.

Publication History

Article published online:
24 May 2022