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.
