Influence of electrode position on the speech intelligibility and electrophysiology in cochlear implants

Introduction Positioning the CI electrode into the scala tympani may increase the intracochlear trauma due to a scalar translocation of the electrode into the scala vestibuli. The aim of this study was to investigate whether scalar translocations influence the postoperative electrophysiological and speech audiometric outcome within a large group of patients.

Methods The investigations are performed retrospectively on 255 adult patients with a Nucleus^® Slim Modiolar or a Contour Advance electrode (Cochlear^® Ltd.). The electrode position was assessed by postoperative CT or DVT imaging. Intraoperative and one year after first fitting measured ECAP thresholds were examined as well as the postoperative speech intelligibility in quiet using the Freiburg monosyllable (words) test at 65 dB.

Results The incidence of a translocations was significantly lower with the Slim Modiolar than with the Contour Advance electrode (5.1 %  versus 32.3 % ). No significant differences in speech recognition were found between translocations and scala tympani insertions with both electrodes. Compared to scala tympani insertions, electrode translocations yielded higher ECAP thresholds at apical and medial electrode contacts (p < 0.05).

Discussion In this study it could be shown that patients with a scalar translocation have higher apical ECAP threshold compared to patients with a full scala tympani insertion. However, a translocation does not seem to lead to a poorer speech intelligibility in quiet one year after the first fitting.

Poster-PDF A-1228.pdf

Publication History

Article published online:
13 May 2021