gms | German Medical Science

Objectives: The aim of this prospective study is to evaluate the subject’s long-term benefits of chronic electrical stimulation of low frequency regions in the cochlea. Additionally, the study aimed to evaluate different channels arrangements in the cochlea on speech perception abilities.

Materials and Methods: Newly implanted subjects with a MED-EL cochlear implant and a fully inserted standard electrode participate in the study. To evaluate the effect of apical stimulation on speech perception, 3 different electrode configurations have been defined for the 12 electrode array: A) 8 most apical electrodes only (condition: apical), B) 8 most basal electrodes only (condition basal), C) 8 electrodes spread across the whole array (condition spread). The study follows an ABCABC crossover design with one month familiarization for each condition except for the first one, which is being administered for three months. Starting conditions are being randomized across the patients and every condition is being repeated during the trial in order to compensate for learning effects.

Tests include various pre-recorded materials: Freiburger monosyllables, vowels and consonants as well as HSM sentences in quiet and noise.

Results: Preliminary results indicate that a limitation of the stimulated region within the cochlea has a detrimental effect on subject performance. This detrimental effect is significantly more pronounced when using the eight apical-most channels compared to using the eight basal-most channels. Best performance among the tested eight-channel conditions is achieved by spreading these channels from base to apex, thus maximizing the stimulated cochlear region, although so far no significant difference in performance has been found between the basal and the spread condition.

Conclusions: Preliminary data of this chronic study suggest that cochlear implant recipients may benefit from apical stimulation of the cochlea as achieved by deep electrode insertion.