Impact of Reverberation on Speech Perception and Sound Localization Accuracy in Cochlear Implant Users With Single-Sided Deafness.

Abstract

The aim of this study was to compare the impact of reverberation on sound localization accuracy and speech perception in noise between subjects with single-sided deafness using a cochlear implant (SSD-CI) and a normal-hearing control group. Nine SSD-CI subjects and 21 normal-hearing subjects participated in the study. In Experiment 1, the sound localization accuracy was measured with and without reverberation. In Experiment 2, speech reception thresholds were determined with four asymmetrically arranged noise sources in free-field and in reverberation. For the realization of reverberation, a room simulation system comprising of 128 loudspeakers was used. No significant impact of reverberation was found on the sound localization accuracy of the SSD-CI subjects (free-field: 12.6°, reverberation: 11.9°), whereas the normal-hearing subjects performed significantly worse in reverberation (free-field: 1.8°, reverberation: 3.3°).Both subject groups experienced significantly deteriorated speech reception thresholds due to reverberation (pSSD-CI = 0.008, pNH < 0.001). Mean speech reception thresholds in the SSD-CI subjects were -9.7 dB SNR (free-field) and -4.2 dB SNR (reverberation) and a median individual decrease of 5.7 dB SNR in reverberation. Mean speech reception thresholds in the normal-hearing group were -14.0 dB SNR (free-field) and -10.3 dB SNR (reverberation). A strong deterioration of sound localization accuracy due to reverberation did not occur. However, although partial restoration of binaural hearing is assumed in SSD-CI users, the impact of reverberation on speech perception in noise is much stronger compared to normal-hearing.