The effects of background noise and reverberation on speech perception in cochlear implant users

Abstract

Indoor noise and reverberation interfere with speech understanding for listeners. Degradation in cochlear implant (CI) processing presents additional challenges for CI users to understand noisy and reverberant speech. Inthis study, we investigated the effect of adverse acoustics on speech perception on three tasks that changed in difficulty and increasing need for top-down processing: (1) word recall, (2) sentence recognition, and (3) conversation comprehension. Each task was tested in five conditions that varied in combinations of adverse acoustics from reverberation (i.e., anechoic, 0.4s RT, vs 1.2s RT) and noise (i.e., quiet versus Speech-shaped-noise at −3dB). We compared performances from normal-hearing (NH) listeners and bilateral CI users between 15 and 25 years old. Preliminary results show that while NH listeners may have some tolerance for speech perception under adverse acoustics, CI users experienced more graded performance deterioration with increasing reverberation and noise. Moreover, we observed task-dependent performance change across adverse acoustic conditions in both NH and CI listeners: While some context (i.e., sentences) may help speech perception, comprehension based on pragmatic language processing (i.e., conversations) is vulnerable under difficult listening situations. These results provide insights on how NH and CI listeners differ in their access to top-down processing in real-world speech perception.