Sequential stream segregation using temporal periodicity cues in cochlear implant recipients

Abstract

Sequential stream segregation involves the ability of a listener to perceptually segregate two rapidly alternating sounds into different perceptual streams. By studying auditory streaming in cochlear implants (CIs), one can obtain a better understanding of the cues that CI recipients can use to segregate different sound sources, which may have relevance to such everyday activities as the understanding of speech in background noise. This study focuses on the ability of CI users to use temporal periodicity cues to perform auditory stream segregation. A rhythmic discrimination task involving sequences of alternating amplitude-modulated (AM) noises is used. The results suggest that most CI users can stream AM noise bursts at relatively low modulation frequencies (near 80 Hz AM), but that this ability diminishes at higher modulation frequencies. Additionally, the ability of CI users to perform streaming using temporal periodicity cues appears to be comparable to that of normal-hearing listeners. These results imply that CI subjects may in certain contexts (i.e., when the talker has a low fundamental frequency voice) be able to use temporal periodicity cues to segregate and thus understand the voices of competing talkers.