In Brief:
Bilateral cochlear implant (BCI) users have shown reduced binaural abilities as compared to listeners with normal hearing. Although BCI users have been shown to be sensitive to interaural differences of levels, their sensitivity to interaural time differences is poorer, and this is likely the reason that as a group they have shown limited benefit to speech intelligibility from spatial cues, as listeners with normal hearing do. A method for enhancing the binaural cues available to BCI users is investigated, which involved computing instantaneous interaural time differences in the low-frequency region (which are present naturally in a BCI configuration, although not typically available to BCI users due to the signal processing of the devices), and converting them to low-frequency interaural differences of levels (which are not present naturally, but are useable by normal-hearing listeners). The efficacy of such manipulation on the speech intelligibility of a target talker presented to one side of the head, in the presence of a masker talker on the other is evaluated. BCI patients showed greater speech intelligibility with enhanced than with naturally occurring binaural cues. Thus, improved speech intelligibility under some listening configurations is possible using the binaural cues available to BCI users.
