Examining the effects of reverberant environments and interaural level differences for bilateral cochlear implant users

Reverberant environments and background noise each pose significant challenges for cochlear implant listeners, and their combined effects can be even more detrimental. The effect of reverberation may be magnified for bilateral cochlear implant users since reverberant environments can result in a decrease in the interaural coherence of signals to the two ears, which can degrade binaural abilities. Previous research from our laboratory has shown that adding an interaural level difference can help foster binaural fusion in the presence of decreased interaural coherence. This study examined if adding an interaural level difference can also improve speech perception in reverberant environments for bilateral cochlear implant users. Participants were tested using AzBio sentences with a multi-talker babble background, either with or without a simulated reverberant environment and with or without the addition of a large interaural level difference. Preliminary data indicates that performance markedly decreased with the simulated reverberant environment. However, adding a large interaural level difference improved speech recognition in a reverberant environment, but not for all participants.