The impact of reverberation on speech intelligibility in cochlear implant recipients

Abstract

Listening to speech in an environment with reverberation can be challenging for both the normal and impaired auditory system. However, it has been shown for both normal- and impaired-hearing listeners that it is the late reflections that are responsible for degrading intelligibility, whereas early reflections actually aid intelligibility by increasing the effective signal-to-noise ratio. Contrastingly, studies conducted with cochlear implant (CI) recipients have suggested that CI recipients have almost no tolerance for reverberation and that they are negatively impacted by both early and late reflections. The main objective of the current study is to re-evaluate the influence of reverberation on speech intelligibility in CI recipients using more authentic virtual auditory environments. Unlike previous studies in this area, this study was conducted using a loudspeaker-based auralization system rather than non-individualized binaural room simulations. Speech intelligibility was measured in simulations of a range of actual physical rooms with plausible source-receiver distances, both with and without late reflections. The results show that the effect of reverberation is much smaller than previously suggested, especially with short source-receiver distances. Furthermore, the results suggest that, in contrast to previous literature, early reflections may not actually be detrimental to CI recipients.