Binaural intelligibility level difference with a mixed-rate strategy simulation

In noisy situations, bilateral cochlear implant (BiCI) listeners demonstrate poorer spatial release from masking compared to normal hearing (NH) listeners. One reason for this difference could be the limited access for BiCI listeners to fine structure interaural time differences (ITDs) which are crucial for binaural unmasking. Clinical processors convey speech envelopes using pulsatile high-rate (~1000 Hz) carriers, and discard the original temporal fine structure. At high rates, BiCI listeners are not sensitive to ITDs, whereas low rates (u003c 300 Hz) result in better ITD sensitivity. To preserve both ITD sensitivity and well-sampled speech envelopes, high and low rates are needed. The present study examines whether a mixed rate strategy will enable binaural unmasking in NH listeners using a 16-channel mixed-rate vocoder. Binaural intelligibility level differences were calculated from speech reception thresholds measurements in five mixed-rate configurations. Targets had a 0-μs ITD and masking speech-shaped...