Possible implications of interaural mismatch in the place-of-stimulation on spatial release from masking in cochlear implant listeners

Abstract

Recent research suggests that bilateral cochlear implant (CI) users have improved speech intelligibility in noisy environments compared to unilateral CI users. This may not be surprising given that in normal hearing (NH) listeners, binaural hearing allows them to localize sounds and this ability allows them to benefit from a spatial release from masking (SRM). However, SRM benefits are much less in CI users and vary amongst users. This may be due to the interaural mismatch in the place-of-stimulation across the ears in CI users and occurs due to differences in neural survival and electrode implantation depth across the ears, leading to different parts of the cochlea being excited by electrodes of the same number. Data will be presented that shows that with increasing interaural mismatch, CI users typically heard lateralized or multiple sounds. In some CI users, interaural mismatches greater than 3 mm leads to an inability to use binaural cues. These effects may impact a CI user's ability to obtain SRM. Pr...