Does random temporal jitter reduce onset dominance in temporal weighting functions for high‐rate click trains?

Abstract

Several studies have noted poor sensitivity to interaural time differences (ITD) among users of bilateral cochlear implants (CIs) compared to normal hearing listeners. One hypothesis for this impairment is that CI users are subject to a higher degree of binaural adaptation—a loss of sensitivity to binaural cues after onset—than normal hearing listeners, as a result of CI electrical stimulation. [Laback and Majdak, PNAS 15, 814–817 (2008)] demonstrated improved ITD discrimination in CI users by imposing random temporal jitter on CI pulse trains bilaterally. A candidate explanation for this improvement is that temporal jitter causes a “restarting” of the adapted binaural system, and, thus, improved sensitivity to ITD after onset. In the present study, temporal weighting functions of normal‐hearing listeners were measured for discrimination of ITD and interaural level differences carried by trains of 4000 Hz Gabor clicks. Interclick intervals of 1.25 and 2.5 s were tested with and without additional random temporal jitter. The results have implications for mechanisms of binaural adaptation as well as for binaural performance in CI users.