Shared monaural and binaural temporal processing limits in bilateral cochlear implant listeners

• Published in: The Journal of the Acoustical Society of America 2016-04, Vol.139 (4), p.2210-2210
• Main Authors: Ihlefeld, Antje, Carlyon, Robert P., Kan, Alan, Churchill, Tyler H., Litovsky, Ruth Y.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4950602

Bilaterally implanted cochlear implant users were tested on monaural rate discrimination and binaural interaural time difference (ITD) discrimination, as a function of pulse rate, to examine the hypothesis that deterioration in performance at high rates occurs for the two tasks due to a common neural basis. For the rate discrimination task, pulse trains were presented to one electrode, located in the apical, middle, or basal part of the array, and in either the left or the right ear. In each two-interval trial, the standard stimulus had a rate of 100, 200, 300, or 500 pulses-per-second and the signal stimulus had a rate 35% higher. For the ITD discrimination task, performance between pitch-matched electrode pairs was measured for the same standard rates as in the rate discrimination task, and with an ITD of + /− 500 µs. Sensitivity (d′) on both tasks decreased with increasing rate. Results show that ITD scores for different pairs of electrodes correlated with the lower of the rate discrimination scores for those two electrodes. Statistical analysis, which partialed out overall differences between listeners, electrodes, and rates, supports the hypothesis that monaural and binaural temporal processing limitations are at least partly due to a common mechanism.