The effect of flanking bands on sensitivity to interaural time differences.

Abstract

We are examining the potential for cochlear implant patients who retain some low‐frequency residual hearing in both ears to benefit from interaural time differences (ITDs) to improve speech reception. Given the likelihood of asymmetrical loss in the low‐frequency region, the relationship between spectral overlap and ITD sensitivity is of interest. We previously measured ITD sensitivity using narrow‐band noise carriers, while varying the amount of spectral overlap between the ears. We found very good sensitivity when the bands completely overlapped, but for most listeners, sensitivity declined as the center frequency of one band was moved away from the other. When, for example, 2/3‐octave bands were offset by 1/3 octave and presented to each ear, ITD sensitivity declined. This condition consists of three bands, a 1/3‐octave center band that is spectrally similar across ears, and two 1/3‐octave flanking bands, each of which is present in one or the other ear. Because the center band alone produces good ITD ...