Measure and model of vocal-tract length discrimination in cochlear implants

Voice discrimination is crucial to selectively listen to a particular talker in a crowded environment. In normalhearing listeners, it strongly relies on the perception of two dimensions: the fundamental frequency and the vocal-tract length. Yet, very little is known about the perception of the latter in cochlear implants. The present study reports discrimination thresholds for vocal-tract length in normal-hearing listeners and cochlear-implant users. The behavioral results were then used to determine the effective spectral resolution in a model of electric hearing: effective resolution in the implant was found to be poorer than previously suggested by psychophysical measurements. Such a model could be used for clinical purposes, or to facilitate the development of new strategies.