Perceptual mechanism for spectral‐ripple discrimination in cochlear implant listeners: Behavioral and model data.

The present study investigated the perceptual mechanism for spectral‐ripple discrimination in cochlear implant listeners. The main goal of this study was to determine whether cochlear implant listeners use a local intensity cue or global spectral shape for spectral‐ripple discrimination. The effect of channel interaction on spectral‐ripple discrimination was also evaluated. Results showed that it is unlikely that cochlear implant listeners depend on a local intensity cue for robust spectral‐ripple discrimination. A phenomenological model of spectral‐ripple discrimination, as an ideal observer, showed that a perceptual mechanism based on discrimination of a single intensity difference cannot account for performance of cochlear implant listeners. Instead, there was a significant dependence of thresholds on spectral modulation depth and channel interaction. The evidence supports the hypothesis that spectral‐ripple discrimination involves integrating information from multiple channels. [Work supported by NIH ...