Sensitivity to spectral and temporal cues in music with a cochlear implant in single-sided deaf listeners

Despite the poor sound quality with the cochlear implant (CI), single-sided deaf (SSD) CI users often prefer to listen to music with binaurally combined acoustic and electric hearing. The source of this binaural benefit is unclear. Is the benefit due to gross binaural restoration or synchronous temporal envelope information across ears? Does the detail of the spectral and/or temporal content in the CI ear matter? We investigated sources of binaural benefit for music quality in SSD-CI users by manipulating the input to the CI. Unprocessed music was presented to the acoustic-hearing ear. Experimental stimuli were delivered directly to the CI ear: unprocessed (same as everyday listening), reduced temporal modulations (using a sinewave vocoder to restrict the input to the CI), reduced spectral information (wideband noise modulated by the music temporal envelope), or wideband noise. Preliminary results suggest sensitivity to the spectral and temporal information delivered to the CI ear; however, this sensitivity was highly variable across participants. Binaural benefits were not observed when only temporal cues or white noise were presented to the CI ear. Manipulation of vocoders presented to the CI ear may be a promising approach to evaluate perception of spectral and temporal cues with the CI.