Place and temporal cues in pitch perception: are they truly independent?

Four adult users of the Mini System 22 cochlear implant participated in an experiment to investigate the perceptual independence of place-of-stimulation and temporal cues for pulsatile electrical stimulation. The motivation was the relatively poor rate discrimination ability of cochlear implantees compared to the higher accuracy of temporal coding revealed by electrophysiological measurements and the performance of normal hearing listeners. The hypothesis tested was that the central auditory system can combine consistent rate and place cues in a way that is more effective than using each cue independently. Difference limens for rate change, place change, and combined rate and place change (with consistent and inconsistent cues) were compared for stimulation at low and high rates. The results were compatible with place and rate cues being used independently in the combined rate- and place-change conditions, with no advantage found for the consistent-cue conditions.