Cochlear hearing loss and the processing of modulation: effects of temporal asynchrony.

Temporal coincidence and envelope correlation among components of a complex sound are informative cues for the perceptual organization of that sound. Listeners with hearing loss of cochlear origin often exhibit reductions in temporal processing of stimuli with randomly fluctuating envelopes. The purpose of this study was to examine the performance of such listeners on auditory grouping tasks which rely on temporal cues. The first experiment examined temporal asynchrony effects in a comodulation masking release (CMR) task. Performance was poorer than normal and appeared to be associated with reduced frequency selectivity. However, the pattern of asynchrony effects was the same as normal. The second experiment examined temporal asynchrony effects in a task based on envelope comparison interference. On this task, performance was similar to that for normal-hearing listeners. It was concluded that listeners with hearing loss of cochlear origin are comparable to normal-hearing listeners in their ability to make use of relatively gross temporal asynchrony cues.