Evaluation of auditory enhancement and auditory suppression in listeners with normal hearing and reduced speech recognition in noise.

A number of individuals complain of difficulties with speech recognition in noise in spite of normal hearing. This has prompted a search for disruptions in other areas of auditory processing that may account for these deficits. Two processes that may be related to speech recognition, auditory suppression and auditory enhancement, were evaluated in five listeners with normal speech recognition in noise (NSRN) and five listeners with reduced speech recognition in noise (RSRN). Although differences between the two groups were not observed for enhanced forward masking, significant differences were observed in two-tone suppression when the duration of the suppressor was varied. Those with RSRN showed greater suppression than those with NSRN when the suppressor onset preceded the masker onset.