ASA 126th Meeting Denver 1993 October 4-8

3aPP5. Stream segregation in normal-hearing and cochlear-impaired listeners.

J. H. Grose J. W. Hall L. Mendoza

Div. Otolaryngol./Head & Neck Surgery, Univ. North Carolina, Chapel Hill, NC 27599-7070

Cochlear-impaired and normal-hearing listeners were compared on two tasks intended to assess auditory stream segregation. One task measured gap discrimination between two tones that were presented either in isolation or were embedded into a sequential stream of tones. For tone pairs distally spaced in frequency, performance was poor when the tones were presented in isolation but improved when they were drawn into separate auditory streams, presumably because temporal judgments could now be made within a stream. Both groups of listeners gave similar patterns of results although some differences were apparent. The second task was a melody recognition procedure [J. A. P. M. de Laat and R. Plomp, J. Acoust. Soc. Am. 78, 1574--1577 (1985)] and involved identifying a 4-note target melody embedded between two competing melodies as a function of the proximity and temporal synchrony of the competing melodies. In both groups, marked individual differences were observed. Results from both tasks will be discussed in terms of the effects of cochlear impairment on auditory grouping skills. [Work supported by the NIDCD R01-DC01507.]