ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2pPP18. Multiband detection of energy fluctuations.

J. H. Grose

J. W. Hall, III

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

The filtering properties of the ear permit the auditory periphery output to be viewed as a bank of parallel quasi-independent channels. The purpose of this study was to examine how information contained among the independent channels is combined. Four related experiments were undertaken in which the detection of an energy change within a channel was measured as a function of the number of channels carrying that change. Each experiment examined the detection of a different signal type: (1) The detection of multitone signals masked by narrow bands of noise; (2) the detection of intensity increments (intensity discrimination) for multiple noisebands; (3) the detection of intensity decrements for the same stimuli as (2); and (4) the detection of temporal gaps in multiple noisebands. Eight normal-hearing listeners participated and performance was measured for a 1-, 2-, 4-, and 8-channel stimulus. The center frequencies for the 8 channels were 356, 494, 663, 870, 1125, 1442, 1838, and 2338 Hz. For each signal type, performance improved with increasing number of channels carrying the signal. The comparative patterns of improvement will be discussed in terms of multiband detection models. [Work supported by the NIDCD R01-DC01507.]