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

2pPP17. Gating effects in CMR.

J. W. Hall, III

J. H. Grose

D. R. Hatch

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

CMR is sometimes smaller for gated than continuous maskers. Our current work on CMR for multiple, comodulated narrow noise bands indicates that the gating effect is minimized when the number of comodulated bands is large. The present study extends this work to the CMR paradigm where pure tone signal thresholds are obtained as function of modulated and unmodulated noise bandwidth. Results indicate that in unmodulated noise, gated and continuous thresholds do not differ, regardless of noise bandwidth. In modulated noise, thresholds are often higher for gated noise than continuous noise when noise bandwidth is narrow, but not when the noise bandwidth is considerably wider than the auditory filter bandwidth. These results may suggest that gating effects on CMR are generally small when comodulation information is available across a large number of auditory channels. Results will be discussed in terms of competing cues for auditory grouping. [Research supported by AFOSR.]