ASA 126th Meeting Denver 1993 October 4-8

2aPP4. Modulation detection interference (MDI) for randomly fluctuating envelopes.

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

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

Modulation detection interference (MDI) was measured in normal-hearing listeners for stimuli with randomly fluctuating envelopes. The stimuli were generated by modulating pure-tone carriers by dc-shifted low-pass noises (cutoff=10 Hz). The target carrier was 1000 Hz and the interferer carrier 2250 Hz. The target could be presented either alone (baseline condition) or in conjunction with the interferer that was either gated synchronously with the target or was presented continuously. The interferer could be unmodulated, comodulated with the target, or modulated independently from the target. Results indicated substantial MDI in the presence of the interferer both for comodulated and independently modulated envelopes. The differential gating effects will be compared to those for sinusoidal amplitude modulations. [Work supported by the NIDCD R01-DC00418.]