ASA 124th Meeting New Orleans 1992 October

1aPP4. Masking level differences for tones and speech in elderly listeners with relatively normal audiograms.

E. A. Poth

J. H. Grose

Div. of Otolaryngology/Head & Neck Surgery, Univ. of North Carolina, Chapel Hill, NC 27599

Masking level differences (MLDs) were measured for both tones and speech in a group of elderly listeners with normal, or near-normal, audiometric sensitivity. The tonal MLD was obtained for the detection of a 500-Hz tone masked by a 100-Hz wide band of noise centered at 500 Hz. The speech MLD was obtained for the recognition of spondaic words masked by speech-shaped noise. For both types of stimuli, the MLDs measured in the elderly listeners were significantly smaller than those measured in a control group of normal-hearing young listeners. This reduction was primarily due to an elevation of the NoS(pi) thresholds in the elderly group. The results support the hypothesis that a reduced binaural advantage may contribute to the difficulty of understanding speech in noise reported by the elderly listeners. Furthermore, the use of listeners with normal, or near-normal, audiometric sensitivity suggests that factors other than peripheral sensitivity loss may play a role in speech understanding in noisy listening conditions. [Research supported by NIDCD and the Andrus Foundation.]