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.]