ASA 124th Meeting New Orleans 1992 October

3aPP6. Temporal resolution for frequency gliding signals and its relation to the phonemic perception of /b/ and /w/.

J. F. MacNeil

E. B. Slawinski

Dept. of Physchol., Univ. of Calgary, 2500 University Dr., Calgary, AB T2N 1N4, Canada

The effects of age and hearing loss on amplitude and temporal resolution were examined. The first experiment assessed the perception of the phonemic distinction between three continua of /b/ and /w/ stimuli which varied in their amplitude envelopes. The degree of hearing impairment significantly effected the importance of the type of acoustical cue with hearing impaired listeners demonstrating a greater influence of the amplitude envelope and a shift in the phonemic boundary toward longer transition durations relative to normal listeners. The second experiment examined duration discrimination in a 2AFC task using a constant stimuli method for isolated analogs of the second formant transitions. Thresholds were interpolated from the 75% correct position from probits fitted to the psychometric function. The effects of both age and hearing status were significant, however the type of hearing impairment (shallow or steeply sloping) was an important factor in temporal resolution. Additionally, among listeners with normal hearing within the frequency range being tested elderly adults showed poorer temporal resolution relative to young adults.