ASA 127th Meeting M.I.T. 1994 June 6-10

5aPP17. Frequency glide discrimination in the F2 region by normal-hearing and hearing-impaired listeners.

Van Summers

Majorie R. Leek

Army Audiol. and Speech Ctr., Walter Reed Army Med. Ctr., Washington, DC 20307-5001

Several researchers have suggested that the dynamic formant transitions present within consonant--vowel and vowel--consonant utterances may be poorly processed by hearing-impaired (HI) listeners. To investigate HI listeners' processing of transitional stimuli, six HI and six normal-hearing (NH) listeners were asked to discriminate between frequency glides patterned after second formant transitions in English CV syllables. The influence of glide duration, rate, and frequency extent were examined for each group in quiet and in 35-dB spectrum level broadband noise. Glide rate did not show a significant direct effect on frequency difference limens (DLs) for glide onset. Reductions in glide duration and the presence of noise each led to significant increases in DLs. The magnitudes of these effects were similar across groups. The only significant group differences were observed for gradual glides of limited frequency extent. This finding is consistent with more accurate processing of ``cochlear dispersion'' cues on the part of NH listeners [Porter et al., J. Acoust. Soc. Am. 90, 1298--1308 (1991)]. [Work supported by NIDCD.]