Factors affecting vowel identification in hearing-impaired listeners

Abstract

Vowel identification generally poses little difficulty for listeners with mild to moderate hearing impairment despite evidence for poorer frequency resolution compared to normal-hearing listeners. Normal-hearing listeners use formant movement and duration cues as well as spectral target cues to identify vowels. This study examines use of formant movement and duration cues by hearing-impaired listeners. Sets of very natural-sounding vowel stimuli with and without formant movement cues (dynamic and static) and with and without duration cues (appropriate and fixed) were made with a new speech resynthesis technique [H. Kawahara, Proc. ICASSP, 1–4 (1997)] using vowels produced by male and female talkers in /dVd/ context. Two groups of young normal-hearing listeners, one with simulated hearing loss typical of 70 year-old males and one control group, displayed no difference in overall vowel identification scores. Both groups obtained significant benefit from tokens containing formant movement cues. Duration was not as effective a cue for vowel identification as formant movement. Results for elderly hearing-impaired and elderly normal-hearing listeners will be presented, and the impact of talker variability upon vowel identification will be discussed. [Work supported by NIH-NIDCD 02229.]