Abstract:
Listeners with sensorineural hearing loss often have difficulty in discriminating stop consonants even when the speech signals are presented at high levels. One hypothesis offered to explain their deficit is that they cannot use the information contained in the rapid formant transitions as well as normal-hearing listeners. Sets of three CV syllables were synthesized corresponding to /ba, da, ga/ with formant transitions for each set ranging from 5 to 160 ms in duration. The listener's task was to identify the presented consonant in a three-alternative, closed-set response task. The results for normal-hearing listeners showed nearly perfect performance for transitions of 20 ms and longer, whereas the shortest transitions yielded poorer performance. The hearing-impaired listeners showed large deficits compared to the normals for the longer duration transitions only, for shorter durations their performance was slightly less than, and sometimes equal to that of normals. These results would appear to contradict the original hypothesis, and supports recent psychoacoustic results of Summers and Leek [J. Acoust. Soc. Am. 97, 3825--3832 (1995)]. Therefore, increasing the duration of formant transitions for hearing-impaired listeners is not a helpful solution to their difficulties. [Work supported by NIDCD Grant DC 00377.]