Low-frequency vowel formant discrimination in hearing-impaired listeners.

Abstract

Measurements of vowel formant discrimination were made on 6 listeners with severe-to-profound sensorineural hearing losses and compared with discrimination in 4 normal listeners. The measure of discrimination was the size of the threshold for a frequency change in the formant of a synthetic vowel. An adaptive procedure was used to locate threshold. Results indicated that, at two low formant locations, 205 and 275 Hz, sensorineural discrimination was equal to normal; at 400 and 875 Hz, however, the sensorineural subjects had less discrimination than normal. Learning to maximum discrimination performance was slow for the sensorineural subjects at the two higher formant locations. Formant frequency discrimination appeared to be insensitive to changes in sensation level. Tactual discrimination tests with the vowel stimuli indicated that the obtained performance levels for very poor discrimination may have reflected tactual discrimination rather than auditory discrimination.