Frequency discrimination and consonant recognition in the hearing impaired

Abstract

The frequency difference limen (DL) for short‐duration second‐formant transitions (F2) presented alone and in speechlike environments was examined in normal hearing and hearing‐impaired subjects. Four stimulus conditions were included: F2 transition alone; F2 transition in the presence of all formants (full formant); full‐formant stimuli preceded by a burst and followed by a vowel; and full‐formant stimuli preceded and followed by a vowel. For the simplest stimulus condition (F2 alone), all hearing‐impaired subjects had DLs within the 95% confidence interval around the mean of the normals. For all other conditions, however, the hearing impaired demonstrated extreme intersubject variation. Some hearing‐impaired subjects could not detect a formant transition of even 800 Hz, whereas others continued to perform like normal hearers. Consonant identification performance was also examined in CV and VCV environments. Consonants whose identification is believed to involve formant transitions were selected for study. In spite of modifications to the frequency discrimination task and use of relevant syllables, relatively weak correlations continue to be observed between F2 DL and consonant recognition ability, as well as between F2 DL and degree of hearing loss. [Work supported by NIH.]