Degradations in frequency and temporal resolution with age and their impact on speech identification.

Measures of frequency resolution were obtained in two population samples. The first sample comprised 1764 subjects with various degrees of sensorineural hearing impairment aged from 17 to 80 years. The second sample included 229 subjects with ages between 50 and 75 years, balanced to avoid confounding the effects of impairment and age. Subjects in the second sample were also assessed using a gap-detection measure of temporal resolution and a test of speech identification using sentences in noise. In both samples, frequency resolution ability declined progressively with increasing hearing threshold level (HTL). After accounting for the effects of HTL, there was a minor dependence of frequency resolution on age, older subjects having poorer frequency resolution. Temporal resolution deteriorated with HTL but not with age. The speech identification scores could be predicted from HTL at 2 and 8 kHz and age. Frequency resolution was not a factor. Temporal resolution was only a factor when subjects with extremely poor temporal resolution were included.