Dead regions in the cochlea at 4 kHz in elderly adults: relation to absolute threshold, steepness of audiogram, and pure-tone average.

The aims of this study were (1) to investigate the prevalence of dead regions (DRs) at 4 kHz in elderly people with hearing loss and (2) to determine the extent to which the presence/absence of a DR can be predicted from the absolute threshold, the slope of the audiogram, or the pure-tone average (PTA) hearing loss at 0.5, 1, and 2 kHz. DRs were assessed for 98 ears with absolute thresholds between 60 and 85 dB HL at 4 kHz using the threshold equalizing noise test. Thirty-six ears had a DR at 4 kHz. There was no statistically significant difference in the slope of the audiogram or PTA between ears with and without DRs. However, the mean absolute threshold at 4 kHz was significantly higher for the group with DRs than for the group without DRs. The prevalence of DRs exceeded 50% for hearing losses greater than 70 dB.