Presbyacusis

Abstract

The effect of age on discrimination of filtered speech was studied with two different frequency bands using the monaural test and Matzker's binaural test. The intelligibility of filtered speech fell very early as a function of age. In the binaural test deterioration was noted in the group 30–39 years, taking the group 20–29 years as basis of reference. The change in intelligibility occurred before any changes appeared in pure tone thresholds in the frequency area of the filtered speech test. After 60 years, a significant asymmetry appeared in discrimination of filtered speech. Intelligibility was better in the binaural test and the monaural test of the left ears than in the right ears. This difference was attributed to the effect of cerebral dominance becoming evident in the degenerated central auditory pathways. Under 60 years of age the compensatory mechanism of the centrencephalic system apparently prevents the effect of cerebral dominance in filtered speech test.

Notes

This study was supported by a grant from the National Council for Medical Sciences.