The effects of aging on the stapedius reflex thresholds.

The acoustic reflex thresholds for broadband noise and 500-, 1000-, and 2000-Hz activating signals were measured in a group of young normal hearing adults and a group of elderly normal hearing subjects. The results indicated that the acoustic reflex thresholds for tonal activating signals in the young subjects were similar to those in the elderly subjects. However, the acoustic stapedius reflex thresholds for broadband noise activating signals is significantly higher in the elderly subjects than in the young. These differences were explained in light of Bredburg's findings [Acta Otolaryngol. Suppl. 236, 1--135 (1968)] regarding degeneration of outer hair cells as a function of aging.