The effects of age and hearing impairment on the time course of backward masking

The present study was designed to assess the effects of age and hearing loss on the time course of backward masking. Thresholds for detecting a 10-ms, 500-Hz tone were measured as a function of the temporal separation between the signal and a 50-ms broadband masker in normal-hearing young listeners (18–25), normal-hearing older adults (65–82), and hearing-impaired older adults. Younger subjects exhibited less initial masking, had steeper recovery functions, and asymptoted closer to their unmasked thresholds than either group of older adults. Comparisons between the normal-hearing and hearing-impaired older individuals indicated a slower time course of recovery from backward masking for listeners with hearing loss. Differences between the two groups of normal-hearing listeners (young and old) suggest that age, independent of hearing loss, affects the temporal course of backward masking. Differences between the normal-hearing and hearing-impaired elderly listeners, however, indicate that age-related hearing impairment may also alter the rate of recovery from backward masking. [Work supported by the Brookdale Foundation and NIA.]