Auditory brainstem responses in younger and older adults for broadband noises separated by a silent gap.

Wave V of the auditory brainstem response was measured to two 50-ms broadband noise bursts separated by silent gaps of varied duration (4, 8, 32, or 64 ms) for younger and older adults with normal hearing. All subjects had measurable wave V responses to the first noise burst. However, for the second noise burst, three of eight older adults did not have responses with gap durations of 4 and 8 ms, and one of eight younger adults did not have a measurable response with a gap duration of 4 ms. When responses were present for older adults, latencies were similar to those of younger subjects but amplitudes were smaller. These results suggest age-related deficits in gap detection at the level of the brainstem in a group of aged subjects with no threshold elevation. Results are similar to those of Boettcher et al. (1996) using an identical paradigm in young and aged Mongolian gerbils.