Auditory brainstem responses to successive sounds: Effects of gap duration and depth

Abstract

Temporal acuity is the ability to differentiate between successive sounds based on temporal fluctuations in the waveform envelope. Psychophysically, human listeners can detect a gap as short as 2.5 ms between consecutive segments to encode the acoustical messages. The background noise diminishes the ability to follow fast variation between segments. In this study, we determined whether a physiological correlate of temporal acuity is also affected by the presence of noise. We recorded the auditory brainstem response (ABR) from human listeners using a harmonic complex followed by tone burst with the latter serving as the evoking stimulus. The duration and the depth of the silent gap between the harmonic complex and tone burst were manipulated. The latency of the ABR increased significantly as gap duration increased and gap depth decreased. No significant changes in amplitude were observed. These findings suggest that changing gap duration and depth affect the auditory system’s ability to encode successive sounds.