Effects of interstimulus interval on latency of the brainstem auditory evoked potential

Peak latency of the inferior collicular response (wave V) of the brainstem auditory evoked potential (BAEP) increases with decreasing interstimulus interval (ISI). The present research investigated relative peak shifts of major components of the BAEP in an attempt to identify the source of the observed shift in wave V. Peripheral as well as central transmission times (CTT) were computed for 9 young adults between an ISI of 100 msec and an ISI of 10 msec. The results indicate that shifts in wave V latency with changing ISI are due to a combination of central and peripheral processes. The magnitude of the shift observed for wave V was approximately 0.50 msec. This increase in latency was accounted for by an average 0.29 msec increase in peripheral transmission time, a 0.14 msec increase in CTT between waves I and III, and a 0.07 msec increase in CTT between waves III and V. The results suggest a dual process underlying latency changes in wave V of the BAEP as a function of decreasing ISI. These are peripheral adaptation or fatigue and central processes that may include short-term habituation.