Does selective attention influence the brain-stem auditory evoked potential?

We have re-examined the problem of selective attention in relation to brain-stem auditory evoked potentials (BAEPs). We compared BAEPs recorded in the relaxed individual with those elicited during visual attention and during auditory attention. Particular emphasis was placed on the use of a demanding visual task to ensure appropriately sustained levels of concentration by the subject for the durations of the tests. We measured the latency of wave I, the wave I-V interval and the amplitudes of waves I and V in 16 subjects in each of the conditions but could find no effect attributable to changes in states of attention. We conclude that there is no evidence for the actions of gating or switching mechanisms at early stages of the auditory pathways.