Effect of noise masking on the brain-stem and middle-latency auditory evoked potentials: central and peripheral components.

Brain-stem (BAEP) and middle-latency (MLAEP) auditory evoked potentials were recorded in zero noise and in 3 levels of continuous ipsilateral broadband noise. New information is presented on the effects of noise on BAEP wave I. Latency of wave I was not changed by increasing noise, but wave V latency linearly increased. Amplitude of waves I and V decreased non-linearly. The amplitude decrease was equivalent for both waves and occurred only at the higher noise levels. The dissociation of latency effects for waves I and V indicates a central component for the effect of noise on latency. The parallel amplitude change for waves I and V suggests a largely peripheral component. The MLAEP Pa latency also increased with increasing noise further supporting a central mechanism.