Rate and Filter Dependence of the Middle-Latency Response in Infants

Abstract

Auditory evoked-potential activity in the 0 to 100-ms latency range was explored using wide-band filtering and a range of stimulus rates, in 8 babies ranging in age from 2 to 6 months. We observed both a stable early positive peak, in the 10 to 15-ms region, and a rate-dependent, positive peak at about 50 ms in all 8 babies. The latter response was best observed at rates of 1-2.5 stimuli/s and seldom observed at rates above 4/s. This peak may represent a developmentally early version of the Pa peak of the adult middle-latency response.