The auditory evoked response in babies during REM sleep

Abstract

1. 1. The auditory averaged evoked response (AER) was measured at the vertex in twelve 6–12-month-old normal babies during Stage 2 and rapid eye movement (REM) sleep and during the ocular quiescent and eye movement burst phases of REM sleep. Amplitudes and latencies of wave N 2 of the auditory AER were compared during the different sleep stages and to previously reported values for normal and autistic children. 2. 2. The latencies of wave N 2 in the babies were similar to those of the normal children during Stage 2. However, latencies during REM sleep and during both the eye movement burst and ocular quiescent epochs of REM sleep were significantly longer in the babies. 3. 3. The babies showed a tendency toward greater amplitudes of wave N 2 during both the eye movement burst and ocular quiescent phases of REM sleep than during Stage 2 sleep. In the group of babies, the relative amplitudes of wave N 2 during both REM sleep and the eye movement bursts of REM sleep (relative to Stage 2 sleep) were significantly greater than in a group of normal children, but were similar to those of a group of young autistic children. 4. 4. These findings suggest that the normal phasic inhibition of evoked responses accompanying the ocular activity of REM sleep may not be present in the very young organism and that the development of phasic inhibition may be related to maturational factors underlying the post-natal reduction of REM sleep time.