Maturational effects on the middle components of the averaged electroencephalic response.
Middle component AERs to brief click stimuli were recorded from 60 subjects in four age groups to assess age effects on waveform, latency, and amplitude. Replicable responses similar in waveform to those recorded in adults were observed in 3 - 4-year-old children, full-term newborns, and premature infants tested as early as the 31st postconceptional week. Latencies and amplitudes were compared across ages and significant age effects were evident for amplitude but not latency. Amplitudes of components Po, Pa and Pb were found to increase until 3 - 4 years of age and decline in adulthood. Response amplitudes for premature infants differed significantly from those of adults, but newborns' responses did not differ from either group. Only the responses of 3 - 4-year-old children were clearly differentiated from those of all other groups in this respect. Significant age effects on latency were found only for Po, which is postulated to be synonymous with Wave V of the brainstem response. The absence of a trend for decreasing latency as a function of age in the middle components is surprising in that both early (brainstem) and late (cortical) responses demonstrate this effect. This finding raises questions about the generator sources for middle components.
D000328:Adult; D000367:Age Factors; D001299:Audiometry; D001300:Audiometry, Evoked Response; D002648:Child; D006801:Humans; D007231:Infant, Newborn; D011930:Reaction Time