DEVELOPMENT OF CONSOLIDATED SLEEP AND WAKEFUL PERIODS IN RELATION TO THE DAV/NIGHT CYCLE IN INFANCY

Abstract

Periods of sustained sleep were analyzed to assess the development of sleep-state organization and structure during the first 6 mo. of life. Infants first establish consolidated sleep and wakeful periods, which then become oriented to the 24-h day/night cycle. As infants mature they gradually show greater sleep efficiency, and at onset of sleep. REM [rapid eye movement] periods become less likely. The longest sleep period progressively becomes associated with the dark period of the 24-h cycle. This study also assessed the sequences of NREM[non-REM]-REM sleep-cycle organization during the first 6 mo. of life. Atlhough individual infants may have a significant correlation between duration of sleep and latency at onset of sleep, the over-all direction is not constant, nor is an age effect apparent during the first 6 mo. States of alertness, which develop independently in the perinatal period, become integrated in early infancy.