Assessment of nocturnal sleep architecture by actigraphy and one-channel electroencephalography in early infancy

Objective: To elucidate characteristic sleep architecture of different nocturnal sleep patterns in early infancy. Methods: Participants were 27 infants at the same conceptional age of 3-4 months. Nocturnal sleep of these infants was monitored at home by simultaneously using actigraphy and a one-channel portable EEG device. According to the infants' activity for 6 h from sleep onset, each night's sleep pattern was classified into three categories: sleeping through the night (STN), sleeping with weak signals (crying/fuss episodes <10 min or fed), and sleeping with strong signals (crying/fuss episodes 10 min). Associations of sleep patterns with sleep variables (percentage of time in sleep stages, pattern of slow-wave sleep (SWS) recurrence, etc.) were investigated. Results: Analysis was conducted in 95 nights. STN pattern (n = 36) was characterized by suppressed body movements while EEG represented a state of wakefulness. Weak signal pattern (n = 27) tended to indicate rich and regular distributions of SWS across the night. Strong signal pattern (n = 32) was characterized by reduced sleep time, although the amount of SWS was not reduced to that degree. Exclusively breastfed infants accounted for 78% of weak signal patterns, whereas formula-feeding infants, 67% of STN patterns. In several nights with STN or strong signal pattern, SWS did not occur in >50% of the sleep cycles. Multiple regression analysis showed that exclusive breastfeeding may increase the proportion of SWS in non-REM sleep. Conclusions: Each nocturnal sleep pattern was associated with some sleep architecture, part of which would be attributed to infant's feeding methods. (C) 2015 Elsevier Ireland Ltd. All rights reserved.