title: Assessment of nocturnal sleep architecture by actigraphy and one-channel electroencephalography in early infancy.
abstract: 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 3-4months. 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 6h 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 <10min or fed), and sleeping with strong signals (crying/fuss episodes≧10min). 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.
authors.affiliation: Department of Maternity Child Nursing, Akita Graduate School of Medicine and Faculty of Medicine, School of Health Science, Akita, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: Department of Maternity Child Nursing, Akita Graduate School of Medicine and Faculty of Medicine, School of Health Science, Akita, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Shinohara
authors.affiliation: Department of Maternity Child Nursing, Akita Graduate School of Medicine and Faculty of Medicine, School of Health Science, Akita, Japan. Electronic address: kodamah@hs.akita-u.ac.jp.
authors.forename: Hideya
authors.initials: H
authors.lastname: Kodama
mesh_terms: D056044:Actigraphy; D058256:Brain Waves; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009043:Motor Activity; D017440:Photoperiod; D012894:Sleep Stages / Q000502:physiology*
keywords: Actigraphy; Infants; Nocturnal sleep; One-channel electroencephalography; Sleeping through the night; Slow-wave sleep