title: Activity-based assessment of the sleep behaviors of VLBW preterm infants and full-term infants at around 12 months of age.
abstract: OBJECTIVE
  The aim of this study is to identify the characteristics of sleep behaviors assessed from activity data among very low-birth weight (VLBW) preterm infants in comparison to full-term infants at the age of around 12 corrected months, due to the possibility that sleep behaviors of preterm infants may be different from those of full-term infants.
  
  
  METHODS
  Cross-sectional study. Infant sleep measures were obtained through actigraphs (Micro-mini RC, Ambulatory Monitoring Inc., Ardsley, NY), which were attached to the infants' ankles during a week-long period. The subjects were 14 preterm infants and 14 full-term infants in which the mean ages were 13.3+/-2.1 corrected months and 12.3+/-2.4 month, respectively.
  
  
  RESULTS
  Preterm infants showed significantly less sleep duration during nighttime than full-term infants. The mean activity score and ACTX (Activity Index: percentage minutes with more than 0 activity score) of preterm infants during nighttime were significantly higher than those of full-term infants. No significant differences in total sleep duration, daytime sleep duration, the number of night-wakings, and sleep efficiency were found between the two groups.
  
  
  CONCLUSIONS
  Preterm infants slept less and had a larger percentage of less restful sleep during nighttime. The results indicated that prematurity at the time of birth remained throughout the developmental course of sleep behaviors among preterm infants at around the age of 12 corrected months.
authors.affiliation: Kobe University Graduate School of Health Sciences, Japan. asaka@konan-wu.ac.jp
authors.forename: Yoko
authors.initials: Y
authors.lastname: Asaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takada
mesh_terms: D000375:Aging / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D018730:Infant Behavior / Q000502:physiology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000502:physiology*; D008297:Male; D018670:Monitoring, Ambulatory; D009043:Motor Activity / Q000502:physiology*; D011247:Pregnancy; D012890:Sleep / Q000502:physiology*