title: Distal-proximal skin temperature gradient prior to sleep onset in infants for clinical use.
abstract: BACKGROUND
  The objective of this study was to explore the possibility of using distal-proximal skin temperature gradient (DPG) to predict sleep-onset latency of night-time sleep for infants at home.
  
  
  METHODS
  Foot (for distal) and abdominal (for proximal) skin temperature during sleep onset in healthy infants, aged 4-9 months, was continuously recorded using a temperature logger at home. Sleep-onset latency during each study night was defined as the interval from lights-off to sleep onset, determined on actigraphy. Association of DPG profile after lights-off with sleep-onset latency on the study nights was evaluated.
  
  
  RESULTS
  Data for 43 nights from 28 infants were available for analysis. With regard to low DPG (<-2.5°C) at lights-off, >60% of infants fell asleep within 30 min if DPG was increased to ≥-2.5°C within 15 min after lights-off. If DPG remained at <-2.5°C at 15 min after lights-off, however, only 20% of infants fell asleep within 30 min. In addition, if infants were still awake at 15 min after lights-off and the DPG at that time was <-2.5°C, they were not likely to quickly fall asleep (predictive value was 0.875).
  
  
  CONCLUSIONS
  Increase in DPG by 15 min after lights-off is a key determinant for sleep-onset latency.
authors.affiliation: Japanese Red Cross Akita College of Nursing, Akita Graduate School of Medicine and Faculty of Medicine, School of Health Science, Akita, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Abe
authors.forename: Hideya
authors.initials: H
authors.lastname: Kodama
mesh_terms: D056044:Actigraphy / Q000379:methods; D002654:Child Care; D002675:Child, Preschool; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012881:Skin Temperature / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D013997:Time Factors
keywords: actigraphy; child care; circadian rhythm; skin temperature; sleep