title: Validating actigraphy as a measure of sleep for preschool children.
abstract: OBJECTIVE
  The algorithms used to derive sleep variables from actigraphy were developed with adults. Because children change position during sleep more often than adults, algorithms may detect wakefulness when the child is actually sleeping (false negative). This study compares the validity of three algorithms for detecting sleep with actigraphy by comparing them to PSG in preschoolers. The putative influence of device location (wrist or ankle) is also examined.
  
  
  METHODS
  Twelve children aged 2 to 5 years simultaneously wore an actigraph on an ankle and a wrist (Actiwatch-L, Mini-Mitter/Respironics) during a night of PSG recording at home. Three algorithms were tested: one recommended for adults and two designed to decrease false negative detection of sleep in children.
  
  
  RESULTS
  Actigraphy generally showed good sensitivity (> 95%; PSG sleep detection) but low specificity (± 50%; PSG wake detection). Intraclass correlations between PSG and actigraphy variables were strong (> 0.80) for sleep latency, sleep duration, and sleep efficiency, but weak for number of awakenings (< 0.40). The two algorithms designed for children enhanced the validity of actigraphy in preschoolers and increased the proportion of actigraphy-scored wake epochs scored that were also PSG-identified as wake. Sleep variables derived from the ankle and wrist were not statistically different.
  
  
  CONCLUSIONS
  Despite the weak detection of wakefulness, Acti-watch-L appears to be a useful instrument for assessing sleep in preschoolers when used with an adapted algorithm.
authors.affiliation: Department of Psychology, Université de Montréal, Canada.
authors.forename: Marie-Ève
authors.initials: MÈ
authors.lastname: Bélanger
authors.forename: Annie
authors.initials: A
authors.lastname: Bernier
authors.forename: Jean
authors.initials: J
authors.lastname: Paquet
authors.forename: Valérie
authors.initials: V
authors.lastname: Simard
authors.forename: Julie
authors.initials: J
authors.lastname: Carrier
mesh_terms: D056044:Actigraphy / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D000465:Algorithms; D000704:Analysis of Variance; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*
keywords: Actigraphy; children; polysomnography; validation