title: Movement distribution: a new measure of sleep fragmentation in children with upper airway obstruction.
abstract: OBJECTIVE
  To develop a measure of sleep fragmentation in children with upper airway obstruction based on survival curve analysis of sleep continuity.
  
  
  METHODS
  Prospective repeated measures.
  
  
  METHODS
  Hospital sleep laboratory.
  
  
  METHODS
  92 children aged 3.0 to 12.9 years undergoing 2 overnight polysomnographic (PSG) sleep studies, 6 months apart. Subjects were divided into 3 groups based on their obstructive apnea and hypopnea index (OAHI) and other upper airway obstruction (UAO) symptoms: primary snorers (PS; n = 24, OAHI <1), those with obstructive sleep apnea syndrome (OSAS; n = 20, OAHI ≥1) and non-snoring controls (C; n = 48, OAHI <1).
  
  
  METHODS
  Subjects in the PS and OSAS groups underwent tonsillectomy and adenoidectomy between PSG assessments.
  
  
  RESULTS
  Post hoc measures of movement and contiguous sleep epochs were exported and analyzed using Kaplan-Meier estimates of survival to generate survival curves for the 3 groups. Statistically significant differences were found between these group curves for sleep continuity (P < 0.05) when using movement events as the sleep fragmenting event, but not if stage 1 NREM sleep or awakenings were used.
  
  
  CONCLUSIONS
  Using conventional indices of sleep fragmentation in survival curve analysis of sleep continuity does not provide a useful measure of sleep fragmentation in children with upper airway obstruction. However, when sleep continuity is defined as the time between gross body movements, a potentially useful clinical measure is produced.
authors.affiliation: School of Medical Sciences, University of Adelaide, Adelaide, Australia: Department of Respiratory and Sleep Medicine, Children, Youth and Women's Health Service, North Adelaide, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Coussens
authors.affiliation: Cardiovascular Research Centre, Royal Adelaide Hospital and School of Medicine, University of Adelaide, Adelaide, Australia: Children's Research Centre, University of Adelaide, Adelaide, Australia.
authors.forename: Mathias
authors.initials: M
authors.lastname: Baumert
authors.affiliation: Children's Research Centre, University of Adelaide, Adelaide, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Kohler
authors.affiliation: Department of Respiratory and Sleep Medicine, Children, Youth and Women's Health Service, North Adelaide, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Martin
authors.affiliation: Department of Respiratory and Sleep Medicine, Children, Youth and Women's Health Service, North Adelaide, Australia: Children's Research Centre, University of Adelaide, Adelaide, Australia.
authors.forename: Declan
authors.initials: D
authors.lastname: Kennedy
authors.affiliation: School of Psychology, University of South Australia, Adelaide, Australia.
authors.forename: Kurt
authors.initials: K
authors.lastname: Lushington
authors.affiliation: School of Medical Sciences, University of Adelaide, Adelaide, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Saint
authors.affiliation: Department of Respiratory and Sleep Medicine, Children, Youth and Women's Health Service, North Adelaide, Australia.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Pamula
mesh_terms: D000233:Adenoidectomy; D000402:Airway Obstruction / Q000150:complications / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D009068:Movement / Q000502:physiology*; D017286:Polysomnography; D011446:Prospective Studies; D012890:Sleep / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology*; D012892:Sleep Deprivation / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology; D012913:Snoring / Q000150:complications* / Q000503:physiopathology; D014068:Tonsillectomy; D014851:Wakefulness / Q000502:physiology
keywords: children; movement; sleep continuity; sleep fragmentation; upper airway obstruction