title: Early Childhood Sleep Patterns and Cognitive Development at Age 6 Years: The Generation R Study.
abstract: To explore the association of sleep duration and awakening frequency with cognitive outcomes in young children.
  
  
  
  Mothers of 2,800 children from the Generation R cohort reported sleep duration and awakenings at children's age 24 months. At age 6 years, validated Dutch measures were used to assess children's nonverbal intelligence and language comprehension.
  
  
  
  We found a nonlinear association of total sleep time at 24 months with nonverbal intelligence ( p  = 0.03) and language comprehension ( p  = 0.04) at 6 years. Toddlers sleeping within the recommended 11-14 hr had more favorable cognitive development compared with both extremes. Frequent awakenings were negatively associated with nonverbal intelligence, but not with verbal comprehension.
  
  
  
  Sleep duration in toddlerhood has an inverted-U-shaped relation with childhood cognitive measures. Frequent awakenings are associated with lower nonverbal intelligence. Given the marked decline in sleep duration and awakenings in toddlerhood, developmental changes of sleep patterns might be important for cognitive development.
authors.affiliation: Generation R Study Group, Erasmus University Medical Center, Rotterdam, Netherlands.|Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, Netherlands.
authors.forename: Desana
authors.initials: D
authors.lastname: Kocevska
authors.affiliation: Generation R Study Group, Erasmus University Medical Center, Rotterdam, Netherlands.|Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, Netherlands.
authors.forename: Jolien
authors.initials: J
authors.lastname: Rijlaarsdam
authors.affiliation: Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, Netherlands.
authors.forename: Akhgar
authors.initials: A
authors.lastname: Ghassabian
authors.affiliation: Generation R Study Group, Erasmus University Medical Center, Rotterdam, Netherlands.|Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands|Department of Pediatrics, Sophia Children's Hospital, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Vincent W
authors.initials: VW
authors.lastname: Jaddoe
authors.affiliation: Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Franco
authors.affiliation: Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, Netherlands.
authors.forename: Frank C
authors.initials: FC
authors.lastname: Verhulst
authors.affiliation: Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands|Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, Netherlands.|Department of Psychiatry, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Henning
authors.initials: H
authors.lastname: Tiemeier
mesh_terms: D002648:Child; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007361:Intelligence Tests / Q000706:statistics & numerical data; D008297:Male; D012890:Sleep / Q000502:physiology*; D013995:Time
keywords: IQ; awakenings; development; language; sleep duration