title: In school-age children who were born very preterm sleep efficiency is associated with cognitive function.
abstract: OBJECTIVE
  This study examined whether the association between sleep duration, as well as sleep continuity, and cognitive function differs between normally developing preterm children compared to full-term children during middle childhood.
  
  
  METHODS
  A total of 58 early preterm (<32 weeks' gestation) and 55 full-term children, aged 6-10 years and enrolled in elementary school, were assessed on sleep duration, sleep continuity and cognitive function. We used in-home polysomnographic recordings of total sleep time, sleep efficiency and nocturnal awakenings. Cognitive tests included intelligence, arithmetic, selective attention, verbal memory, and visuospatial memory.
  
  
  RESULTS
  Preterm children showed poorer performance in intelligence, arithmetic, selective attention, and visuospatial memory (d = 0.38-0.79, p < 0.05) and more objectively assessed nocturnal awakenings (d = 0.40, p = 0.03) than full-term children. Associations of sleep efficiency and cognitive functions (intelligence, arithmetic, selective attention, visuospatial memory) were positive and stronger for preterm children (β = 0.17-0.31, p < 0.05), while they were nonsignificant for full-term children.
  
  
  CONCLUSIONS
  Results confirm lower cognitive test scores and more nocturnal awakenings in normally developing early preterm children compared to full-term children. Furthermore, poor sleep efficiency may aggravate cognitive deficits, particularly in children who are more vulnerable due to premature birth.
authors.forename: Priska
authors.initials: P
authors.lastname: Hagmann-von Arx
authors.forename: Nadine
authors.initials: N
authors.lastname: Perkinson-Gloor
authors.forename: Serge
authors.initials: S
authors.lastname: Brand
authors.forename: Djana
authors.initials: D
authors.lastname: Albert
authors.forename: Edith
authors.initials: E
authors.lastname: Holsboer-Trachsler
authors.forename: Alexander
authors.initials: A
authors.lastname: Grob
authors.forename: Peter
authors.initials: P
authors.lastname: Weber
authors.forename: Sakari
authors.initials: S
authors.lastname: Lemola
mesh_terms: D001288:Attention; D002648:Child; D003071:Cognition; D002658:Developmental Disabilities / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007360:Intelligence; D008297:Male; D008568:Memory; D002666:Psychology, Child; D012890:Sleep