title: Identifying children with autism spectrum disorder at 18 months in a general population sample.
abstract: BACKGROUND
  Previous research on clinical and high-risk samples suggests that signs of autism spectrum disorder (ASD) can be detected between 1 and 2 years of age. We investigated signs of ASD at 18 months in a population-based sample and the association with later ASD diagnosis.
  
  
  METHODS
  The study sample includes 52,026 children born 2003 through 2008 and is a subset of children that participated in the Norwegian Mother and Child Cohort (MoBa), a population-based longitudinal study, and the Autism Birth Cohort (ABC), a sub-study on ASD. Parents completed all 23 items from the Modified Checklist for Autism in Toddlers (M-CHAT) at 18 months.
  
  
  RESULTS
  The M-CHAT 6-critical-item criterion and the 23-item criterion had a specificity of 97.9% and 92.7% and a sensitivity of 20.8% and 34.1%, respectively. In the 173 children diagnosed with ASD to date, 60 children (34.7%) scored above the cut-off on either of the screening criteria. The items with the highest likelihood ratios were 'interest in other children', 'show objects to others' and 'response to name'.
  
  
  CONCLUSIONS
  Even though one-third of the children who later received an ASD diagnosis were identified through M-CHAT items, the majority scored below cut-off on the screening criteria at 18 months. The results imply that it might not be possible to detect all children with ASD at this age.
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Nina
authors.initials: N
authors.lastname: Stenberg
authors.forename: Michaeline
authors.initials: M
authors.lastname: Bresnahan
authors.forename: Nina
authors.initials: N
authors.lastname: Gunnes
authors.forename: Deborah
authors.initials: D
authors.lastname: Hirtz
authors.forename: Mady
authors.initials: M
authors.lastname: Hornig
authors.forename: Kari Kveim
authors.initials: KK
authors.lastname: Lie
authors.forename: W Ian
authors.initials: WI
authors.lastname: Lipkin
authors.forename: Catherine
authors.initials: C
authors.lastname: Lord
authors.forename: Per
authors.initials: P
authors.lastname: Magnus
authors.forename: Ted
authors.initials: T
authors.lastname: Reichborn-Kjennerud
authors.forename: Synnve
authors.initials: S
authors.lastname: Schjølberg
authors.forename: Pål
authors.initials: P
authors.lastname: Surén
authors.forename: Ezra
authors.initials: E
authors.lastname: Susser
authors.forename: Britt Kveim
authors.initials: BK
authors.lastname: Svendsen
authors.forename: Stephen
authors.initials: S
authors.lastname: von Tetzchner
authors.forename: Anne-Siri
authors.initials: AS
authors.lastname: Oyen
authors.forename: Camilla
authors.initials: C
authors.lastname: Stoltenberg
mesh_terms: D000328:Adult; D001288:Attention; D057189:Checklist; D002659:Child Development Disorders, Pervasive / Q000175:diagnosis*; D004522:Educational Status; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008423:Maternal Age; D009664:Norway; D010290:Parents; D010988:Play and Playthings; D012680:Sensitivity and Specificity; D012919:Social Behavior; D011795:Surveys and Questionnaires
keywords: Autism Birth Cohort Study; M-CHAT; Norwegian Mother and Child Cohort Study; autism spectrum disorders; early identification; longitudinal studies