Identifying children with autism spectrum disorder at 18 months in a general population sample

Paediatr Perinat Epidemiol. 2014 May;28(3):255-62. doi: 10.1111/ppe.12114. Epub 2014 Feb 18.


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'.

Conclusion: 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.

Keywords: Autism Birth Cohort Study; M-CHAT; Norwegian Mother and Child Cohort Study; autism spectrum disorders; early identification; longitudinal studies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adult
  • Attention
  • Checklist*
  • Child Development Disorders, Pervasive / diagnosis*
  • Educational Status
  • Female
  • Humans
  • Infant
  • Longitudinal Studies
  • Male
  • Mass Screening / methods*
  • Maternal Age
  • Norway
  • Parents*
  • Play and Playthings
  • Sensitivity and Specificity
  • Social Behavior
  • Surveys and Questionnaires