title: Developmental trajectories in children with and without autism spectrum disorders: the first 3 years.
abstract: Retrospective studies indicate 2 major classes of autism spectrum disorder (ASD) onset: early and later, after a period of relatively healthy development. This prospective, longitudinal study examined social, language, and motor trajectories in 235 children with and without a sibling with autism, ages 6-36 months. Children were grouped as: ASD identified by 14 months, ASD identified after 14 months, and no ASD. Despite groups' initial similar developmental level at 6 months, ASD groups exhibited atypical trajectories thereafter. Impairment from 14 to 24 months was greater in the Early-ASD than the Later-ASD group, but comparable at 36 months. Developmental plateau and regression occurred in some children with ASD, regardless of timing of ASD diagnosis. Findings indicate a preclinical phase of varying duration for ASD.
authors.affiliation: Kennedy Krieger Institute, Baltimore, MD 21211, USA. landa@kennedykrieger.org
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Landa
authors.forename: Alden L
authors.initials: AL
authors.lastname: Gross
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stuart
authors.forename: Ashley
authors.initials: A
authors.lastname: Faherty
mesh_terms: D002657:Child Development / Q000502:physiology*; D002659:Child Development Disorders, Pervasive / Q000503:physiopathology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007802:Language; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D011446:Prospective Studies; D011581:Psychological Tests; D035781:Siblings; D012919:Social Behavior; D013997:Time Factors