Emerging cognitive profiles in high-risk infants with and without autism spectrum disorder

Abstract

This paper examined early developmental trajectories in a large, longitudinal sample at high-risk for ASD ('HR') and low-risk ('LR') controls, and the association of trajectories with 3-year diagnosis. Developmental assessments were conducted at 6, 12, 24 months, and 3 years, with blinded "clinical best-estimate" expert diagnosis at age 3. HR infants were enrolled based only on familial risk. LR infants, from community sources, had no first- or second-degree ASD relatives. All infants were born at 36-42 weeks, weighing ≥2500 g, with no identifiable neurological, genetic, or severe sensory/motor disorders. Analytic phase I: semi-parametric group-based modeling to identify distinct developmental trajectories (n = 680; 487 HR; 193 LR); phase II: Trajectory membership in relation to 3-year diagnosis (n = 424; 310 HR; 114 LR). Three distinct trajectories emerged (1) inclining; (2) stable-average; (3) declining; trajectory membership predicted diagnosis (χ2 = 99.40; p