Studies estimate that 30% of individuals with autism are minimally verbal. Understanding what factors predict longer‐term expressive development in children with language delays is critical to inform identification and treatment of those at‐risk for persistent language impairments. The present study examined predictors of expressive language development in language‐delayed preschoolers followed through later school‐age and young adulthood.
Children using single words or less on the Autism Diagnostic Observation Schedule (
ADOS) at approximately 3 years old were drawn from the Early Diagnosis ( EDX) and Pathways in ASDlongitudinal cohorts. Age‐3 predictors of Age‐19 ADOSlanguage level were identified using Classification and Regression Trees ( CART) in the EDXsample. Linear mixed models examined the effects of CART‐identified predictors on Vineland expressive communication ( VExp) trajectories from Age‐3 to Age‐19. The same linear mixed models were examined in the Pathways sample, identifying predictors of VExp from ages 3 to 10.5 years. Results
Significantly delayed fine motor skills (T‐score < 20) was the strongest
CARTpredictor of Age‐19 language. In the linear mixed models, time, Age‐3 fine motor skills and initiation of joint attention ( IJA) predicted VExp trajectories in the EDXsample, even when controlling for Age‐3 visual receptive abilities. In the Pathways sample, time and Age‐3 fine motor skills were significant predictors of VExp trajectories; IJAand cognitive skills were not significant predictors. Conclusions
Marked deficits in fine motor skills may be a salient proxy marker for identifying language‐delayed children with
ASDwho are at risk for persistent language impairments. This finding adds to the literature demonstrating a relation between motor and language development in ASD. Investigating individual skill areas (e.g., fine motor and nonverbal problem‐solving skills), rather than broader indices of developmental level (e.g., nonverbal IQ) may provide important cues to understanding longer‐term language outcomes that can be targeted in early intervention.