Association of difficulties in motor skills with longitudinal changes in social skills in children with autism spectrum disorder: findings from the ELENA French Cohort.

Developmental coordination disorder is a frequently co-occurring condition with autism spectrum disorder (ASD). Several cross-sectional studies have reported that children with difficulties in motor skills have a higher severity of ASD symptoms. This study aims to examine the association of difficulties in motor skills with longitudinal changes in social skills in children with ASD. Participants were drawn from the ELENA cohort, a French longitudinal cohort of children with ASD. Motor skills were assessed using the Movement Assessment Battery for Children at baseline, while social skills were measured using the Autism Diagnostic Observation Schedule (ADOS-2) and the Vineland Adaptive Behavior Scales (VABS-II) at both the baseline and a follow-up assessment conducted 3 years later. A composite score of social skills was created at baseline and at both time points. Linear regression models were performed to assess the association between difficulties in motor skills and changes in social skills, considering potential confounders such as IQ, age, and gender. The sample included 162 children with ASD. Children with difficulties in global motor skills (N = 114) showed less favorable trajectories in social skills compared to those without motor difficulties. The results were consistent when examining the ADOS-2 and the VABS-II separately. This study provides evidence for the negative impact of difficulties in motor skills on the longitudinal development of social skills in children with ASD. Interventions targeting motor difficulties may have broader benefits, extending beyond motor function to improve socialization.