The Relationship Between Developmental Coordination Disorder and Concurrent Deficits in Social Communication and Repetitive Behaviors Among Children with Autism Spectrum Disorder.

Children with Autism Spectrum Disorder (ASD), characterized by core deficits in social communication and restrictive behaviors, can exhibit concurrent motor incoordination and/or intellectual disability (ID). While pervasive delays in motor behavior are common, formal diagnosis of Development Coordination Disorder (DCD) is uncommon. It is not clear how DCD and ID impact core deficits in ASD. This study utilized the Simons Foundation SPARK cohort to describe the scope of motor incoordination among children with ASD and examine the interrelationships between DCD risk, ID, and ASD core deficits. 10,234 children with ASD, between the ages of 5 and 15 years, were included in the analysis. Parents completed online versions of the DCD Questionnaire (DCD-Q), Social Communication Questionnaire (SCQ) and Restrictive Behavior Scale (RBS-R). 85% of children with ASD had DCD-Q scores consistent with being at-risk for DCD, but only 14% reported a formal diagnosis. Children with ID exhibited significantly greater motor incoordination compared to children without ID (P < 0.001). Significantly, greater core deficits were identified in both children at-risk for DCD (P < 0.001) and with ID (P < 0.001). However, the effects of DCD risk were independent of ID and exhibited a medium effect size for SCQ (η = 0.063) and a small effect size for RBS-R (η = 0.04) scores. Collectively, study outcomes reinforce the pervasiveness of motor incoordination among children with ASD, both with and without concurrent ID, and provide further justification for the inclusion of motor behavior in the early intervention and prescription for children with ASD. LAY SUMMARY: This secondary data analysis of the Simons Foundation SPARK cohort found high rates (85%) of DCD risk among children with ASD. Deficits in motor coordination were greater among children with ASD with concurrent ID diagnoses. Meaningful differences in ASD core deficits (social communication and repetitive behaviors) were independently found in children at risk for DCD, both with and without ID. Autism Res 2021, 14: 804-816. © 2021 International Society for Autism Research and Wiley Periodicals LLC.