What is the nature of motor impairments in autism, are they diagnostically useful, and what are the implications for intervention?

There is general agreement that alongside the core diagnostic features of autism spectrum disorder (ASD), motor abnormalities and delays in motor development are common features despite the likely presence of multiple etiologies and subtypes of ASD. Whether and to what extent these motor impairments show an ASD-specific profile that can be differentiated from general vulnerability associated with atypical neurodevelopment remains equivocal and a hot topic of debate. This review will critically evaluate the growing body of evidence on motor impairments from prospective studies of infants at high familial risk for ASD, studies of family members with intermediate phenotypes, cross-syndrome and comorbidity studies, and motor-based interventions in ASD. It is argued that a more nuanced view of the pervasiveness of ASD-specific motor abnormalities is needed, and there are a number of significant methodological issues, including comorbidity, small sample sizes, lack of meaningful subtyping, exclusion of cognitively impaired individuals, and lack of longitudinal cross-syndrome designs. To overcome these methodological challenges will require a concerted effort across multiple sites with advances in analytical approaches in neuroimaging and analysis of micro-movements holding a great deal of promise for early diagnosis, development of unified models of pathophysiology, and personalized treatments that are inclusive of the wider spectrum of cognitive abilities in ASD.