Motors Skills in High Functioning Autism

Background:  High Functioning Autism (HFA) is part of Autism Spectrum Disorder (ASD). It is characterized by impairment in social interaction and repetitive behaviour but without intellectual disability. Clinically, by six months of age they present with motor impairments and then 50% of them present Developmental Coordination Disorder (DCD), with major impacts on social and working life. By contrast, there are few studies on motor skills in ASD, and their results are heterogeneous. 

Objectives:  The objectives of this study are: (1) to describe motor skills in HFA, using objective movement analyzing tools, on different motor levels from the reflex and automatic level (« low level »), to the voluntary level (« high level »); (2) to evaluate the cognitive demand of motricity. Our hypotheses are: (1) Subjects with HFA present with impairment in low and high level movements. (2) They have an impairment in dual task (motor and cognitive task) compared to typically developing subjects. 

Methods:  Motor functioning has been first evaluated clinically with a validated standardized scale of motor development (DCDQ) and a medical interview based on DCD’s DSM 5 criteria. We evaluated motor skills in a movement laboratory (using posturography, kinematic analysis and pointing monitoring) during four motor tasks (standing, walking, pointing and intercepting task) and during three dual tasks (walking with alphabet, talk and counting). We included twenty-eight participants aged of 12 to 30 years old: 14 subjects with HFA and 14 typically developed subjects. 

Results:  Clinically, half of the participants with HFA presented with impairment in motor functioning, and with alteration of childhood motor development. These results are consistent with DCD prevalence in ASD (50%). Experimentally, we found a tendency in impairment of low level motor ability (standing and walking eyes opened) and a significant alteration in the high level motor skills (pointing and interception) associated with an impairment in complex motor integration (dual task and standing with eyes closed). 

Conclusions:  In this study, we showed that HFA individuals are capable of performing a range of motor skills, but that they are perhaps using modified processes: overweighted vision, slower motor planning while accuracy is intact, high cognitive requirement of motricity, more variable movements. Furthermore, HFA individuals present major impairments in different areas of functioning. Automatized tools seem to be interesting to develop early screening tools and potential biomarker.