General Gross and Fine Motor Impairment Vs Specific Deficits in Prospective Control in Three-Year-Olds with Autism Spectrum Disorder

Background: Motor impairments are very common in children with Autism Spectrum Disorder (ASD). Whether some aspects of motor control should be seen as core features of the disorder is currently debated  Research point to the possibility that atypicalities in prospective control,  – i. e. to anticipate future events and adjust ones actions to these events before they occur – are particularly difficult for many people with ASD.

Objectives: The aim of the study was to compare prospective control as well as general gross and fine motor ability in 3-year-olds with and without ASD. We expected that group differences would be particularly pronounced in the prospective control task.

Methods: The general motor tasks consisted of the gross and fine motor subscales of the Mullen Scales of Early Learning (MSEL). The prospective control task was to draw a line from one point to another within an outlined curve-shaped path on paper (named the Way Home Task). In order to succeed on this task, the child has to anticipate the upcoming curves and proactively adjust his/her actions to avoid crossing the lines defining the path boundaries. The number of crosses was used as our measure of (failure) of prospective control. Twenty-eight children, 9 boys and 19 girls between 36-48 months (M= 39,9 months) from a longitudinal study of ‘high risk’ infant siblings participated (all children were at high risk for ASD due to having an older sibling with the disorder). Diagnosis according to DSM 5 was decided upon in a professional team according to best practice, based on clinical assessment in a clinical research setting with the Mullen Scales of early learning, ADOS-2, ADI-R, Vineland and clinical observations. Twelve children were diagnosed with ASD and 16 got no diagnosis.

Results: Independent sample t-test showed that there was a significant difference between the groups on the two MSEL motor scales as well as the specific prospective control task (all Ps < .05, one tailed). Grip type and visual reception subscale on the MSEL did not differ between the groups. However, logistic regression showed that gross motor ability was the only unique statistically significant predictor of diagnostic group, recording an odds ratio of 1.80. 

Conclusions: In line with our hypothesis, the groups differed in their performance on the prospective control task. However, the groups also differed on more general fine motor as well as gross motor scales, and only the latter explained a unique portion of the variance in diagnostic status. This study indicates substantial differences in motor development in young children with ASD relative to other at risk children who did not fulfil criteria for diagnosis. With more participants reaching 3 years in our ongoing study, we will be able to more reliably assess the role of specific motor abilities, such as prospective motor control in ASD.