Do Motor Difficulties Contribute to Peer Rejection and Social Isolation in ‘High-Functioning' Children with Autistic Spectrum Disorders?

Background:

Motor difficulties are described, by DSM-IV-TR, as possible contributors to peer rejection and social isolation among children with Asperger syndrome. No previous study has explicitly measured the independent contribution made by motor competence or clumsiness/dyspraxia to peer relationships among children with ‘high-functioning’ autism, Asperger syndrome, or other pervasive developmental disorders.

Objectives:

We aimed to examine the impact of measures of gross and fine motor skills, current clumsiness and dyspraxia, upon parent and teacher and reports of peer relationships and social rejection, in a large heterogeneous sample of ‘high functioning’ children with Asperger syndrome, autism, or PDD-NOS.

Methods:

Data from parental report were analysed for a sample of 303 children (4-16 years, mean age 9.0 yrs) from London, UK, which had been subject to comprehensive and standardized autism assessments (including ADI algorithm, ADOS). All subjects had normal-range intelligence. Diagnoses were defined according to DSM-IV-TR criteria, and comprised autism (N=106), Asperger syndrome (N=97), PDD-NOS (N=100). Measures of motor competence included developmental motor milestones, current fine and gross motor skills, and a dyspraxia/clumsiness index. Domains were derived by principal components analysis of a validated parent-report scale. Peer relations were measured by parent/teacher rated Social Difficulties Questionnaire peer relations score, and other standardized measures of peer acceptance or rejection.

Results:

Children with autism had similar gross motor skill deficits to those with Asperger and PDD-NOS. Fine motor skill deficits were significantly worse in both autistic and Asperger groups, in relation to PDD-NOS. Our measure of dyspraxia/clumsiness also indicated relatively more impairment in the autistic group than other diagnostic categories.

We tested the hypothesis that, controlling for the severity of non-motor autistic symptoms in all three domains of autistic disorder (i.e. ADI-R algorithm scores for qualitative abnormalities in social interaction, qualitative abnormalities in communication and restricted, repetitive and stereotyped patterns of behaviour), motor competence would account for a significant proportion of the variance in measures of peer acceptance. We found that impairments in gross motor skills (but not fine motor skills, or dyspraxia/clumsiness) independently predicted the degree of peer relationship difficulties, but the size of the effect was small (standardized beta, 0.14, p=0.018). There was no moderating effect of gender. The impact of the motor problems was similar in all three categories of diagnosis.

Conclusions:

Motor skill deficits, and dyspraxia/clumsiness are similar in children with ‘high-functioning’ autism and Asperger syndrome. Such difficulties are commonly assumed to contribute to peer-relationship problems, independent of the severity of autistic symptoms that contribute to phenotypic definition. Ours is the first study to test this hypothesis in a large sample, using standardized measures. We found a small but significant impact, relating significantly and exclusively to gross motor abilities.