Cognitive and Behavioural Comorbidity of Social and Motor Difficulties in Primary School Age Children

Background: There is substantial comorbidity between different developmental disorders.  For example, 50-80% of children with autism spectrum condition also have motor control difficulties (Green et al., 2009), and children with developmental coordination disorder may also struggle with social skills.   Research on cognitive processes in developmental disorders has typically examined one disorder at a time without regard to comorbidity.  Thus, the cognitive difficulties causing particular patterns of comorbidity remain largely unknown.

Objectives: This project aims to define the relationship between motor and social difficulties in children and the cognitive processes underlying these behaviours, in order to understand co-morbidity in developmental disorders. We have selected three cognitive systems to investigate: 1) theory of mind systems, 2) mirroring systems and 3) systems of motor control. The present study aims to examine the relationship between these three cognitive systems and social and motor behaviour, across a large population of children with and without developmental disorders.

Methods: Social and motor behaviour were assessed by parent questionnaire (Social Responsiveness Scale (SRS); Developmental Coordination Disorder Questionnaire (DCDQ); and Conners 3 ADHD Index) in a sample of 142 children aged between 5 and 11 years old.  A subset (n=68 so far) of these children completed detailed cognitive testing (Raven’s matrices, theory of mind tests, action comprehension tests and motor control tests).   Regression analyses were used to determine how well social behaviour (SRS scores) could be predicted based on the different cognitive test scores.

Results: A linear regression on the parent questionnaire data (n=142) found that scores on the DCDQ (t(139)=-5.44, p=.000) and the Conners 3 ADHD Index (t(139)=5.61, p=.000) significantly predicted scores on the SRS while age was not a significant predictor (t(139)=1.66, p=.099 ).  A preliminary linear regression on the results from the cognitive test battery (n=68) revealed that SRS scores were significantly predicted by performance on motor planning, motor sequencing and posture knowledge tasks, but not by theory of mind scores or non-verbal IQ.

Conclusions: The present study confirms previous reports of substantial overlap between parental reports of motor, social and attentional behaviours.  More critically, we show that performance on lab-based motor tasks predicts a child’s SRS score.  Further analyses of this rich dataset will reveal the ways in which certain cognitive systems relate to the behavioural profiles that form the basis for diagnosis of developmental disorders such as ASC and DCD.