Associations of Dyspraxia with Impaired Adaptive Behavior In Children with Autism

Background:  

Impaired performance of skilled movements, reflective of developmental dyspraxia, is a consistent finding in children with Autism Spectrum Disorders (ASD) (Mostofsky et al., 2006; Dzuik et al., 2007; Dewey et al., 2007; Dowell et al., 2009). Furthermore, dyspraxia in autism has been found to be robustly correlated with measures of the core social and communicative impairments that define the disorder (Dziuk et al., 2007; Dowell et al. 2009). Development of skilled movements is also critical in a child’s ability to function effectively and independently in their daily environment. This “adaptive” functioning has been found to be impaired in autism; children with ASD have been found to show poorer daily living skills than their typically developing peers and than children with other developmental disorders (Kenworthy et al., 2009).

Objectives:  

To examine whether impaired adaptive functioning is associated with dyspraxia in children with ASD, by examining adaptive behavior ratings and praxis performance for children with ASD and typically developing (TD) children.

Methods:  

Participants included 26 children, ages 8-12 years: 14 with ASD (2 female) and 12 TD children (4 female). Groups were matched on age, gender, IQ, race, and handedness.  Praxis was measured using the Florida Apraxia Battery, modified for children (Mostofsky et al., 2006) which examines for errors in performance of gestures to command, to imitation, and with tool use; total percent correct served as the main variable of interest. Adaptive behavior was measured using the Adaptive Behavior Assessment System, Second Edition (ABAS-II); variables of interest included subscales for Conceptual, Social and Practical adaptive behavior, as well as a Global composite score.  Independent t-tests were used to examine effect of diagnosis on praxis and ABAS-II scores. Pearson correlations were used to examine the relationship of ABAS-II composite scores with total Praxis scores.

Results:  

Independent sample t-tests revealed significant differences between ASD and TD groups for praxis performance (t= 4.824; p< .0001) and significant differences between ASD and TD groups for all composite scores on the ABAS-II (Global t= 8.885; p< .0001; Conceptual t= 5.681; p<.0001; Social t= 8.34; p<.0001 and Practical t= 8.523; p<.0001). Pearson tests revealed a significant correlation between praxis performance and global adaptive behavior (R= .709; p <.0001), as well as all three adaptive behavior sub-domains: Practical (R= .744; p <.0001), Social (R=.700; p<.0001), and Conceptual (R= .604; p = .001).  These relationships remained consistent after controlling for IQ.

Conclusions:  

Our findings reveal robust associations between development of adaptive abilities and praxis across children with ASD and TD children.  As expected, a particularly robust association between praxis and adaptive abilities in the Practical domain, which includes skills for basic self-care (e.g. grooming oneself), was found. Significant associations were also found between praxis and adaptive social functioning (e.g. engaging in recreational play) and conceptual functioning (e.g. self-directing tasks). These findings suggest that common mechanisms necessary to development of skilled behaviors may contribute to the motor, social, communicative, and self-care impairments displayed by children with ASD.