Integrating Brain Imaging and Rehabilitation to Improve Outcomes for Children With Co-occurring DCD & ASD

About 5% of children have DCD, a neurodevelopmental disorder that significantly affects their ability to learn motor skills, such as tying shoelaces, learning to print, or riding a bicycle (APA 2013). DCD interferes with school performance, vocational activities, leisure pursuits; it has a lifelong impact, and 75% of children with DCD will continue to experience motor difficulties as adults (Kirby 2014). DCD is highly comorbid with other neurodevelopmental disorders including Autism Spectrum Disorder (ASD) (Green 2009) and Attention Deficit Hyperactivity Disorder (ADHD) (Piek 1999) which exacerbates children's motor and functional problems (Kirby 2014).

Until recently, motor deficits in children with ASD have largely been ignored. Since the Diagnostic and Statistical Manual for Mental Disorders-5th ed. (DSM-5) was published in 2013, a dual diagnosis of ASD and DCD is now permitted. Over 50% of children with ASD have been reported to have DCD (Green 2009), with the degree of motor impairment correlating with autism severity (Dzuik 2007).

The overlap of DCD and ASD is not well-studied, but the high co-occurrence prompts one to wonder whether there are common and distinct neural markers that define these neurodevelopmental disorders. Neuroimaging studies have begun to unravel their neural underpinnings. Abnormalities in the cerebellum (D'Mello 2016; Foster 2015; Liu 2017; Zwicker 2009, 2011) and corpus callosum (Langevin 2014; Frazier 2009) are common to both disorders, but few studies have compared children with DCD and those with co-occurring ASD. Preliminary evidence indicates alterations in network patterns that are unique to the DCD+ASD group when compared to either single diagnosis of DCD or ASD (Caeyenberghs 2016). As one of the first neuroimaging studies to touch upon a dual diagnosis of DCD+ASD, Caeyenberghs et al. found that paralimbic regions exhibit altered connectivity in singular disorders, which are disorder specific to ASD or DCD; however, children meeting criteria for both DCD and ASD exhibit more widespread over-connectivity, specifically in the left association area and medio-occipitotemporal gyrus when compared to DCD alone. While in its infancy, neuroimaging studies suggest that DCD and ASD may have common but also distinct neural underpinnings (Caeyenberghs 2016; Caçola 2017); further research is needed to better understand the neural correlates of each disorder and its co-occurrence.

Current best-practice to improve motor function in children with DCD is Cognitive Orientation to Occupational Performance (CO-OP) (Smits-Engelsman 2013). CO-OP is a task-specific approach designed to improve motor-based skills that a child needs or wants to master; it is a cognitive-based, problem-solving approach that uses verbal mediation and identifies strategies to support skill acquisition (Polatajko 2001). It is largely unknown if children with co-occurring DCD and ASD benefit from CO-OP. Although motor impairment and functional problems are common in ASD, they are rarely the focus of therapy. The primary focus of therapy for children with ASD has always been on social and communication skills or managing sensory processing differences. Preliminary findings from a case study with two children diagnosed with ASD suggest that CO-OP is feasible and able to induce clinically significant improvements in self- and parent-rated performance on each of their motor goals (Rodger 2009). However, a larger sample is needed to confirm these findings.

The CO-OP approach has been effective in meeting child-chosen functional motor goals (Polatajko 2001; Miller 2001), but the neural basis for these improvements is still not known. The investigators are currently investigating brain changes in structure and function associated with CO-OP intervention for children with DCD+/-ADHD and would like to expand their study to include children with co-occurring ASD and DCD. This novel study will help to unravel the brain differences between these co-occurring conditions and explain if and why rehabilitation may benefit children with the dual diagnosis of DCD and ASD.