Developmental coordination disorder (DCD) affects 5-6% of the school-age population, equating to ~400,000 children, or 1-2 students in every Canadian classroom. Children with DCD find it hard to learn motor skills and perform everyday activities, such as getting dressed, tying shoelaces, using utensils, printing, riding a bicycle, or playing sports. Researchers and clinicians do not know what causes DCD or why children with DCD struggle to learn motor skills. Using MRI, this study will increase understanding of how the brain differs in children with/without DCD and determine if rehabilitation can change the brain and improve outcomes of children with the disorder.

SPECIFIC OBJECTIVES AND HYPOTHESES

The proposed study proposed is designed to test the overall hypothesis that, compared to typically-developing children, children with DCD (+/- ADHD) will show differences in brain structure and function, and that rehabilitation will be associated with brain differences that reflect improvement of motor function. The investigators will address three specific objectives:

Objective 1: To characterize structural and functional brain differences in children with DCD and typically-developing children.

Hypothesis: Compared to typically-developing children, the investigators expect that children with DCD will show smaller cerebellar volume, differences in microstructural development in motor, sensory and cerebellar pathways, decreased strength of connectivity in resting, default mode, and motor networks. Children with DCD+ADHD will show poorer function in frontal and parietal areas compared to children with DCD (Langevin et al., 2014).

Approach: The investigators will use magnetic resonance (MR) imaging and advanced MR techniques to characterize brain structure and function; the investigators will use morphometry to measure cerebral and cerebellar volumes, diffusion tensor imaging (DTI) to assess microstructural development, functional connectivity MRI to measure connectivity in different brain networks, and fMRI to explore patterns of brain activation during a mental rotation task.

Objective 2: To determine if current best-practice rehabilitation intervention induces neuroplastic changes in brain structure/function and positive outcomes in children with DCD.

Hypotheses: Compared to children in the waitlist control group, the investigators expect that children in two treatment groups (DCD and DCD+ADHD) will show: (1) strengthened functional connectivity in resting, default mode, and motor networks; (2) increased integrity of the frontal-cerebellar pathway; (3) increased gray matter volume in the dorsolateral prefrontal, motor and cerebellar cortices; and (4) improved performance and satisfaction ratings of child-chosen functional motor goals. The investigators also expect that there will be a positive association between functional improvements and changes in brain structure/function.

Approach: The investigators will measure brain changes pre- and post-intervention between children with DCD and DCD+ADHD (treatment versus waitlist control). As part of treatment, children will identify three functional motor goals as a target for intervention. The investigators will use the Canadian Occupational Performance Measure (COPM; Law et al., 2005) to measure the child's rating of their performance and satisfaction pre- and post-intervention. To supplement the COPM, the occupational therapist will videotape the child performing each of their motor goals before and after intervention, and an independent occupational therapist will use the Performance Quality Rating Scale (PQRS) to objectively measure performance and change in performance (Miller et al., 2001). As a secondary measure, the investigators will evaluate fine and gross motor skills using the Bruininks-Oseretsky Test of Motor Proficiency-2 (BOT-2: Bruininks & Bruininks, 2005).

Objective 3: To determine if neuroplastic and functional changes are retained at 3-month follow-up.

Hypothesis: The investigators expect children who maintained functional gains will show increased functional connectivity in brain networks, increased integrity of the frontal-cerebellar pathway, and increased gray matter volume (as in Objective #2) compared to children who did not maintain their functional gains. If most of the children maintain their functional gains, the investigators expect improvements in brain structure and function to have remained or improved from the post-intervention scan.

Approach: MR sequences and child ratings of performance and satisfaction of their functional motor goals will be repeated in both treatment and waitlist groups.

The investigators intend to recruit 30 typically-developing children, 30 children with DCD and 30 children with DCD+ADHD.

Neuroimaging analyses will include region of interest analyses (sensory, motor, and cerebellar pathways) as well as whole brain analyses using tract-based spatial statistics.

Inclusion Criteria:

• children with suspected DCD based on history and results of motor testing (MABC-2) and parent questionnaire (DCDQ) and interview
• typically developing children who score at or above 25th percentile on MABC-2

Exclusion Criteria:

• a medical condition that could explain motor problem, such as cerebral palsy, significant intellectual disability, or visual impairment
• children with ferrous metal in their body