Brain function underlying adaptive sensorimotor control in children with and without Developmental Coordination Disorder
Pangelinan, Melissa Marie
Clark, Jane E
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One child in every classroom (6% of children) suffers from Developmental Coordination Disorder (DCD). Children with DCD exhibit marked impairments in movement planning and adaptive visuomotor behavior. However, few studies have investigated the brain functions that underlie behavioral difficulties exhibited by children with DCD. The overarching objective of this dissertation was to examine brain function using electroencephalography (EEG) both at rest and during the performance of visuomotor tasks of different levels of complexity (i.e. static vs. dynamic task environments) to determine if deficits in motor behavior are related to disrupted brain function in children with DCD. The first study revealed that the cortical activation patterns exhibited by children with DCD at rest were different than their typically developing (TD) peers, particularly for the left motor cortical region. Moreover, the activation patterns of children with DCD were similar to the patterns previously reported for young TD children, suggesting a "maturational lag" in brain activation specific to motor function. For the remaining studies, children performed line drawing movements on a computer tablet towards visual targets presented on a computer screen. These studies examined whether or not children with DCD exhibit different cortical activation patterns during the execution of goal-directed drawing movements. In Study 2, children performed simple drawing movements to stationary targets. The performance of children with DCD followed the same age-related developmental trajectory as TD children. However, children with DCD engaged motor planning and control brain areas to a greater extent throughout the movement compared to TD children, suggesting greater cortical effort to complete the task. For the last two studies, children performed drawing movements in dynamic environments in which visual stimuli cued participants to either abruptly stop ongoing movements (Study 3.1) or to modify movements online to displaced target locations (Study 3.2). Results from Study 3.1 demonstrated that children with DCD do not have difficulties inhibiting movements, a finding that may be attributed to similar cortical activation patterns as the TD children in response to stop signals. Study 3.2 revealed that children with DCD exhibit difficulties modifying movements online, which may be due to a lack of preparatory cortical activation in this group. Taken together, this dissertation provides evidence that disrupted cortical function both at rest and during movement planning may underlie differences in motor performance in DCD.