Jill Zwicker

Developmental Coordination Disorder (DCD) is neurodevelopmental disorder that affects a child's ability to learn and perform motor skills which significantly interferes with their activities of daily living. Currently only one study has identified volume-based brain differences in children with DCD compared to typically developing (TD) children. Furthermore, no study has yet determined if occupational therapy intervention induces a change in grey matter volume in this population. The objectives for this study were to: (1) compare grey matter volume in children with DCD and TD children; (2) examine the relationship of grey matter volume to motor function and attentional performance; and (3) examine neuroplastic changes in grey matter volume in children with DCD following Cognitive Orientation to Occupational Performance intervention. Objectives 1 and 2 were addressed using 30 DCD and 12 TD MRI scans for cross-sectional voxel-based morphometry with a one-way Analysis of Variance (ANOVA) design. Objective 3 was addressed using 20 MRI scans for pre-post longitudinal voxel-based morphometry with a Repeated Measures ANOVA design. Regression analyses were used to examine the relationship between grey matter volume, motor function, and attentional performance. The baseline results revealed that children with DCD had greater grey matter volume in the left superior frontal gyrus (working memory). Poorer motor function was associated with greater grey matter volume in the right middle frontal gyrus, left frontal pole, and superior frontal gyrus. Greater grey matter volume in parietal regions (left precuneus, left superior parietal lobe) was associated with poorer attentional performance. After intervention, grey matter volume decreased in right-sided regions associated with self-regulation (posterior cingulate gyrus), voluntary thinking, cognitive and motor connections (middle cingulate) and executive functioning (superior frontal gyrus). This study suggests that children with DCD may have altered brain development and that CO-OP intervention may facilitate brain maturation in targeted regions.

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Developmental coordination disorder is a common neurodevelopmental disorder that is under-recognized, under-diagnosed, and under-treated. No standard of care exists in British Columbia to assist families to access diagnostic and rehabilitative services and supports. To affect change, it is imperative to understand parent perspectives on needed resources to access diagnosis and treatment. A cross-sectional study using the impACT for DCD questionnaire explored barriers and facilitators families encounter when navigating school and healthcare systems in British Columbia. This study aimed to understand parent perspectives and priorities regarding needed resources and programs. Descriptive data analysis for close-ended questions was used to understand data trends. Inferential statistics were utilized to understand differences between variables. Content analysis was used to explore emergent themes from open-ended questions. Families identified barriers to access a timely diagnosis, which included their own limited awareness and poor understanding from healthcare professionals and educators. Long waitlists for publicly funded assessments and inconsistent access to school-funded clinical evaluations possibly led families to seek private testing. A lack of dedicated funding for treatment, coupled with inconsistent access to school-based therapy, likely contributed to obtaining private treatment for families who had the resources to pursue this option. There was a decline in active therapy with age, with younger children more likely to receive therapy. Changing priorities of social and emotional function for older children, in conjunction with increasing financial burden, likely led to this decline in therapy use. Parents reported that inconsistent access to classroom supports may have contributed to social and emotional challenges for their children. Families identified the need for funded diagnostic services, coupled with education for healthcare professionals, educators, and the community. Collaborative partnerships between physicians, therapists, and educators are integral for early detection. Children with DCD require funded, multidisciplinary treatment that addresses physical, social, and emotional function. At school, children with DCD need classroom supports, to enable successful participation in the curriculum. Regrettably, all children in this study presented with social and emotional challenges, suggesting that the current service model in British Columbia is not meeting their needs, necessitating policy changes to increase supports and services for children with DCD.

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Developmental Coordination Disorder (DCD) is a neurodevelopmental disorder that affects a child’s ability to learn motor skills and participate in self-care, educational, and leisure activities. The cause of DCD is unknown, but evidence suggests that children with DCD have atypical brain structure and function. Resting-state MRI assesses functional connectivity by identifying brain regions that have correlated activation during rest. As only a few studies have examined functional connectivity in this population, our objective was to compare whole-brain resting-state functional connectivity of children with DCD and typically-developing children, and examine the correlation of functional connectivity with behavioural measures of motor function and ADHD symptoms. Children 8-12 years old were classified as DCD if they scored ≤16th percentile on the Movement Assessment Battery for Children - 2nd edition (MABC-2) and scored in the suspected or indicative range on the DCD Questionnaire (N=35). The control group included children with a score ≥25th percentile on the MABC-2 (N=23). Children were excluded if they were born preterm (38 weeks), were diagnosed with other conditions that could affect their motor proficiency, or had high levels of motion during scans.We used Independent Component Analysis (ICA) to identify resting-state networks. We compared functional connectivity between children with DCD and typically-developing children across 19 networks, controlling for age and sex. Using Pearson’s r, we examined the correlation of functional connectivity and behavioural measurements. Children with DCD demonstrate altered functional connectivity between the sensorimotor network and the posterior cingulate cortex (PCC), and the posterior middle temporal gyrus (pMTG) (p0.0001). The functional connectivity between the sensorimotor network and the PCC (r=0.47, p0.0001) and right precuneus (r=0.46, p=0.003) was positively correlated with motor function, regardless of diagnosis.Previous evidence suggests the PCC acts as a link between functionally distinct networks. Our results indicate that ineffective communication between the sensorimotor network and the PCC might play a role in inefficient motor learning seen in DCD. The pMTG acts as hub for action-related information and processing, and its involvement could explain some of the functional difficulties seen in DCD. This first-of-its-kind study increases our understanding of the neurological differences that characterize DCD.

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Developmental coordination disorder (DCD) is a neurodevelopmental disorder of unknown etiology characterized by poor motor coordination and difficulty learning motor skills. Recent research has shown brain differences in children with DCD compared to typically-developing children. Diffusion Tensor Imaging (DTI) is a neuroimaging technique used to identify diffusion properties of white matter of the brain. Only a handful of studies have started to elucidate the white matter pathways that are implicated in children with DCD. These studies used tractography to look at a priori white matter pathways. The objective of this thesis is to be the first to apply a DTI method called tract-based spatial statistics (TBSS), a user independent analysis of the whole brain white matter to investigate the neural correlates of children with and without DCD. We hypothesized that the white matter differences would be widespread and implicate white matter pathways such as the: corticospinal motor tract (CST); sensorimotor pathways of the posterior thalamic radiation (PTR); corpus callosum; and cerebellar pathways (CP). To achieve our research goals, DTI data were collected from 61 children between 8-12 years of age (31 DCD; 30 TD) who had an MRI scan at a mean age of 10.02 years. Voxel-wise statistical analysis of diffusion metrics such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) was conducted using TBSS. A two-group comparison design matrix with age and attention as covariates was used. Data were corrected for multiple comparisons across space and statistical significance was set at p0.05. Lastly, we investigated whether there was a relationship between the diffusion metrics and motor performance using Spearman’s correlation coefficient.Our findings suggest that children with DCD show altered, widespread diffusion parameters of white matter in pathways associated with the CST, PTR and CP. Of clinical significance, FA and AD positively correlated with motor performance. Findings from this study will contribute to the scarcity of existing data on characterizing neural correlates of DCD. This research will help elucidate the pathophysiology of DCD and, also, inform intervention studies to investigate motor learning that will, ultimately, help optimize motor functioning in children with DCD.

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