Grant: DRA : Canada Graduate Research Scholarship - Doctoral Program (CGRS D)

Parkinson's disease (PD) affects over 100,000 Canadians and up to 80% of advanced patients develop freezing-of-gait (FOG). FOG causes a stuck feeling and becoming unable to walk despite intending to move. We know little on what causes FOG in the brain, so treatment intervention designs cannot address the root cause. Understanding the brain mechanisms leading to FOG allows for effective treatment development. A critical brain area in FOG is the posterior parietal cortex (PPC), an area that combines information about how our body feels and how we contract our muscles that guide how we walk. Stimulating the brain non-invasively to change its responsiveness for a short period has shown to provide small, immediate improvements in FOG. It is unclear if stimulation delivered right before exercise training would boost the effects that training alone may have. The goal of the project is to determine if stimulating the PPC before training designed to reduce FOG can make the training more effective. To investigate this, a 4-week intervention will include 120 participants with FOG sorted into an "active" or "sham" stimulation group. In the "active" group the PPC will be stimulated to increase excitability, in the "sham" group all the same steps will be taken but no real stimulation will be applied. Immediately after stimulation, both groups will do action-observation training known to be beneficial for FOG. Before and after the intervention, FOG will be compared between groups to determine if priming the PPC by increasing excitability can enhance effects of exercise training (vs. action-observation training alone). Neuroimaging will assess changes in the connections between brain regions before and after the intervention to determine the long-term effect of stimulation on the brain pathways acted on by exercise to reduce FOG. Overall, this work aims to better understand brain-based mechanisms of FOG, highlighting how the brain changes to improve treatment.