Shedding light on the brain—characterizing functional brain activation during simple and complex walking after stroke

Independent ambulation in the community is often stated as important amongst people post-stroke. Walking within the community can be complex, requiring speed changes during walking, attention or interaction with the environment and other people. After a stroke, the ability to complete these specific walking tasks is often impaired. Currently, determining appropriate gait rehabilitation interventions post-stroke is based on clinical observations such as motor, sensory, cognitive, and balance ability. These methods, however, may not be sensitive or objective enough to detect change or appropriateness for specific interventions. Assessment of individual functional brain activation is a promising method for determining appropriateness of gait rehabilitation interventions and can provide insight on resource allocation, neural efficiency, and neural compensations. This dissertation consists of four independent studies. The first is a review of the current findings of brain activation during walking post-stroke and identified the gaps within the literature. This review then informed the next three studies where functional near-infrared spectroscopy was used to assess real-time brain activation during different types of walking: normal-paced, slow, fast, and dual-task walking. Results from these studies show task- specific activation of brain regions across the frontal and parietal cortices as well as relationships between brain activation and clinical measures of impairment and performance. Notably, consistent increases in ipsilesional prefrontal cortex was observed with each walking task, premotor cortex was involved when walking was not at a normal-pace, and activation in sensorimotor and posterior parietal cortices related to gait speed. Results from these studies contribute basic scientific knowledge towards the neural correlates of walking after a stroke and can be an important reference for future interventions aimed to improve walking recovery.Medicine, Faculty ofGraduat