Brain Activity During Gait in Parkinson's

Lay Summary: Walking problems, such as slow and short steps, are very common in Parkinson's disease and lead to increased falls risk, as well as reduced mobility and quality of life. Walking issues are difficult to treat as medication interventions do not restore walking ability in people with Parkinson's, therefore physiotherapy approaches are used to help improve walking. Various physiotherapy strategies have been used, such as internal (thinking about bigger steps) or external prompts. External prompts include auditory (a metronome beat to step in time to), visual (lines to step over on the floor) and tactile (metronome-like vibration to step with) prompts that are very commonly used to improve walking in Parkinson's. However, the reason why walking improves in people with Parkinson's with these physiotherapy strategies is unknown, which has led to not all patients benefiting and only short-term walking improvements being seen. The main issues are that it is unclear if these various internal or external prompt strategies are effective with the progression of Parkinson's disease, and it is unknown which type of strategy is most effective at different disease stages or with more severe walking impairment, such as freezing (the inability to progress walking for short periods despite wanting to do so). Being able to use specific brain regions to pay attention to different internal or external prompts has been suggested to be the reason why people with Parkinson's can overcome their walking problems, but this has not been tested. Therefore, this study will use state-of-the-art digital technology to measure walking and brain activity changes with different internal and external prompts. The investigators think that the walking improvement with different prompt strategies relies on the ability to activate specific brain regions, and that brain region activity in response to internal or external prompts will change at different stages of Parkinson's disease. Ultimatel