Brain Training to Improve Balance in Parkinson's Disease

Inclusion Criteria: People with Parkinson with mild-moderate disease and severe disability (but able to stand and walk unaided (Hoehn and Yahr stage ≤4) be eligible if: * in everyday life, they do less than the recommended aerobic exercise for older adults (i.e., vigorous exercise done \<3 times per week, 20 min per session; or moderate exercise done \<5 times per week, 30 min per session). * they have experienced at least one fall and one episode of freezing of gait in the past year. * they are taking stable dopaminergic pharmacotherapy (stable dose for at least 1 month) or are still without treatment and not expected to start treatment within the next 3 months. As long as all criteria are met - we will not impose any lower (assuming they are adults) or upper age limit for recruitment. Exclusion Criteria: * severe lower limb motor impairments and/or requirement of a walking aid or wheelchair * previously diagnosed with stroke or dementia * having metal implants in the head (i.e. deep brain stimulator or aneurysm clips) * any other known medical, mental health, or physical condition which may interfere with balance. * patients on beta-blocking agents or antipsychotics * patients with other neurological, orthopaedic, or cardiac co-morbidities that make them unfit to do exercise or interferes with balance and cognitive functions required to participate in this study * patients with psychiatric diseases diagnosed in the past year by a psychiatrist * patients with dementia * those unable to tolerate the exergame task.