Parkinson's disease (PD) is a neurological disorder affecting approximately 1 million people in the United States. The most common symptoms of PD are tremor, slowness of movement, and/or gait and balance problems. The hallmark of PD is a loss of dopamine, a neurochemical in the brain. The dopamine producing cells, particularly in a region of the brainstem called substantia nigra, progressively die off for reasons that remain unknown. This progressive loss of cells leads to increasing disability over time.
There are also several disorders related to Parkinson's Disease that are frequently referred to as "Parkinson's Plus" syndromes or Atypical Parkinsonism. In addition to causing motor symptoms similar to Parkinson's disease, atypical disorders also severely disrupt other functions, such as cognition, vision, and blood pressure regulation. These atypical syndromes include Lewy Body Dementia (LBD), Multiple System Atrophy (MSA), Corticobasal Degeneration (CBD) and Progressive Supranuclear Palsy (PSP).