After Alzheimer's, Parkinson's disease (PD) is the leading neurodegenerative disorder, affecting close to a million Americans, with 50,000 new cases diagnosed every year. A progressive disorder of the nervous system affecting movement, PD typically strikes adults in mid-life. In many cases, the spread of the disease to other brain areas leads to Parkinson's disease dementia, characterized by deterioration of memory, reason, attention and planning.

