Parkinson's disease is the second most common chronic progressive neurodegenerative disorder. Like Alzheimer disease, the most common neurodegenerative condition in America, symptoms of Parkinson's patient's progress and worsen over time. Parkinson's disease is a disorder of the brain caused by a lack of dopamine that may result in shaking and difficulty with walking, movement, speaking, swallowing and coordination. Older adults with chronic conditions and complex illness may have an increased vulnerability to the disease. Parkinson's disease is one of the most common nervous system disorders for seniors over the age 50.