Parkinson’s disease is a progressive neurodegenerative brain disorder, which causes tremors and difficulty with movement and coordination. Parkinson’s affects nerve cells—called neurons—in a particular part of the brain called the substantia nigra. These neurons normally produce dopa- mine, a brain chemical that relays messages between the substantia nigra and other parts of the brain that control muscle movement. These dopamine-producing neurons are slowly destroyed over time, eventually preventing normal control of movement. The cause of the neuronal degeneration is unknown. In the U.S. more than fifty thousand new PD cases are diagnosed each year.
Symptoms of Parkinson’s disease (which can include, but are not limited to muscle rigidity, tremors, slowed movement, drooling, and difficulty with balance) may initially be mild and may affect one or both sides of the body.