This illness has existed for thousands of years. Learn more about Parkinson disease by taking this quiz.
About 7 in 10 people with Parkinson first have a slight tremor in a hand or foot, according to the Parkinson Foundation. The tremor usually occurs when the muscles are at rest and relaxed. It usually appears on one side of the body. Later it may spread to the other side of the body, but to a lesser degree. Common symptoms as the disease gets worse include:
Secondary symptoms include: