Definition

Parkinson's disease (PD) is a chronic, progressive disorder of the nervous system. A chronic disorder continues for long periods of time, usually many years. Parkinson's disease affects a person's muscular coordination. Symptoms of PD include tremor (shaking), rigidity in some muscles, slow movements, and problems with maintaining normal posture. The disease is caused by the death of cells in one of the movement control centers of the brain. These nerve cells control body movement.

Description

Parkinson's disease affects about five hundred thousand people in the United States. It occurs with equal frequency in men and women. About fifty thousand new cases appear each year. The disease usually develops when a person is in his or her late fifties or early sixties. It develops gradually over a matter of months and years. A PD patient slowly loses control over the muscles that...