Parkinson's disease is a movement disorder of the nervous system that worsens over time. The nervous system is a network of nerve cells that controls many parts of the body, including movement.
Symptoms start slowly. The first symptom may be a barely noticeable tremor in just one hand or sometimes a foot or the jaw. Tremor is common in Parkinson's disease. But the disorder also may cause stiffness, slowing of movement and trouble with balance that raises the risk of falls.
In the early stages of Parkinson's disease, your face may show little or no expression. Your arms may not swing when you walk. Your speech may become soft or slurred. Symptoms get worse over time.
Although Parkinson's disease can't be cured, medicines may help symptoms get better. Sometimes a healthcare professional may suggest surgery to help control parts of the brain. This surgery may help lessen symptoms.