Every Parkinson's patient experiences a combination of three motor symptoms, which typically worsen over time at a pace that varies from person to person. For most people, symptoms begin on one side of the body and later spread to the other side.

Classic symptoms of Parkinson's disease may include:

Tremor is usually the first symptom people notice, and unlike other tremors, these tremors are typically present when the patient is at rest. Emotional and physical stress tends to make the tremor worse. Sleep, complete relaxation and intentional movement or action usually reduce or stop the tremor. It is important to remember, however, that as many as 30 percent or more of people with Parkinson's disease do not experience tremors.

The muscles of the legs, face, neck or other parts of the body may become unusually stiff or rigid. Another common early sign of the disease is a reduced swing of the arm on one side when the person is walking.

In addition to the four classic motor symptoms, Parkinson's disease can cause a variety of other disabilities as the disease progresses:

Finally, people with Parkinson's disease may experience one or more symptoms that typically do not affect their movements. The most typical nonmotor symptoms of Parkinson's disease include:

A person with Parkinson's disease may slowly become more dependent, fearful, indecisive and passive. The person may talk less often, withdraw from people and be inactive unless encouraged to move about. Depression is very common with this disease and can be caused by chemical changes in the brain. Symptoms of depression often improve with proper treatment.

The causes for most forms of Parkinson's disease are unknown. Some evidence indicates that inherited (genetic) factors may predispose some people to develop Parkinson's disease; however, the majority of people with Parkinson's don't have a known gene abnormality. Research has indicated that there may be a connection between Parkinson's and environmental toxins that damage dopamine-producing nerves.

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Parkinson's Disease - Cedars-Sinai