What is Parkinson's disease?

Parkinson's Disease: An Overview
What is Parkinson's disease?
Parkinson's disease is a movement disorder that is chronic and progressive, meaning that symptoms continue and worsen over time. As many as one million Americans suffer from Parkinson's disease. While approximately 15 percent of people with Parkinson's are diagnosed before the age of 50, incidence increases with age. The cause is unknown, and although there is presently no cure, there are many treatment options such as medication and surgery to manage the symptoms. (For more statistics on Parkinson's disease, read our fact sheet, General Facts on Parkinson's Disease).
Parkinson's disease occurs when a group of cells in an area of the brain called the substantia nigra begin to malfunction and die. These cells in the substantia nigra produce a chemical called dopamine. Dopamine is a neurotransmitter, or chemical messenger, that sends information to the parts of the brain that control movement and coordination. When a person has Parkinson's disease, their dopamine-producing cells begin to die and the amount of dopamine produced in the brain decreases. Messages from the brain telling the body how and when to move are therefore delivered more slowly, leaving a person incapable of initiating and controlling movements in a normal way.
Parkinson's disease can also cause several different symptoms. The specific group of symptoms that an individual experiences varies from person to person. Some of the most common symptoms of Parkinson's disease are:
tremor of the hands, arms, legs, jaw and face
rigidity or stiffness of the limbs and trunk
bradykinesia or slowness of movement
postural instability or impaired balance and coordination
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