Parkinson's Disease Health Center

An Overview of Parkinson's Disease

Parkinson's disease is a chronic progressive neurological disease that affects a small area of nerve cells (neurons) in an area of the brain known as the substantia nigra. These cells normally produce dopamine, a chemical (neurotransmitter) that transmits signals between areas in the brain that, when working normally, coordinate smooth and balanced muscle movement. Parkinson's disease causes these nerve cells to die, and as a result, body movements are affected.

"Parkinsonism" is a term that is often used interchangeably with Parkinson's disease. Medically, parkinsonism refers to any condition that causes symptoms similar to Parkinson's disease tremors at rest, muscle rigidity, slow movement, and changes in walking. Parkinson's disease is probably the most common form of parkinsonism. Other conditions that cause it include:

• Medications such as reserpine, Thorazine
• Toxic exposures to carbon monoxide, cyanide
• Hypothyroidism
• Hypoparathyroidism
• A variety of other neurologic conditions affecting the nerves in the substantia nigra such as Wilson's disease (a condition causing abnormal deposition of copper in the brain) and progressive supranuclear palsy

Learn more about other causes of Parkinson's.

What Are the Symptoms of Parkinson's Disease?

Common symptoms of Parkinson's disease include:

• Muscle rigidity
• Tremors
• Bradykinesia (the slowing down of movement and the gradual loss of spontaneous activity)
• Changes in walking pattern and posture
• Changes in speech and handwriting
• Loss of balance and increased falls

Who Gets Parkinsons Disease?

Approximately one million Americans have Parkinson's disease, including three out of every 100 people over the age of 60. Over 50,000 Americans are diagnosed with Parkinson's disease each year. There is increasing evidence that Parkinson's disease may be inherited (genetically passed on between family members). Men are slightly more likely to develop the disease than women.

The average age at which it is diagnosed is 60. However, about 10%-20% of those diagnosed with Parkinson's disease are under age 50, and about half of those are diagnosed before age 40. When the diagnosis is made early, it is referred to as "young-onset" Parkinson's disease.