Parkinson's Disease Overview
by Dr. Patrick Sweeney

Parkinson's disease is a chronic progressive neurological disease that affects nerve cells (neurons) in an area of the brain near the neck, known as the substantia nigra.

These cells normally produce dopamine, a chemical (neurotransmitter) that transmits signals between areas in the brain. These signals, when working normally, coordinate smooth and balanced muscle movement.

Parkinson's disease, however, causes neurons in the substantia nigra cells to die, leading to a lack of dopamine in the brain, especially in the part of the brain known as the basal ganglia.

The basal ganglia are responsible for organizing movement commands from other parts of the brain. The loss of dopamine causes patients to lose the ability to control their body movements.

Approximately one million Americans have Parkinson's disease. More than 50,000 Americans are diagnosed with Parkinson's disease each year.

There is increasing evidence that Parkinson's disease may be inherited. Men after the age of 60 are more likely to develop the disease than women.

The average age at the onset of symptoms is 60. However, 10 percent of patients are diagnosed before age 40.

The major symptoms of Parkinson's disease include:

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