HealthyCanada.com

Overview

Parkinson's disease is a chronic progressive brain disorder that results from degeneration of nerve cells in a region of the brain that controls movement. The disorder appears to be slightly more common in men than women. The average age of onset is about 60. Parkinson's disease is found all over the world. In Canada there are approximately 100000 people with Parkinson's although that number is expected to grow as the population ages.

Causes

Cells or neurons in a part of the brain produce dopamine a chemical neurotransmitter or messenger which allows for the smooth coordinated function of the body's muscles and movement. For some reason these cells begin to degenerate and are unable to produce sufficient amounts of dopamine. A shortage of dopamine causes nerve cells in the brain to fire haphazardly leaving a person unable to control their movements in the normal way.

Although there are many theories about the cause of Parkinson's disease none has ever been proved. Researchers have reported families with apparently inherited Parkinson's for more than a century. However until recently the prevailing theory held that one or more environmental factors caused the disease. The strong familial inheritance of the chromosome 4 gene is the first evidence that a gene alteration alone may lead to Parkinson's disease in some people.

Symptoms

Often the first symptom of Parkinson's disease is tremor (trembling or shaking) of a limb especially when the body is at rest. The tremor often begins on one side of the body frequently in one hand. Other common symptoms include:

• slow movement (bradykinesia)
• an inability to move (akinesia)
• rigid limbs
• a shuffling gait
• stooped posture.

People with Parkinson's disease often have reduced facial expressions and speak in a soft voice. Occasionally the disease also causes depression personality changes dementia sleep disturbances speech impairments or sexual difficulties. The severity of Parkinson's symptoms tends to worsen over time.

Treatment

Parkinson's disease is usually diagnosed by a neurologist who can evaluate symptoms and their severity. There is no test that can clearly identify the disease. Sometimes people with suspected Parkinson's disease are given anti-Parkinson's drugs to see if they respond. Other tests such as brain scans can help doctors decide if a patient has true Parkinson's disease or some other disorder that resembles it.

There is no cure for Parkinson's disease. Many patients are only mildly affected and need no treatment for several years after the initial diagnosis. When symptoms grow severe doctors usually prescribe levodopa (L-dopa) which helps replace the brain's dopamine. Sometimes doctors prescribe other drugs that affect dopamine levels in the brain.

In patients who are very severely affected a kind of brain surgery known as pallidotomy has reportedly been effective in reducing symptoms. Another kind of brain surgery in which healthy dopamine-producing tissue is transplanted into the brain is also being tested. Researchers are also trying to identify substances that will prevent dopamine-producing brain cells from dying.