Parkinson's disease

Parkinson's is a slowly progressive disorder of the nervous system, which affects movements like walking, talking and writing. It is named after the London doctor Dr James Parkinson (1755-1824) who first identified the disease. In the UK around 120,000 people (or 1 in 500) have Parkinson's, although the number of Parkinson's patients over the age of 60 is higher.

Parkinson's disease is caused by a loss of cells producing dopamine, a chemical which carries messages between nerve cells and muscles. The reason for the loss of dopamine producing cells is not well understood - current research is looking at genetics, environmental factors and viruses.

The condition usually develops after the age of 50 years and the important clinical features which usually start on one side of the body are:

• Tremors in hands, arms and feet;
• Rigidity of muscle (experienced as stiffness);
• Slowness of movements (called bradykinesia);

Other features are, postural problems, swallowing difficulty, communication problems and in some people depression and at a later stage dementia and falls. Clinical features vary depending on the severity.