Few reliable data are available on the global prevalence of Parkinson's disease, but it is estimated that 4 million people are suffering from the disease world-wide. Parkinson's disease affects all ethnic groups. Although Parkinson's disease occurs in every part of the world, because it is mainly an illness of later life, it is more common in developed countries where people live longer. The overall prevalence of Parkinson's disease in Europe is approximately 1.6 – 1.8 per 100 in persons over 65 years of age. Because of the ageing of the world population, the importance of Parkinson's disease as a public health issue is expected to increase.

What is Parkinson's Disease?
Parkinson's disease, also known as PD or Parkinson's for short, is a chronic, progressive disorder of the central nervous system that affects various parts of the body, causing:

• Tremor (uncontrolled shaking, usually in the hands or feet and when the muscles are relaxed)

• Stiffness in the muscles

• Slowness

• Difficulty when starting movements

The disease is named after a London doctor, James Parkinson, who first recognised its main features, particularly the characteristic uncontrolled shaking of the limbs. His Essay on "The Shaking Palsy", written in 1817, provided the basis for all later research.

The cause of Parkinson's disease is unknown. What is known is that it results from a deficiency of the chemical messenger (neurotransmitter) dopamine, which is produced by the brain and plays a vital role in the control of voluntary movement.

In Parkinson's disease, dopamine-producing cells are lost from the brain, causing a shortage of dopamine. The clinical symptoms of Parkinson's disease occur when there is not enough dopamine in the brain to generate this signal for movement control.

Which parts of the body are affected, and how badly, differs among individuals. Although the symptoms tend to get worse as time goes on, this usually happens very slowly. Meanwhile, treatment for symptoms is available, and there is a lot that can be done to minimise any problems.

Management of Parkinson's Disease
Since the symptoms of Parkinson's disease are due to a shortage of dopamine in the brain, the main aim of drug therapy is to replace or augment the supply of this chemical. The use of levodopa, which is converted into dopamine in the brain, revolutionised the treatment of Parkinson's disease. The advantage of levodopa treatment is that it controls the symptoms of Parkinson's disease and most people can tolerate it.