Parkinson's disease is a degenerative disease of the brain. It affects parts of the brain that are associated with normal movement and balance.
This disease is caused by the loss of brain cells that produce dopamine. The area affected is called the substantia nigra. Dopamine is a neurotransmitter or a chemical messenger that carries signals between the neurons in the brain. Dopamine enables smooth, coordinated movements.
The symptoms appear only when around 80 per cent of the dopamine producing cells in the brain are destroyed. The earliest symptom is a fine tremor of hands while at rest.
Exactly what causes Parkinsonâ€™s disease is unclear. Most experts think that a combination of genetic and environmental factors is responsible.
The classic symptoms of this condition are a tremor or shaking of the hand or other limbs while at rest. Another classic symptom is rigidity and increased tone in the body's muscles. The movements of the body are slowed (this is termed bradykinesia) and the patient often finds difficulty in maintaining balance.
The problems are usually at the beginning of a new activity like getting up and walking. Once they begin the patients usually moves too fast, ending up almost running or out of control.