Parkinson’s disease

A neurological disorder that causes muscle tremor, stiffness, and weakness. The characteristic signs are trembling, rigid posture, slow movements, and a shuffling, unbalanced walk. The disease is caused by degeneration of, or damage to, cells in the basal ganglia of the brain, reducing the amount of dopamine (which is needed for control of movement). It occurs mainly in elderly people and is more common in men. The disease usually begins as a slight tremor of 1 hand, arm, or leg, which is worse when the hand or limb is at rest. Later, both sides of the body are affected, causing a stiff, shuffling, walk; constant trembling of the hands, sometimes accompanied by shaking of the head; a permanent rigid stoop; and an unblinking, fixed expression. The intellect is unaffected until late in the disease. There is no cure. Drug treatment is used to minimize symptoms in later stages. Levodopa, which the body converts into dopamine, is usually the most effective drug. It may be used in combination with benserazide or carbidopa. The effects of levodopa gradually wear off. Drugs that may be used in conjunction with it, or as substitutes for it, include amantadine and bromocriptine. Surgical operations on the brain are occasionally performed. Untreated, the disease progresses over 10 to 15 years, leading to severe weakness and incapacity. About one third of sufferers eventually develop dementia.