Tremor is an unintentional, somewhat rhythmic, muscle movement involving to-and-fro movements of one or more parts of the body. Most tremors occur in the hands, although they can also affect the arms, head, face, vocal cords, trunk, and legs. Sometimes tremor is a symptom of another neurological disorder, but the most common form occurs in otherwise healthy people. Some forms of tremor are inherited and run in families, while others have no known cause. Excessive alcohol consumption or alcohol withdrawal can kill certain nerve cells, resulting in tremor, especially in the hand. Other causes include an overactive thyroid and the use of certain drugs. Tremor may occur at any age but is most common in middle-aged and older persons.

There is no cure for most tremors. The appropriate treatment depends on accurate diagnosis of the cause. Drug treatment for parkinsonian tremor involves levodopa or dopamine-like drugs such as pergolide mesylate, bromocriptine mesylate, and ropinirole. Essential tremor may be treated with propranolol or other beta blockers (such as nadolol) and primidone, an anticonvulsant drug. Dystonic tremor may respond to clonazepam, anticholinergic drugs, and intramuscular injections of botulinum toxin. Eliminating tremor "triggers" such as caffeine and other stimulants from the diet is often recommended. Physical therapy may help to reduce tremor and improve coordination and muscle control for some patients. Surgical intervention, such as thalamotomy and deep brain stimulation, are usually performed only when the tremor is severe and does not respond to drugs.

Although tremor is not life-threatening, it can be embarrassing to some people and make it harder to perform daily tasks.

Prepared by the National Institutes of Health