National Institutes of Health, Bethesda, Maryland 20892
April 1996
DESCRIPTION: Tremor is a rhythmic, involuntary muscular contraction characterized by oscillations (to-and-fro movements) of a part of the body. The most common of all involuntary movements, tremor can affect various body parts such as the hands, head, facial structures, vocal cords, trunk, and legs; most tremors, however, occur in the hands. Tremor often accompanies neurological disorders associated with aging. Although the disorder is not life-threatening, it can be responsible for functional disability and social embarrassment.
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CLASSIFICATIONS: There are many types of tremor and several ways in which tremor is classified. The most common classification is by behavioral context or position. There are five categories of tremor within this classification: resting, postural, kinetic, task-specific, and hysterical. Resting or static tremor occurs when the muscle is at rest, for example when the hands are lying on the lap. This type of tremor is often seen in patients with Parkinson's disease. Postural tremor occurs when a patient attempts to maintain posture, such as holding the hands outstretched. Postural tremors include physiological tremor, essential tremor, tremor with basal ganglia disease (also seen in patients with Parkinson's disease), cerebellar postural tremor, tremor with peripheral neuropathy, post-traumatic tremor, and alcoholic tremor. Kinetic or intention (action) tremor occurs during purposeful movement, for example during finger-to-nose testing. Task-specific tremor appears when performing goal-oriented tasks such as handwriting, speaking, or standing. This group consists of primary writing tremor, vocal tremor, and orthostatic tremor. Hysterical tremor (also called psychogenic tremor) occurs in both older and younger patients. The key feature of this tremor is that it dramatically lessens or disappears when the patient is distracted.
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TREATMENT: There are some treatment options available for tremor; the appropriate treatment depends on accurate diagnosis of the cause. Some tremors respond to treatment of the underlying condition, for example in some cases of hysterical tremor treating the patient's underlying mental problem may cause the tremor to disappear. Also, patients with tremor due to Parkinson's disease may be treated with Levodopa drug therapy. Symptomatic drug therapy is available for several other tremors as well. For those cases of tremor in which there is no effective drug treatment, physical measures such as teaching the patient to brace the affected limb during the tremor are sometimes useful. Surgical intervention such as thalamotomy may be useful in certain cases.
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RESEARCH: NINDS investigators are currently conducting physiological studies of patients with tremors. These studies include classifying the tremor and providing appropriate therapy. The National Institute on Deafness and Other Communication Disorders also conducts research relevant to tremor.
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These articles, available from a medical library, may provide more in-depth information on tremor:
Gillepsie, M. "Tremor." Journal of Neuroscience Nursing, 23:3; 170-174 (June 1991).
Hallett, M. "Classification and Treatment of Tremor." The Journal of the American Medical Association, 266:8; 1115-1117 (August 28, 1991).
Koller, W, and Huber, S. "Tremor Disorder of Aging: Diagnosis and Management." Geriatrics, 44:5; 33-41 (May 1989).
Vinken, P, Bruyn, G, and Klawans, H. (eds). Chapter 35 in Handbook of Clinical Neurology, Vol. 5(49) Elsevier Science Publishing Co, Inc., Amsterdam, pp. 583- 595 (1987).
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Information may also be available from the following organization:
International Tremor Foundation
360 West Washington Boulevard
Chicago, IL 60607
(312) 733-1893
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Last Updated: May 13, 1997.
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892