An involuntary, rhythmic, oscillating movement in the muscles of part of the body, most commonly those of the hands, feet, jaw, tongue, or head. Tremor is the result of rapidly alternating muscle contraction and relaxation. Occasional tremors are experienced by most people and are due to increased production of the hormone adrenaline (epinephrine). A slight, persistent tremor is common in elderly people.
Essential tremor, which runs in families, is a slight-to-moderate tremor that may be temporarily relieved by consuming a small amount of alcohol or by taking beta-blocker drugs.
Coarse tremor (4–5 muscle movements per second), which is present at rest but reduced during movement, is often a sign of Parkinson’s disease.
An intention tremor (tremor that is worse on movement of the affected part) may be a sign of cerebellar ataxia.
Tremor may also be caused by multiple sclerosis, Wilson’s disease, mercury poisoning, thyrotoxicosis, or hepatic encephalopathy; drugs, such as amfetamines and caffeine; and withdrawal from drugs, including alcohol.
A ?ne involuntary movement. Tremors may be seen in projecting parts like the hands, head and tongue, or they may involve muscles. Coarse tremors, which prevent a person from drinking a glass of water without spilling it, are found in MULTIPLE SCLEROSIS (MS) and in CHOREA; somewhat ?ner tremors, which produce trembling of the hands or tongue when they are stretched out, are caused by alcoholism (see ALCOHOL) and other forms of poisoning, by PARKINSONISM, and by the weakness which follows some acute disease or characterises old age. A ?ne tremor of the outstretched ?ngers is a characteristic of thyrotoxicosis (see under THYROID GLAND, DISEASES OF); very ?ne tremors, visible in the muscles of face or limbs and known as ?brillary tremors, are present in general paralysis of the insane (see SYPHILIS), and in progressive muscular atrophy or wasting palsy. Tremors may occur at rest and disappear on movement as in Parkinsonism, or they may occur only on movement (intention tremors) as in cerebellar disease.
n. a rhythmical and alternating movement that may affect any part of the body. The physiological tremor is a feature of the normal mechanism for maintaining posture. It may be more apparent in states of fatigue or anxiety or when the thyroid gland is overactive. Essential tremor is slower and particularly affects the hands and arms when held out or holding a teacup. It can be embarrassing and inconvenient but it is not accompanied by any other symptoms. A similar tremor may also occur in several members of one family and also in elderly people. Alcohol reduces the intensity of essential tremor. Treatment is with beta blockers, such as propanolol. Primary orthostatic tremor affects the legs when standing still, causing unsteadiness if the position is maintained. Resting tremor is a prominent symptom of *parkinsonism. An intention tremor occurs when a patient with disease of the cerebellum tries to touch an object. The closer the object is approached the wilder become the movements.
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