tremor (trem'or) (tre'mor) [L. tremor, a shaking]
1. A quivering, esp. a continuous quivering of a convulsive nature.
An involuntary movement of a part or parts of the body resulting from alternate contractions of opposing muscles. See: subsultus
Tremors may be classified as involuntary, static, dynamic, kinetic, or hereditary. Pathological tremors are independent of the will. The trembling may be fine or coarse, rapid or slow, and may appear on movement (intention tremor) or improve when the part is voluntarily exercised. It is often caused by organic disease; trembling may also express an emotion (e.g., fear). All abnormal tremors except palatal and ocular myoclonus disappear during sleep.
action tremorIntention tremor.
The visible tremor exhibited by alcoholics.
An intention tremor of 3 to 5 Hz frequency, associated with cerebellar disease.
A tremor in which oscillations are relatively slow.
A tremor that resembles tremors of paralysis agitans.
enhanced physiological tremor
An action tremor associated with catecholamine excess (e.g., in association with anxiety, thyrotoxicosis, hypoglycemia, or alcohol withdrawal). It may occur as a side effect of drugs (e.g., epinephrine, caffeine, theophylline, amphetamines, levodopa, tricyclic antidepressants, lithium, and corticosteroids).
A benign tremor, usually of the head, chin, outstretched hands, and occasionally the voice, that is to be differentiated from the tremor of Parkinson's disease. Unlike Parkinson’s disease, essential tremor does not cause or presage other neurological complications. Essential tremor, which is made worse by anxiety or action, is usually 8 to 10 cycles per second and that of parkinsonism 4 to 5. Postural tremors occur when the patient tries to hold his hands in a particular position (e.g., when the hands are outstretched). Kinetic tremors occur during purposeful movement (e.g., during finger-to-nose testing). Essential tremor affects 5 to 10 million adults and some children in the U.S. and is probably the most common movement disorder. Its incidence increases with age. In essential tremor, there is usually a family history. The medicines effective in treating parkinsonism have no effect on essential tremor.
Patients with essential tremor often require no treatment other than reassurance. They should avoid stimulants, like caffeine or pseudoephrine, which make trembling worse, and they should rest when tremors are especially prominent. Medications commonly used to treat essential tremor include beta blockers, anticonvulsants, benzodiazepines, and botulinum toxin injections. Tremors that are exceptionally troubling to patients can also be suppressed by thalamic stimulation or surgical excision of the thalamus.
A tremor indistinguishable from essential tremor in its clinical manifestation. Unlike essential tremor, it is inherited as an autosomal dominant trait.
A tremor caused by consecutive contractions of separate muscular fibrillae rather than of a muscle or muscles.
A rapid tremor.
A tremor continuing after voluntary motion has ceased.
Hunt's tremor See: Hunt's tremor
A fine tremor occurring in hysteria. It may be limited to one extremity or generalized.
A tremor exhibited or intensified when attempting coordinated movements. Synonym: action tremor
A tremor common to paralyzed muscles in hemoplegia when attempting voluntary movement.
Slight oscillating muscular contractions in rhythmical order.
A resting tremor of the fingers and hands, often called a pill-rolling tremor, that is suppressed briefly during voluntary activity. The tremor disappears during all but the lightest phases of sleep.
A tremor occurring in normal individuals. It may be transient and occur in association with excessive physical exertion, excitement, hunger, fatigue, or other causes. See: enhanced physiological tremor
A tremor present when the involved part is at rest but absent or diminished when active movements are attempted. Synonym: static tremor
A form of benign essential tremor found in individuals older than 60, marked by rapid, alternating movements of the upper extremities that occur at a frequency of about 6 cycles/sec.
static tremorRest tremor.
Trembling of the limbs or of the body when making a voluntary effort. It is seen in many cerebellar diseases.