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Related to rest tremor: physiologic tremor, action tremor


a minor earthquake
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an involuntary trembling of the entire body or parts of it. Tremors are characteristically rhythmic and stereotypic; usually they have a narrow range, most often affecting the fingers, eyelids, tongue, lower jaw, and head. In healthy subjects, tremors may be caused by muscular strain, emotional excitement, or exposure to cold. Pathological tremors may be symptoms of chronic alcoholism, thyrotoxicosis, neurotic states, acute infections, and such diseases as parkinsonism. The symptom is treated by treating the primary disease.

Eye tremor is an involuntary rapid movement of the eyeball in relation to the optic axis; its frequency is from 20 to 150 Hz, and its amplitude, from 5 to 15 seconds of arc. Visual perception itself depends to a significant degree on eye tremor, which produces constant changes in the illuminance of certain photoreceptors—that is, the photoreceptors located at the variously illuminated points of the retinal periphery. An image whose projection on the retina remains completely stable for more than a few seconds ceases to be perceived by the visual centers of the brain.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A minor earthquake. Also known as earthquake tremor; earth tremor.
Involuntary, rhythmic trembling of voluntary muscles resulting from alternate contraction and relaxation of opposing muscle groups.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The tremor, although evident, rarely resembles that of the classic pill-rolling rest tremor seen in IPD, nor does it present independently of cerebellar or autonomic features.
The classification of pure action tremor is difficult because rest tremor may be very mild and intermittent, especially when patients are treated with dopaminergic drugs.
Neurophysiologic tests may help in cases of coexistence of postural and rest tremor. We think some neurophysiologic criteria for the diagnosis of PD are useful: (1) there is rhythmic burst of rest tremor on EMG, (2) tremor frequency is stable at 4-6 Hz; (3) if postural tremor exists, there is tremor latency from rest to postural position; (4) changes of the dominant frequency peak are less than or equal to 1 hz after the weight load test; (5) there are changes in tremor amplitude after mental concentration.
Among motor symptoms and signs, the cardinal ones (bradykinesia, rest tremor, and rigidity) are mainly ascribed to the loss of dopaminergic neurons [4], but those involving posture, balance, and gait are largely secondary to degeneration of nondopaminergic pathways and significantly contribute to impairment and disability in advanced PD patients [5].
They include rest tremor, which stands among the PD cardinal signs, especially in the tremor-dominant subtype [4, 40], an action tremor named reemergent tremor, which reappears few seconds after the transition from rest to posture and has a frequency similar to that of rest tremor, essential tremor, dystonic tremor [74], and exaggerated physiological tremor [75].
The pathophysiology of rest tremor is largely unknown, but there is good evidence that it differs from that of bradykinesia and rigidity [77].
Several hypotheses, which share the view of a central rather than peripheral origin, have been suggested to explain the pathophysiology of rest tremor [32].
Butz et al., "A direct relationship between oscillatory subthalamic nucleus-cortex coupling and rest tremor in Parkinson's disease," Brain, vol.