From Big Medical Encyclopedia

MYOCLONIA (myoclonia; grech, mys, my[os] a muscle + klonos turmoil, a crush, the movement) — one of types hyperkinesias , characterized by sudden, bystry reductions of separate muscles or groups of muscles. The term was offered by N. Friedreich in 1881. Together with M. miokimiya — reductions only of a part of a muscle are observed quite often.

On the manifestations M. differ in a big variety that extremely complicates their classification. In different cases of M. can have various frequency, amplitude, a rhythm, localization, the motive effect can be absent or be expressed in various degree. The myoclonic hyperkinesia can cover almost all muscles of a body or be limited only to one muscle, quite often long instep support, in some cases M. remain and during sleep.

M are observed at many diseases of a brain: encephalitis of various etiology, a thicket epidemic and tick-borne, leukoencephalites, a watering can dystrophies, a myoclonic form of an amaurotic idiocy, hepatocerebral dystrophy and other diseases of a nervous system with preferential defeat of extrapyramidal system, at lead and other intoxications, in the course of treatment by the drugs L-dofy, at vascular damages of a brain, etc. One of forms is the velopalatinny M. (a nystagmus of a soft palate) connected with disturbance of blood circulation in trailer branches of an upper cerebellar artery.

On the basis of results of pathoanatomical researches the opinion that velopalatinny M. is caused by defeat of a gear kernel, red kernel, olives of a myelencephalon and their bonds is expressed. At this form constants, with a frequency of 1 — 4 time a second, rhythmical reductions of a soft palate, a throat, throat are observed, nek-ry patients have also M. of language, persons, diaphragms.

In addition to the specified symptomatic M., there are diseases, at to-rykh M. is the main, their quite often only manifestation. The multiple paramyoclonus described by N. Friedreich concerns to them, for to-rogo the visible in the same way repeating simultaneous reductions of antagonistic muscles with lack at the same time of motive effect are characteristic. At family the nystagmus myoclonia, the described Lenobl and Obino (E. A. Lenoble, E. Aubineau), is observed, except M. and a nystagmus, decrease in intelligence. Sharp attacks of a widespread myoclonic hyperkinesia are characteristic of the family M. described by S. N. Davidenkov, to-rye arise only under the influence of unexpected tactile, visual, acoustical stimulations. For the family localized M. described by R. A. Tkachyov, asynchronous, spasmodic twitchings of the same muscles are characteristic.

There is no specific treatment of M., treatment of the basic disease which caused M is carried out.

Bibliography: M. B. crawl and F e d about r the island and E. A. Main neuropathological syndromes, M., 1966; The Multivolume guide to neurology, under the editorship of G. N. Davi-denkova, t. 7, page 390, M., 1960.

R. A. Tkachyov.