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TREMBLING (synonym tremor) — the special type of an extrapyramidal hyperkinesia which is shown involuntary rhythmic stereotypic oscillating motions of various parts of a body as a result of consecutive reduction of antagonistic muscles. This symptom is characteristic of a number of diseases of a brain.

On a wedge, to features distinguish D. static, shown at rest; dynamic, arising at autokinesias (intentsionny, kinetic D.); mixed — the statodinamichesky D. appearing both at rest and at autokinesias. Distinguish D. on the frequency of reductions (from 1 — 2 fluctuations to 8 — 12 fluctuations in 1 sec.), on amplitude (from shares of centimeter to several centimeters), on topography (D. in one extremity — a monotremor, D. in a hand and a leg of one party — a hemitremor, D. in both upper or lower extremities — a paratremor, etc.), on nozol. accessories (encephalitis, injury, vascular processes, tumor, etc.); D.'s amplitude usually does not depend on its frequency. Can have character of pronation supination with rhythmic rotation of a brush and a forearm, bending and extension of fingers, reductions assignments of a shoulder etc.

Origins of D. up to the end are not studied yet. In most cases trembling hyperkinesias (see) have an organic basis. Pilot studies show that D. can be caused by irritation of kernels of a hypothalamus and part of a reticular formation about a krasnoyaderno-spinal way. Oscillating motions arise preferential on the party opposite to area of irritation, sometimes gomolateralno. Involvement of rostral departments of a reticular formation leads to a rhythmic hyperkinesia of the person, language, a neck, and lower parts of a krasnoyaderno-spinal way and a reticular formation — to D. trunks. Frequency of trembling fluctuations does not depend on the frequency of the irritating current.

The mechanism D. is explained with existence of a feed-back in systems of an innervation of muscles that leads to their self-excitation and implementation of a hyperkinesia. Is the cornerstone the synchronization of processes of excitement arising under the influence of the «pacemaker» located in a trunk of a brain and a cerebellum. As show elektromiografichesky researches, the nadsegmentarny and segmented centers, a reticular formation of a trunk of a brain influencing a functional condition of gamma cells of front horns of a spinal cord take part in D.'s education.

Assume the following biochemical, D. Sushchestvuyet's bases the concept about hypersensitivity to acetylcholine of the damaged structures of a brain responsible for emergence of. Confirmation of this concept is D.'s weakening under the influence of cholinolytic substances. Consider that cholinergic mechanisms D. arise also in connection with disturbance of system acetylcholine — cholinesterase, put strengthening of cholinergic reactions in communication with decrease in content of cholinesterase in subcrustal kernels.

Static D. is characterized by existence of fluctuations in rest, i.e. out of any reduction of muscles. In this case amplitude of a tremor small or average, the frequency of 3 — 8 fluctuations in 1 sec. of D. usually is not followed by changes of a muscle tone. It is a consequence of various processes operating on trunk departments of a brain (an injury, a tumor, an infection and so forth). Static D. can cover separate parts of a body (a monotype, segmented type), a half of a body (gemitip), all body and extremities (generalized type). It is sometimes strictly localized — only the mandible shivers, the head etc. of D. of the head can have the nature of «denial» (the movements are made in the horizontal plane — «no») or «statements» (the movements are made in the vertical plane — «yes»). Also more difficult movements by the head, napr, rotational can be observed. Static D. tends to accrue at a zazhmurivaniye of eyes that is explained by switching off of the visual reception braking activity of the excited center; it decreases or disappears at autokinesias (a tremor of rest). However if in patol, process joins a cerebellum and there are diskoordination, D. can be found also at the active movements, turning into an intentsionny tremor.

T. lakes, treat characteristic signs of static D. rhythmic fluctuations at rest, the termination of a hyperkinesia at autokinesias, resistance of symptoms, sometimes bent to a progrediyentnost. In most cases D.'s combination to other symptoms of defeat of cerebral hemispheres, cranial nerves, a spinal cord comes to light. All these data help definition topics patol, the center.

Typical static D. is observed at trembling paralysis (see) and syndromes of parkinsonism. Such D. is localized both in distal, and in proximal departments of extremities, but a thicket in distal. One of characteristic manifestations of such distal hyperkinesia — the localized D. of a brush in the form of «the account of coins», «rolling pills». The tremor extends to hands, a mandible, the head, the picture of a hemitremor is often observed (gemiparkinsonizm), during the progressing of process there comes the generalized tremor. The initial phase of autokinesia stops or considerably reduces D., however if at autokinesia the extremity accepts any certain fixed pose, D. renews, is frequent with a bigger force. Parkinsonicheskoye D. amplifies at negative emotions (see. Trembling paralysis , Parkinsonism ).

Dynamic (intentsionny, kinetic) D. appears at autokinesias and depends on defeat of structures of a cerebellum and its bonds; especially often it meets at multiple sclerosis (see). Dynamic D. has various expressiveness — from small tolchkoobrazny movements to large, with a big amplitude of oscillations. It comes to light tests on coordination — paltsenosovy and calcaneal and knee.

The mixed, statodinamichesky D. is characterized by a combination described manifestation.

Can be the only manifestation by the person nozol, the form which received the name «hereditary trembling» (before it essential, family, idiopathic, emotivny D., a tremofiliya, neurosis of trembling called). Consider that this disease of a hereditary origin, it is transferred on autosomal dominantly type, occurs at members of one family or in several of its generations. At this disease is intermediate between a tremor of rest and intentsionny. Begins, as a rule, with muscles of upper extremities, then it passes to a neck and the head (a tremor of hands, necks, the head on type «is not present» or «yes»), can pass to a mandible, lips. Less often hereditary D. goes upside-down: begins with a neck and the head, and then extends to hands. Reductions at this D. rather bystry — about 8 — 10 fluctuations in 1 sec., are sometimes more rare — 3 — 5 in 1 sec., also more rare fluctuations — 4 — 5 in 1 min. are described. The tremor amplifies at emotions, changes during the day that was the cause of wrong allocation of «emotional trembling» in the isolated form.

Hereditary D.'s beginning often matches youthful age (16 — 18 years), sometimes later; at the same time the symmetric tremor can be hardly noticeable, disappears for a short time, and further for 3 — 7 years becomes resistant. In some cases hereditary D. can be shown for the first time at late age. However it must be kept in mind that there is an independent form of senile D. connected with atherosclerosis of vessels of a brain. In this case also other symptoms of vascular damage of a brain meet.

— the main symptom hepatocerebral dystrophy (see), its trembling form. It has statodinamichesky character (it is observed at rest and at autokinesias). It is noted most often in hands, then extends to speech muscles, the head, a trunk. This form D. is quite often accompanied by muscle tension. The trembling movements are peculiar — 3 — 4 fluctuations in 1 sec., amplitude is more, than at other types of a tremor.

Can quite often be observed at endogenous intoxications (diabetes, uraemia, a thyrotoxicosis, etc.). The thyrocardiac tremor develops along with other symptoms of a thyrotoxicosis (an enlargement of the thyroid gland, disturbance of exchange etc.). D. a century, fingers of outstretched arms, sometimes the heads is noted (see. Thyrotoxicosis ). Trembling is small, the high frequency, small amplitude, very labilno. Disappears at elimination of a thyrotoxicosis. Can cause various exogenous intoxications (alcoholism, a morphinism, poisonings with mercury, lead, etc.). Alcoholic D. is concentrated in fingers of hands, the head, expressed in more morning, on an empty stomach, disappears or decreases after food and after alcohol intake.

Identification of the nature of D. at other intoxications can be difficult only at not clear anamnesis.

Organic forms D. need to be differentiated with functional. Can be display of neurosis, at the same time there are a persistence and fixing of a stereotype in the motive sphere. In cases of hysteria imitation of trembling hyperkinesias takes place. Helps differential diagnosis of organic forms D. electromyography (see).

It is necessary to remember a possibility of emergence fiziol. After the considerable muscular tension, a raising of weights, exhaustions, coolings, at affect of fear and other heavy sincere experiences (an emotional tremor). Usually fiziol. Is followed by a labile state of the vegetovascular sphere, appears suddenly and also suddenly disappears. Its emergence is connected with change of neurodynamics and humoral processes. Fiziol, the tremor needs to be distinguished from manifestations it is erased the proceeding parkinsonism or hereditary.

The research D. is conducted by special methods. D.'s registration can be carried out by means of filming by the slow motion method: high frequency of shooting with the slowed-down projection of the finished shooting shots disclosing the nature of movements. There are specially designed tremograf registering a hyperkinesia in three planes. And its dynamics are studied also by means of the dark photo. The shining bulbs fix on certain segments of an extremity which participate in D. (a finger, a forearm, a shoulder). In the dark room the shining fluctuations at great patience photograph on a film.

Strongly the electromyography entered practice of a research of trembling hyperkinesias. Using various speeds of record of potentials of muscles, it is possible to make idea of the quantitative and qualitative characteristic of rhythmic hyperkinesias.

D.'s treatment shall be directed to treatment of a basic disease. D.'s reduction can occur after use of cholinolytic means, sedative and anticonvulsant drugs. In some cases the positive effect is reached by means of stereotaxic operations (see. Stereotaxic neurosurgery ).

See also Hyperkinesias .

Bibliography: Granite P. Bases of regulation of movements, the lane with English, M., 1973, bibliogr.; The multivolume guide to neurology, under the editorship of G. N. Davidenkova, t. 2, page 133, M., 1962; Petelin L. S. Extrapyramidal hyperkinesias, M., 1970, bibliogr.; Glees P. Morphologie und Physiologie des Nervensystems, S. 249, Stuttgart, 1957; Wartenberg R. Neu-rologische, Untersuchungsmethoden in der Sprechstunde, Stuttgart, 1955.

L. S. Petelin.