Nervous tick

Tics in typical cases are short, relatively elementary, stereotyped, normally coordinated, but inappropriately made movements that can be suppressed by willpower for a short period of time, which is achieved at the cost of increasing emotional tension and discomfort.

The term "tick" in practical neurology is often used as a phenomenological concept for any redundant and obscure movements, especially in the face of dyskinesias. Such a broad interpretation of teak is illegal, as it creates only confusion in terminology. Among the known hyperkinetic syndromes (chorea, myoclonus, dystonia, tremor, etc.), tick is an independent phenomenon and in typical cases is characterized by well-defined clinical manifestations, knowledge of which sufficiently reliably protects the physician from diagnostic errors. Nevertheless, syndromic diagnosis of tics is sometimes very complicated due to their phenomenological similarity with the trochaic motions or myoclonic twitching, and in some cases also with dystonic or compulsive movements. Sometimes tics are mistakenly diagnosed with stereotypes, habitual bodily manipulations, hyperactive behavior, start-up syndrome. Since the diagnosis of tics is always exclusively clinical, it is advisable to dwell more on their characteristic features.

Ticks are repetitive stereotyped movements that result from the sequential or simultaneous contraction of several muscle groups. Ticks can be fast (clonic) or somewhat slower (dystonic). Most often, ticks involve the face, neck, upper limbs, less often - the trunk and legs. Sometimes tics are manifested by vocalizations, for example, involuntary coughing or snorting. Tikam usually precedes a feeling of discomfort or imperative need to make a move. Unlike chorea, myoclonia or tremor, tics can be arbitrarily detained for a short period of time. Intellect in patients with tics usually remains safe, there are also no other pyramidal or extrapyramidal symptoms. In many patients, tics are combined with obsessive-compulsive disorder.

[1], [2], [3], [4]

Classification and causes of tics

• Primary (idiopathic): sporadic or family ticosis hyperkinesis.
  • Transit ticks.
  • Chronic tics (motor or vocal).
  • Chronic motor and vocal tics (Tourette's syndrome).
• Secondary tics (turettism).
  • In hereditary diseases (Huntington's chorea, neuroacanthosis, Gallervorden-Spatz disease, torsion dystonia, etc.).
  • With acquired diseases [craniocerebral trauma, stroke, epidemic encephalitis, developmental disorders (autism, impaired mental maturation), intoxication (carbon monoxide), iatrogenic (neuroleptics, psychostimulants, anticonvulsants, levodopa).

[5], [6], [7], [8], [9], [10]

Primary (idiopathic) tics

Transit ticks are usually referred to as a state where single or multiple tics are observed for at least 2 weeks, but not more than 1 year. Tics are manifested not only by appropriate movements (motor tics), but also by certain voice phenomena (vocal tics). Both motor and vocal tics, in turn, are divided into simple and complex ticks.

• Simple motor tics - short isolated movements, such as blinking, twitching of the head or shoulder, wrinkling of the forehead and similar elementary movements.
• Complex (complex) motor tics are manifested more complexly constructed and coordinated movements in the form of a series of linked motions reminiscent of plastic action or even more complex ritual behavior.
• Simple vocal ticks include sounds such as wheezing, grunting, mooing, sniffing, snorting and the like, or screaming individual sounds and screaming.
• Complex vocal tics have a linguistic meaning and contain full or truncated words and, in addition, include such vocal phenomena as echo- and coprolalia. Echolalia - the repetition of patients with words or phrases pronounced by another person (the repetition of the speaker of his own last word was called palalalia). Coprolalia - shouting or uttering obscene or obscene words (from the lexicon of profanity).

Motor tics initially appear as single movements in the face (single tics), over time they begin to appear in many regions of the body (multiple ticks). Some patients describe the prodromal sensations of discomfort in one or another part of the body (sensory tics), from which they try to get rid of by tickling this part of the body.

The motor pattern of ticic hyperkinesis is very specific and difficult to confuse with any other hyperkinetic syndrome. The course of the disease also differs no less than characteristic features. First of all, the appearance of tics is typical for the first decade of life, and most children fall ill at the age of 5-6 years (although variations from 3-4 to 14-18 years are possible). In the age period of childhood this stage is called psychomotor development. Violation of maturation of the psychomotor sphere is considered one of the factors contributing to the occurrence of tics.

At first, tics appear imperceptibly for the child and parents. Only as they are fixed in behavior, parents and educators begin to pay attention to them. For a long time tikoznye movements do not cause children any inconveniences and do not burden them. The child surprisingly "does not notice" his ticks. As a rule, the parents' fears are a direct reason for contacting the doctor.

The most typical beginning of tics in the face, especially localization in the region of the circular muscles of the eyes and mouth. Tykoznye movements consist in the increased blinking (the most frequent variant of a debut of tics), wink, squinting, wrinkling of a forehead, etc. There may be twitching of the angle of the mouth ("smirks"), the wings of the nose, frowning, stretching the lips, grinning, clenching the teeth, licking the lips, sticking out the tongue, etc. With the other localization of tics, they are manifested by the movements of the neck (head twists, its tipping over and other, more complex flexures of the muscles of the shoulder girdle), as well as the muscles of the trunk and extremities. Here it should be noted that in some patients tics are manifested by slower, perhaps to say "tonic" movements that resemble dystonia and even are denoted by a special term - "dystonic tics". There is another version of ticks, which we once called quick ticks; they are manifested by rapid, sometimes rapid movements (jerking the shoulders, shaking, short jerky movements to the type of flinches, leads, leads, jerky movements in the muscles of the neck, trunk, hands or feet). Complex motor tics sometimes resemble actions, such as "dropping hair from the forehead", "loosening the neck from a tight collar" or a more complex motor behavior in which tick movements are difficult to isolate from compulsive behavior that strikes with its strange and ornate plastic, sometimes epatic and attracting attention. The latter is especially characteristic of Tourette's syndrome.

At the heart of any tick, simple or complex, is the participation of several functionally related muscles, so the motor act in tick appears to be an appropriate action. Unlike other classical forms of violent movements (chorea, ballistics, myoclonus, etc.), ticotic movements are characterized by harmonious coordination, which is normally inherent in voluntary movements. For this reason, tics less disturb motor behavior and social adaptation compared to other hyperkinesis (social disadaptation in Tourette's syndrome is associated with other specific manifestations of this syndrome or severe comorbid disorders). Tics are often similar to natural in origin, but exaggerated in their expressiveness and inappropriate for place and time (inappropriate) gestures. This corresponds to a number of other facts: sufficiently high-willed control over the tics, the ability to replace (if necessary) the habitual tick movement with a completely different motor act, the ability to quickly and accurately reproduce tics.

The flow of tics is so peculiar that it carries in itself the most important diagnostic information. Recall that in cases where patients well remember the onset of the disease, they usually indicate facial tics as the first symptom of the disease. In the future, hyperkinesis gradually "overgrows" with other tick movements, disappearing into some and appearing in other muscle groups. For example, ticks can begin because of rapid blinking, which, periodically renewing, lasts 2-3 months, and then spontaneously passes, but it is replaced by periodic movement of the corner of the mouth or the tongue (head, hand, etc.), which, in in turn, lasting for a while (weeks, months), is replaced by new ticotic movements. Such a step-by-step migration of ticotic movements in different muscle groups with periodic changes in the localization of hyperkinesis and its motor pattern is very characteristic and has an important diagnostic significance. At each stage of the disease, as a rule, 1 or 2 ticotic movements predominate and there are no (or less frequent) movements that were observed at the previous stage. Relatively more stable is the facial localization of tics. Thus, the disorder not only debuts from the facial muscles, but also in a certain sense "prefers" them to other segments of the body.

Ticks can be quite heavy, causing physical or psychosocial maladaptation. But in most cases they are relatively easy and represent a psychosocial problem. It is established that approximately 1 person out of 1000 suffers from this disease. There are family cases of Tourette's syndrome, which testify to autosomal dominant inheritance with incomplete penetrance and variable expressiveness. In family members of the patient, the alleged genetic defect may be manifested by chronic motor tics or obsessive-compulsive disorder. The gene or the genes of Tourette's syndrome have not been identified to date.

Chronic tics (motor or vocal)

Appearing in childhood, the disease tends to prolonged (sometimes throughout life) flow with wave-like exacerbations and remissions: periods of pronounced ticks alternate with periods of their complete or partial remission. Tics that periodically manifest over 12 months are called chronic motor or vocal tics. Sometimes ticks spontaneously stop in the puberty or post-pubertal period. If they do not pass during this critical period, they usually remain for an indefinitely long time. Nevertheless, the predominant trend is, apparently, an improvement in the state. After many years, about a third of the sufferers are still released from ticks, another third marks a certain improvement in their condition, the remaining part of patients notes the relatively steady course of ticosis hyperkinesis. Tics are usually intensified by the influence of psychotraumatic situations, stresses, prolonged emotional stress and, on the contrary, decrease in a situation of emotional comfort, relaxation and disappear during sleep.

[11], [12]

Tourette's syndrome (chronic motor and vocal tics)

If earlier idiopathic tics and Tourette's syndrome were considered as diseases of fundamentally different nature, today many neurologists tend to regard them as different manifestations of the same suffering. Recently, the clinical criteria of Tourette's syndrome were such manifestations as coprolalia and the so-called autoaggressive tendencies in behavior (tics in the form of strikes on surrounding objects and, more often, on the body). It has now been established that coprolalia can be transient in nature and occurs in less than half of patients with Tourette's syndrome. Modern diagnostic criteria for Tourette's syndrome are as follows.

• Presence of multiple motor tics plus 1 or more vocal tics for some time (not necessarily simultaneously).
• Multiple occurrence is ticked throughout the day, usually in batches, almost every day for a period of more than 1 year. At this time there should be no tick-free episodes lasting more than 3 consecutive months.
• Noticeable distress or significant deterioration of the patient's social, professional or other activities.
• The onset of the disease is under the age of 18 years.
• The revealed disturbances can not be explained by the influence of any substances or general disease.

In recent years, these diagnostic criteria (DSM-4) have been supplemented with criteria for a reliable and probable Tourette syndrome. A reliable diagnosis corresponds to the above diagnostic requirements. The diagnosis of Tourette syndrome is considered probable if the tics do not change with time and have a persistent and monotonous course or the patient does not meet the first point of the above diagnostic requirements.

An important feature of the clinical manifestations of Tourette's syndrome is also that it is often combined with certain behavioral disorders, the list of which includes obsessive-compulsive disorders, the syndrome of minimal brain dysfunction (hyperactive behavior, attention deficit disorder), impulsiveness, aggressiveness, anxious, phobic and depressive disorders, self-harm, low frustration tolerance, insufficient socialization and low self-esteem. Obsessive-compulsive disorders are noted in almost 70% of patients, they are considered as one of the most frequent comorbid disorders. Nearly every second patient with Tourette's syndrome is diagnosed with attention deficit hyperactivity disorder, with the same frequency of self-harm. Some researchers believe that these comorbid behavioral disorders are nothing more than a phenotypic manifestation of Tourette's syndrome, most of which develops against a background of hereditary predisposition. It is believed that Tourette's syndrome occurs much more often than is diagnosed, and that the population is dominated by patients with mild and non-adaptive manifestations of the disease. It is also assumed that behavioral disorders may be the only manifestation of Tourette's syndrome.

In contrast to obsessive movements, the desire to exercise a tick is either poorly understood in general, or is realized not as a pathological phenomenon, but as a physiological need and without that personal arrangement that is characteristic of the corresponding psychopathy. Unlike tics, compulsions are accompanied by obsessions and are often performed in the form of rituals. It is important to note that true obsessive-compulsive disorders are comorbid with respect to tic disorders. Moreover, in some patients with Tourette's syndrome, tics and compulsions represent a single behavioral phenomenon, manifested by a bright and unusual clinical picture, in which it is not always easy to isolate its main constituent elements.

Secondary tics (turettism)

This variant of a tick syndrome is observed much less often than primary forms, it is possible both with hereditary (Huntington's chorea, neuracacitosis, Gallervorden-Spatz disease, torsion dystonia, chromosomal abnormalities, etc.) and acquired (craniocerebral trauma, stroke, encephalitis, disorders development, intoxication, iatrogenic forms) diseases.

In these cases, along with the typical clinical manifestations of the underlying disease (for example, Huntington's chorea, dystonia, neuroleptic syndrome, etc.), the phenomenon of vocalization and tick movements (in addition to the main hyperkinesis or other neurological manifestations) take place. The main method of diagnosing tics is also their clinical recognition.

Neurochemical changes

To date, only a few patients with Tourette's syndrome have been able to carry out a pathomorphological examination, and no specific pathomorphological or neurochemical changes have been identified. At the same time, several post-mortem neurochemical studies have noted changes in the activity of the dopaminergic system. Recently, a neuroimaging study of monozygotic twins with Tourette's syndrome noted that the twin with more pronounced clinical manifestations had higher dopamine D2 receptors in the striatum. Using MRI, it was found that in patients with Tourette's syndrome, the normal asymmetry of the right and left caudate nuclei was lost. The data of functional MRI and PET-activation studies indicate dysfunction of the orbitofrontal-caudate circle.

Relatively recently it was noted that in some persons with post-streptococcal chorea of Sidengam, in addition to the actual chorea, tics and obsessive-compulsive disorder are detected. In this regard, there were suggestions that some cases of tics have an autoimmune genesis and are associated with the formation of antibodies to the caudate nucleus antigens, which is provoked by streptococcal infection.