Seizures of immobility or "freezing". Causes and symptoms

States of permanent or periodic immobility, "freezing", akinesia, aspontaneity, areactivity of various origins are referred to as the so-called negative neurological symptoms. Their pathogenesis, etiology and clinical classification have not yet been fully systematized. They may have subcortical (extrapyramidal), frontal (motivational), brainstem (akinetic), cortical (epileptic), neuromuscular (synaptic) origin. Finally, states of immobility may be a manifestation of psychotic disorders or conversion disorders. All these diseases, as a rule, are manifested by other characteristic clinical symptoms and paraclinical deviations in EEG, MRI, electrolyte metabolism parameters, glucose metabolism, neuropsychological tests, as well as (primarily) in the corresponding changes in neurological and mental status. Analysis of clinical manifestations is of priority importance in most of the above cases.

The main clinical forms of attacks of immobility or "freezing":

A. Freezing episodes (freezing, motor block, solidification).

1. Parkinson's disease.
2. Multiple system atrophy.
3. Normal pressure hydrocephalus.
4. Dyscirculatory (chronic ischemic) encephalopathy.
5. Primary progressive freezing dysbasia.

B. Epilepsy.

C. Cataplexy.

D. Catalepsy (in the picture of mental illnesses)

E. Psychogenic areactivity.

F. Attacks of immobility during hypoglycemia (diabetes mellitus).

G. Paroxysmal myoplegia.

1. Hereditary periodic paralysis.
2. Symptomatic periodic paralysis (thyrotoxicosis; hyperaldosteronism; gastrointestinal diseases leading to hypokalemia; hypercorticism; hereditary adrenal hyperplasia; excessive secretion of antidiuretic hormone; kidney disease. Iatrogenic forms: mineralocorticoids, glucocorticoids, diuretics, antibiotics, thyroid hormones, salicylates, laxatives).

A. Freezing episodes (freezing, motor blocks, freezing)

Parkinson's disease is one of the most typical diseases in the clinical manifestations of which freezing episodes are often encountered. Freezing episodes often develop during the "offw" period, that is, the "switch-off" period (but can also be observed in the "on" period). They are most clearly manifested in walking. Patients begin to experience difficulties when trying to start moving ("feet stuck to the floor" symptom). It is difficult for the patient to take the first step; it is as if he cannot choose the foot with which to start moving. A characteristic stamping on the spot develops. In this case, the center of gravity of the body begins to move forward in the direction of movement, and the legs continue to stamp on the spot frequently, which can lead to the patient falling even before the start of movement. Another situation in which freezing episodes are often detected is associated with torso turns while walking. Torso turns while walking are a typical risk factor for a patient falling. A narrow space, such as a door in the patient's path, can provoke freezing. Sometimes freezing occurs spontaneously without external provoking factors. The occurrence of freezing episodes increases the risk of the patient falling. The presence of motor blocks is usually accompanied by deterioration of postural reflexes, aggravation of dysbasia. Physiological synergies are lost, instability develops when walking and standing, it is difficult for patients to prevent falls. Freezing can affect any motor functions, including various movements during self-care (the patient literally freezes during some action), as well as walking (sudden stops), speech (a long incubation period appears between the doctor's question and the patient's answer) and writing. The presence of concomitant clinical manifestations of parkinsonism (hypokinesia, tremor, postural disorders) complement the typical picture of the appearance of a patient with parkinsonism.

The diagnosis is made clinically. The frequency of freezing episodes correlates with the duration of the disease and the duration of treatment with dopa-containing drugs.

Multiple system atrophy (MSA) can also manifest itself, in addition to other typical syndromes (cerebellar ataxia, progressive autonomic failure, parkinsonism syndrome), with freezing episodes, the pathogenesis of which is apparently also associated with progressive parkinsonism syndrome within the framework of MSA.

In addition to dementia and urinary incontinence, normal pressure hydrocephalus also manifests itself in gait disturbances (Hakim-Adams triad). The latter are called gait apraxia. Disproportionate steps, lack of coordination between the movements of the legs and body, dysrhythmic, unstable, uneven and unbalanced walking are revealed. The patient walks uncertainly, with noticeable caution and slower compared to a healthy person. Freezing episodes may occur. A patient with normal pressure hydrocephalus may outwardly resemble a patient with Parkinsonism syndrome, which often serves as a reason for a diagnostic error. But it is useful to remember that there are rare cases of the development of true Parkinsonism in normal pressure hydrocephalus syndrome, in which freezing episodes may be observed even more so.

Etiology of normal pressure hydrocephalus: idiopathic; consequences of subarachnoid hemorrhage, meningitis, traumatic brain injury with subarachnoid hemorrhage, brain surgery with bleeding.

Differential diagnosis of normal pressure hydrocephalus is carried out with Alzheimer's disease, Parkinson's disease, Huntington's chorea, and multi-infarct dementia.

To confirm the diagnosis of normal pressure hydrocephalus, CT is used, less often - ventriculography. A test has been proposed to assess cognitive functions and dysbasia before and after cerebrospinal fluid extraction. This test also allows selecting patients for shunt surgery.

Discirculatory encephalopathy, especially in the form of a multi-infarction condition, is manifested by various motor disorders in the form of bilateral pyramidal (and extrapyramidal) signs, oral automatism reflexes and other neurological and psychopathological disorders. In the lacunar condition, there may also be a gait of the "marche a petits pas" type (small, short, irregular shuffling steps) against the background of pseudobulbar paralysis with swallowing disorders, speech disorders and Parkinson-like motor skills. Here, episodes of freezing during walking may also be observed. The above-mentioned neurological manifestations are supported by the corresponding CT or MRI picture, reflecting multifocal or diffuse damage to brain tissue of vascular origin.

Primary progressive freezing dysbasia is described as an isolated single symptom in elderly people (60-80 years and older). The degree of freezing gait disorders varies from isolated motor blocks with external obstacles to severe disorders with complete inability to start walking and requiring significant external support. Neurological status usually does not reveal deviations from the norm, with the exception of frequently detected postural instability of varying degrees of severity. There are no symptoms of hypokinesia, tremor and rigidity. Blood and cerebrospinal fluid tests do not reveal abnormalities. CT or MRI are normal or reveal mild cortical atrophy. Therapy with levodopa or dopamine agonists does not bring relief to patients. Gait disorders progress without the addition of any other neurological symptoms.

V. Epilepsy

Epilepsy with seizures of "freezing" is typical for minor seizures (absences). Isolated absences are observed exclusively in children. Similar seizures in adults should always be differentiated from pseudo-absences in temporal epilepsy. Simple typical absence is clinically expressed in a sudden, very short-term (several seconds) loss of consciousness. The child interrupts the speech he started, reading a poem, writing, moving, communicating. The eyes "stop", the facial expression is frozen. General motor skills "freeze". In simple absences, the EEG reveals symmetrical peak-wave complexes with a frequency of 3 per second. All other forms of absences with other clinical "additions" or other EEG accompaniment are classified as atypical absences. The end of the seizure occurs instantly, leaving no discomfort or stunning. Children often continue the activity they started before the seizure (reading, writing, playing, etc.).

C. Cataplexy

Cataplexy in narcolepsy manifests itself in attacks of sudden loss of muscle tone, which is provoked by emotions (laughter, joy, less often - surprise, fear, resentment, etc.), less often - by intense physical exertion. Partial attacks of cataplexy are most often observed, when loss of tone and weakness are observed only in some muscles: the head droops forward, the lower jaw drops, speech is upset, knees bend, objects fall out of the hands. In generalized attacks, complete immobility occurs, the patient often falls. A decrease in muscle tone and the disappearance of tendon reflexes are observed.

D. Catalepsy

Catalepsy (in the picture of mental illnesses with catatonic syndrome) is characterized by the phenomenon of "wax flexibility", given unusual "freezing poses", "strange motor skills" against the background of gross mental disorders in the picture of schizophrenia (DSM-IV). Catatonia is a syndrome that rarely has a neurological origin: it is described in non-convulsive forms of epileptic status ("ictal catatonia"), as well as in some gross organic lesions of the brain (brain tumor, diabetic ketoacidosis, hepatic encephalopathy), which, however, requires further clarification. Much more often, catatonic stupor develops in the picture of schizophrenia.

E. Psychogenic unresponsiveness

Psychogenic unresponsiveness in the form of freezing attacks can sometimes be observed in the picture of pseudo-seizures that imitate an epileptic seizure or fainting (pseudo-syncope) or proceed entirely in the form of a state of immobility and mutism (conversion hysteria). The same principles of clinical diagnostics that are used to diagnose psychogenic paralysis, seizures and hyperkinesis are applicable here.

F. Attacks of immobility during hypoglycemia (diabetes mellitus)

May be observed as a variant of reversible hypoglycemic coma.

G. Paroxysmal myoplegia

Depressive stupor in the picture of severe psychotic depression usually does not have the character of an attack, but proceeds more or less permanently.

Conditions resembling short "freezings" or "freezings" can sometimes be observed in hyperekplexia syndrome (see the section "Startle syndrome").