Body scheme- a complex, generalized image of one's own body, the location of its parts in three-dimensional space and in relation to each other. This image arises in the human brain based on the perception of kinesthetic, pain, tactile, vestibular, visual, auditory and other afferent stimuli in comparison with traces of past sensory experience.

The body scheme is a necessary link in the implementation of any movements , changes poses , gait , tk. in all these cases, it is necessary to sense the initial position of the body and its parts and take into account the flow of reverse afferentation when they change. S. t. is of particular importance for the regulation of posture and movements under conditions of weightlessness.

With pathology, S.'s disorders of t. are manifested by a distorted perception of one's own body and its parts. Various types of non-recognition of parts of the body, their condition and position belong to S.'s violations of t. The most common is anosognosia - the patient's unawareness of a defect or disease state of any organ. For example, a patient with hemiplegia claims that he freely makes any movement with a sick arm or leg. There is also autotopagnosia - unawareness of the location of body parts, when the patient cannot show where his paralyzed hand is. S.'s disturbances of t. also include loss of orientation in the right and left sides of the body, a feeling of the presence of additional (false) limbs - pseudopolymelia and etc.

Peculiar sensitivity disorders are often observed: non-recognition of painful stimuli or agnosia of pain, allochyria, when the patient perceives irritation on one side of the body in a symmetrical place on the other side, a symptom of sensory inattention - the patient, with a simultaneous injection at symmetrical points of the body on both sides, perceives an injection only on one side, but does not notice him on the other, etc.

Symptoms of S.'s disturbance of t. are observed at the vascular, traumatic, tumor and other organic focal defeats capturing thalamoparietal system, most often the right hemisphere. Hemiplegia, the severe general condition of the patient, contribute to the manifestation of these disorders. Violations of S. t. usually disappear with a further deterioration in the patient's condition or, conversely,

as he emerges from a difficult state.

S.'s disorders of t. often develop simultaneously with the phenomena of derealization and depersonalization in epilepsy, schizophrenia, in the structure of phases (attacks) of a circular illness. There are pathological sensations of a change in the size and shape of the body (autometamorphopsia): in some cases, there is a feeling of a total increase or decrease in the volume or weight of the body (total autometamorphopsia), in others, there is a feeling of an increase in certain parts of the body, for example, upper or lower extremities, head (partial autometamorphopsia ). The sensation of an increase or decrease in the size of the body or its parts disappears with visual control. The appearance of S.'s disorders of t. is often accompanied by the development of a feeling of fear, anxiety.

Diagnostic value of violations of S.

t. consists in the fact that they, in combination with other focal symptoms, indicate participation in the pathological process of the thalamoparietal system and the cortex of the parietal region, usually the right hemisphere of the brain.

Bibliography: Babenkova S.V. Clinical syndromes of lesions of the right hemisphere of the brain in acute stroke, M., 1971; Badalyan L.O. Pediatric neurology, p. 81, M., 1984; Collins R.D. Diagnosis of nervous diseases, trans. from English, M., 1976; Martynov Yu.S. Nervous diseases, M., 1988; Megrabyan A.A. General psychopathology, M., 1972; Manual of Psychiatry, ed. A.V. Snezhnevsky, vol. 1, M., 1983; Handbook of Psychiatry, ed. A.V. Snezhnevsky, p. 51, M., 1985.

One of the types of disorders of the central nervous system is a violation of the perception of one's own body, or, as this disorder is also called, a violation of the body schema. For the first time this violation was described by three doctors Peak, Head and Schilder. They presented their concept of the disease as early as the beginning of the 20th century. Since then, psychiatrists have used it to describe the condition of patients who are "entangled" in their own body.

In diseases of the brain, there is an incorrect interpretation of the signals coming from receptors from different parts of the body. Normally, they fall into special areas of the brain, where he disassembles them into components and “decides” that he feels, how much he “feels” it, and where the signal actually came from. If these zones are damaged, then a condition arises in which a person cannot say exactly where, for example, he was pricked with a needle - in his right hand or left, or what size his head is.

What is a body schema disorder?

To understand this term, we turn to reference publications. They write that a violation of the body scheme is a disorder of orientation in one's own body or surrounding objects, in which the patient cannot say exactly what size, how far, from which side, etc. its limb or a specific object is located. Most often, this violation occurs when damage to the parietal lobe in the region of the interparietal sulcus, especially when the lesion is localized in the right hemisphere.

The violation of the perception of one's own body is especially pronounced in cases where there is one-sided paralysis of the body, combined with loss of sensitivity in the same half of the body and bilateral blindness with loss of visual fields on one side. People in this state cannot find their limb or indicate the place from which it begins. At the same time, they can point to the leg or consider that the arm begins to grow from the elbow or from the middle of the chest.

Some patients may be sure that they have three legs or arms, 6 fingers or 2 noses - they are not only sure of this, but they feel it. It is characteristic that all patients do not consider themselves as such, they deny the presence of paresis or paralysis and also insist on the fidelity of their sensations. Denial of one's illness is called anosognosia, and not recognizing one's own body parts is called pseudomelia.

If this pathology is combined with cerebral atherosclerosis, delirium, hallucinations, delirium may also be present, which significantly complicates the diagnosis. In this state, the patient claims that the limb does not belong to him, that his neighbors threw it in, and his own hand is in the closet, etc. There are many variations in this case.

If the patient at the same time has symptoms of paresthesia - changes in sensitivity, which are often accompanied by a feeling of crawling, numbness, tingling, then the patient includes all this in the complex of his sensations and transforms it into delusional hypotheses in which he is tortured, or he is eaten from the inside by worms. Delirium has a bright emotional coloring, therefore it has a huge number of options, depending on the characteristics of the patient's psyche and his addictions.

Also, a disorder of the body scheme may be accompanied by metamorphopsia - incorrect perception of surrounding objects, a change in the assessment of size and static. For example, a patient may look at a chair with a back, and it will seem to him that it is a stool with spiral legs, which, moreover, rotates in space and is rapidly approaching him. In some cases, surrounding objects may become small or, conversely, huge, they may seem larger in number than they actually are, they may fall on the patient, try to crush him, draw him in.

Some patients may perceive themselves both in themselves and apart from their body. At the same time, they experience the feeling that they are in their own body, but they can observe themselves from the side, as if detached.

Quite often, a violation of the body scheme is accompanied by changes in the perception of one's own size. So, patients can perceive themselves as giants who ended up in a small room, where everyone is very miniature in size. As a result, they are afraid to move so as not to crush or break anything. Some patients claim that they are so big that they need a bed for the whole room, otherwise they will not be able to fit on it, or that their head is much larger than a pillow, but now the body is gone or has become very small. That is why this disorder has another name - Alice in Wonderland syndrome.

A very important difference between psychosensory disorders and hallucinations is the distorted perception of real rather than fictional objects. In addition, the patient recognizes objects, but perceives their shape, size, distance to them incorrectly. This is the main difference between illusory and hallucinatory perceptions and psychosensory disturbances.

What is allocheiria?

The number of psychosensory disorders described in patients suffering from body schema disorder is actually much larger, but the scope of the article does not allow describing them all.

Finally, let us dwell on one more type of disorder of the psychosensory perception of one's own body - allocheiria.

This term refers to the perception of irritation from the other side of the body. It refers specifically to the hands - "allos" - from Greek it is translated as another, and "cheir" - a hand. Therefore, when irritation occurs on the right hand, the patient says that it occurs on the left hand, and vice versa. In other words, all sensations are transferred symmetrically from one hand to the other, i.e. all feeling is transferred by 180 ° - from right to left and from left to right.

In this case, there may be an incorrect indication of the place of irritation. For example, a patient has been pricked with a finger on his right hand, and he will feel that he was pricked in his left hand at the level of the forearm. Also, this disorder can be combined with hyperalgesia - a violation of temperature perception. In this case, the touch of a cold object to the hand on the right can be perceived by the patient as a touch of a hot object to the other hand.

When does allocheiria happen?

Allocheiria, as one of the types of disorders in the perception of one's own body, can be with damage to the brain, in particular the parietal lobe on the right.

Also, this disorder occurs in cerebral atherosclerosis, in the post-stroke period, when the hemorrhage affected the parietal region of the brain, with brain tumors, multiple sclerosis, certain types of epilepsy and migraine, hysteria.

BODY SCHEME- a complex synthetic image of one's own body and its parts, formed in the human brain on the basis of perception, sensation of kinesthetic, tactile, pain, vestibular, visual, auditory and other stimuli in comparison with traces of past sensory experience. The term was introduced by P. Schilder.

S. t. is important in the formation of posture and movements (see Movement, Pose, Postural reflexes), regulated by both conscious (see Consciousness) and unconscious reflex mechanisms. In space medicine, the concept of "body scheme" is used in the study of relationships in the system man - spacecraft - the surrounding space.

Physiol. S.'s basis of t. is made by the functional system integrating a stream of afferent impulses (see. Sensitivity) from own body and its parts. This functional system integrates a dynamic, three-dimensional-spatial image of the body created by current afferent impulses, and a static image of the body, a kind of set of standards of postures, body positions, acquired in ontogenesis through learning based on long-term memory.

Page of t. is formed with age, gradually; children under 5 do not yet have a fully formed body image. The page of t. is formed at the child concerning the right half of a body earlier, and soon then and concerning the left.

In a wedge, neurology and psychiatry use the concept of S.'s disturbances of t.: a syndrome of the distorted perception, sensations of the body, its size, form, weight, provision in space, state of rest or movement. Moreover, a distorted sensation of both the image of the whole body and its parts is possible.

G. Ged considered the image of the body as a unity synthesized in the cerebral cortex, due to past experience and current sensations of the subject. Petzl (O. Potzl) attached particular importance in the mechanisms of S.'s disturbances to t. to a local factor, namely, focal lesions of the parietal lobe. S. V. Babenkova on the basis of comparison a wedge, pictures of focal vascular defeats of the right and left hemispheres of a brain established that many symptoms of S.'s disturbance of t. arise at focal defeats of the right hemisphere, a cut on this basis can be considered as dominant in relation to gnosis (knowledge) of one's own body. At the heart of a pathogeny of disturbances S. of t. reversible and irreversible changes in the central nervous system, mainly in thalamoparietal system lie. Reversible changes cause transient disorders of S. t., and irreversible - persistent.

Violations of the scheme of a body at nevrol. diseases can be caused by focal lesions of the cerebral hemispheres, vascular, infectious, tumor etiology, or destructive and limiting intracranial space processes of a different origin, while lesions of the cortex of the supramarginal and angular gyri of the parietal lobe play a particularly important role. It is explained fiziol. the role of the lower parietal region of the cerebral cortex, mainly of the right hemisphere, integrating afferent impulse flows from many analyzers and thus being a polyanalyzer. The conditions for the occurrence of S.'s disorders of t. are also created by disorders of the coordinated activity of the hemispheres and the presence of cerebral symptoms.

To the most often meeting a wedge. symptoms of violations of S. t. include the following.

1. Anosognosia - unawareness of the resulting dysfunction of any organ or limb as one of the types of agnosia (see). With focal lesions of the right hemisphere of the brain, unawareness of the patient's motor disorders is often observed. So, for example, the patient can assert that normally owns extremities, to-rye are actually paralyzed; the wedge, observations of unconsciousness of blindness and disturbances of other functions are known.

2. Autotopagnosia - unawareness of the location in space of parts of one's body. As a result, the patient, for example, can look under the pillow for his paralyzed arm, which actually lies on his chest.

3. Finger agnosia - a violation of recognition, choice and correctness of showing fingers, both one's own and other people.

4. Violation of orientation in the right and left sides.

5. Pseudomelia - a false sensation of the absence (pseudoamelia) or the presence of an extra, illusory limb, sometimes several such limbs (pseudopolymelia).

6. Feeling the phantom of an amputated limb, when the victim with the removed limb continues to feel it as existing.

7. Symptoms of sensory inattention: the patient ignores the visual field of the left eye, puts on trousers only on the right leg, while stubbornly ignoring the left leg, etc.; with a simultaneous injection in symmetrical places of the right and left half of the body, an injection on the left side, while maintaining sensitivity, is not perceived, it is ignored by the patient.

8. A symptom of alienation of a paralyzed limb, in which the patient perceives it as someone else's.

Less common are other phenomena of sensory disturbances. For example, allesthesia, when, with painful irritation of a diseased limb, pain is felt in a healthy one; allochei-riya - indistinguishability of the side of the body, on which irritation is applied. Some symptoms of S.'s disturbance of t. are part of Ekaen's apractognostic syndrome (N. Hecaen, 1956), which includes left-sided spatial agnosia, autotopagnosia, dyslexia, acalculia, and is observed when the lesion is localized in the area of ​​the supramarginal, angular gyrus of the parietal lobe and superior temporal gyrus of the right hemispheres of the brain. Symptoms of S.'s disturbance of t. are included in the expanded syndrome of defeat of the right hemisphere and are quite often combined with confabulations (see. Confabulosis), pseudo-reminiscences (see. Paramnesias), euphoria (see. Psychoorganic syndrome), somnolence, automatic gesticulation, psychomotor excitement, disorientation in time. S.'s disturbances of t. at localization of the center in the left hemisphere of a brain are observed quite seldom. Violation of the right-left orientation usually manifests itself with simultaneous focal lesions of both hemispheres. In combination with symptoms of damage to the motor, sensory and reflex spheres, S.'s disorders of t. play an important role in the topical diagnosis of the lesion.

Body schema disorders in mental illness, for example, in schizophrenia, may be manifested by a distortion of the sense of the shape, size or weight of the body. At total frustration S. of t. the size, and quite often also body weight are perceived by the patient as sharply increased or decreased. In some cases, patients have a feeling that his body has increased so much that it occupies the entire room where the patient is located, or has decreased to the size of the body of a newborn; patients also claim that the body weight has increased to several hundred kilograms or feel the body is weightless. At partial disturbances of S. of t. at patients there is a feeling that separate parts of a body are extended or shortened; patients talk about an increase or decrease in the volume of the head, a thickening of the tongue, a sharp increase or decrease in one or more limbs. Disorders are more rare, at to-rykh the patient feels alienation of separate parts of a body, to-rye exist as though separately, or in representation of the patient double. In most cases, patients have a critical attitude towards S.'s disorders of t.

Violation of S. t. may be the only symptom that often occurs at the time of falling asleep or waking up, sometimes at a certain position of the body. Violation of S. t. in mental illness is possible both in the form of a stationary state, and in the form of an episode, a paroxysm. They are often combined with the phenomena of metamorphopsia and depersonalization disorders (see Depersonalization), and are also observed in the structure of complex syndromes: affective, hallucinatory-delusional, states of clouding of consciousness. In some cases, S.'s disorders of t. can acquire the character of "madeness", which allows them to be attributed to the phenomena of mental automatism (see Kandinsky - Clerambo syndrome). In these cases, there is no critical attitude to S.'s disorders of t. S.'s disorders of t. should be distinguished from the phenomena of metamorphopsias (see), at which there are changes in the perception of the size or shape of objects, as well as the surrounding space, and from the phenomena of depersonalization, at which a change in one's self is noted.

Bibliography: Babenkova S. V. Clinical syndromes of lesions of the right hemisphere of the brain in acute stroke, M., 1971; Bekhterev V. M. Pseudopoli-melia paraesthetica in the form of imaginary members, Review. psychiat., neurol. and experiment, psychol., No. 4, p. 236, 1926; M e gr and - I am N A. A. Depersonalization, Yerevan, 1962; he, General psychopathology, M., 1972; M e r about in and h R, I. Disorders of "body scheme" at mental illnesses, JI1948, bibliogr.; R about in and scientific researcher to and I am S. A. The characteristic of disturbances of the scheme of a body at diencephalic and stem defeats of infectious genesis, Zhurn. neuropath, and psychiat., vol. 68, c. 12, p. 1788, 1968, bibliography; Stolyarova L. G. and Sidorovskaya M. D. To the question of violation of the body scheme, Owls. medical, N° 3, p. 99, 1964, bibliogr.; Evolution of the functions of the parietal lobes, ed. A. S. Batueva, L., 1973; In a b i n s k i J. Contribution & l'6tude des troubles mentaux dans l'h£miplegie organique c£r6brale (anosogno-sie), Rev. neurol., p. 845, 1914; Schil-d e r P. Das Korperschema, B., 1923.

L. A. Kukuev; A. S. Tiganov (psychiatrist).

Agnosia. Object agnosia - the loss of the ability to recognize familiar objects; with other types of agnosia, individual qualities may not differ: color, sound, smell.

Violation of higher visual functions, the implementation of which is primarily provided by the occipital regions of the brain, manifests itself in visual agnosia.

With visual agnosia, the recognition of an object or its image is impaired, and the idea of ​​​​the purpose of this object is lost. The patient sees, but does not recognize an object familiar to him from past experience. When feeling this object, the patient can recognize it. And, conversely, with astereognosis, the patient does not distinguish objects by touch, but recognizes them by examining them.

Defeat can be limited to not recognizing only individual details of the object, the inability to combine individual parts into a whole. Thus, looking at a successive series of pictures, the patient understands their details, but is unable to grasp the general meaning of the entire series. May have facial agnosia prosopagnosia), in which the patient does not recognize well-known faces; does not recognize personal photographs or even himself in the mirror.

In addition to object agnosia, there may be spatial visual agnosia; when there is a violation of the perception of successive actions, spatial relationships of objects, usually with a simultaneous orientation disorder in the environment. The patient cannot imagine the well-known layout of rooms, the location of the house, which he entered hundreds of times, the location of the cardinal points on a geographical map.

When a patient without symptoms of hearing loss loses the ability to recognize objects by their characteristic sounds (for example, water pouring from a tap, a dog barking in an adjacent room, a clock strike), we can talk about auditory agnosia. Here, it is not the perception of sounds that suffers, but the understanding of their signal meaning.

As already mentioned, both hemispheres of the brain are engaged in the processing of auditory, visual, somatosensory and motor material entering the brain. But the participation of both hemispheres of the brain in this process is ambiguous. The right hemisphere of the brain is functionally connected with the perception and processing of non-verbal (non-verbal) material. It is characterized not so much by the dismemberment and logical analysis of reality, which is mainly in charge of the left hemisphere, but by the perception of integral images, operating with complex associations. The right hemisphere is not inherent in verbal perception, but sensory-figurative. From this follow the syndromes that are formed when it is damaged. A very large part of the symptoms mentioned above is the result of damage to the right hemisphere. This, for example, is not recognizing faces - proso-pagnosia, a violation of the perception of the surrounding space, a violation of the ability to understand images in pictures, a violation of the ability to understand diagrams and plans, orientation on a geographical map.

Agnosia for nonverbal sounds has also been associated with right hemisphere damage.

The connection of the right hemisphere with visual-spatial thinking also causes the appearance of some complex mental phenomena in violations in the right hemisphere; so, for example, with a focus of pathological excitation in the right temporal lobe in epilepsy, visual illusions and states of “already seen” and “never seen” are observed.

There is reason to believe that this kind of visual mental activity, like dreams, is also associated with the right hemisphere of the brain. There are observations that when the right hemisphere is damaged, dreams can stop (In the overwhelming majority of dreams, according to the figurative definition of I. M. Sechenov, they are an incredible, fantastic realization of real, probable, experienced events) or they become meaningless in content, often associated with the topic diseases are frightening. A body schema disorder is also considered a sign of damage to the right hemisphere of the brain.

Violation of the body schema. The concept of violation of the body schema includes disorientation in one's own body, which is associated with a violation of the integration of sensitive perceptions and with a disorder in the understanding of spatial relationships. In such cases, it may seem to the patient that his head is unreasonably large, his lips are swollen, his nose is stretched forward, his arm is sharply reduced or enlarged and lies somewhere nearby, separately from the body. It is difficult for him to understand the "left" and "right". Violation of the body scheme is especially pronounced in a patient with a right-hemisphere lesion with the simultaneous presence of left-sided hemiplegia, hemianesthesia and hemianopsia. This is understandable, since the patient does not see or feel his paralyzed half of the body. He cannot find his hand, shows that it starts from the middle of the chest, notes the presence of a third hand, does not recognize his paralysis and is convinced of the possibility of getting up and walking, but "does not" because he "does not want to." If such a patient is shown his paralyzed hand, he does not recognize it as his own. This phenomenon anosognosia(from the Greek nosos - a disease, gnosis - knowledge, recognition, anosognosis - lack of consciousness of one's illness, usually paralysis of a limb or blindness) and phenomena autopagnosia(not recognizing parts of one's own body). In the presence of diffuse atherosclerotic lesions of the vessels of the brain, the patient sometimes expresses delusional thoughts, arguing, for example, that the hands of the dead are chopped off and thrown into his bed. (“These hands, cold, suffocate, digging into the skin and body with their nails”). The patient cries bitterly, asking to stop the ruthless treatment of him. To get rid of the annoying "foreign" hand, the patient can, grabbing his paralyzed hand with his healthy hand, beat the latter with all his strength against the bed or wall. There are no persuasions involved. Various kinds of paresthesias are painfully transformed into colorful and lush delirium.

Apraxia, or disorder of action, consists in a violation of the sequence of complex movements, i.e., in the disintegration of the desired set of movements, as a result of which the patient loses the ability to clearly perform habitual actions with full preservation of muscle strength and preservation of coordination of movements.

All our actions, representing an integrative function of different levels of the nervous system, are provided by different parts of the brain.

Arbitrary movements will be clearly performed if:

1) preserved afferentation, kinesthesia, which is associated with sections of the posterior central gyrus (test: the patient, without looking at his fingers, must copy the position of the doctor's fingers);

2) preserved visual-spatial orientation, which is associated with the parietal-occipital cortex (test: copy the combination of hand on hand, fist under fist, make a figure out of matches, right - left side);

3) the preservation of the kinetic basis of movements, which is mainly associated with the precentral region of the anterior central gyrus (test: copy a quick fist change with two fingers, knocking on the table with different rhythms and intervals);

4) the preservation of the programming of the action, its purposefulness, which is associated with the anterior sections of the frontal lobes (test: the fulfillment of target tasks, for example, beckon or threaten with a finger, follow this or that order). If one of the listed cortical regions is damaged, one or another type of apraxia will be observed:

2) spatial and constructive apraxia;

3) dynamic apraxia (apraxia of execution);

4)frontal apraxia, i.e., apraxia of intent, or, as it is also called, ideational apraxia (Fig. 101).

Of course, we must not forget that the clarity of our movements also depends on other parts of the nervous system, as mentioned above. After all, learned by man and entrenched in dynamic stereotype(into a motor image) complex voluntary movements arose and developed with a very effective participation of both afferent and efferent systems. As V. I. Lenin figuratively wrote, “... the practical activity of a person billions of times had to lead the consciousness of a person to repetitions of various logical figures, so that these figures could receive the value of axioms.” Breakdown in the activity of these systems leads to praxic disorders, most pronounced in cases of damage in the premotor or parietal cortex.

Establishing the nature of apraxia is of great importance in a monolocal process, such as a tumor. With vascular lesions, we often observe mixed forms of apraxia, for example, postures and constructive or constructive and dynamic. Along with the fuzziness of movements, the patient may experience, at first glance, the phenomena of ridiculous behavior. The patient, on assignment, cannot raise his hand, blow his nose, put on a dressing gown; when offered to light a match, he can take it out of the box and start striking on his dressing gown with the end not covered with gray; he may begin to write with a spoon, comb his hair through his cap;

the ability to construct a whole from parts, for example, a house of matches, pantomimically depict this or that action, for example, wag a finger, show how they sew on a sewing machine, hammer a nail into a wall, etc.

Often, with apraxia, perseveration is observed, that is, “sticking” to a once perfect action, slipping onto the beaten path. So, a patient who sticks out his tongue on demand, with each new task - to raise his hand, close his eyes, touch his ear, continues to stick out his tongue, but does not perform the new task.

The syndrome of constructive apraxia, which develops in patients with right hemisphere lesions, is associated with impaired visual-spatial perception. Clearly aware of the purpose of the task, the patient cannot properly organize the sequence and interconnection of acts in time and space and understand the structure of the task being performed. The characteristic combination of agnosia and apraxia made it possible to unite these disorders that occur when the right hemisphere is affected, under a single term - apractognostic syndrome.

The parietal lobe is separated from the frontal central sulcus, from the temporal - by the lateral sulcus, from the occipital - by an imaginary line drawn from the upper edge of the parietal-occipital sulcus to the lower edge of the cerebral hemisphere. On the outer surface of the parietal lobe, a vertical postcentral gyrus and two horizontal lobules are distinguished - the upper parietal and the lower parietal, separated by a vertical groove. The part of the lower parietal lobule located above the posterior part of the lateral sulcus is called the supramarginal (supramarginal) gyrus, and the part surrounding the ascending process of the superior temporal sulcus is called the angular (angular) gyrus.

In the parietal lobes and postcentral gyrus, the afferent pathways of skin and deep sensitivity end. Here, the analysis and synthesis of perceptions from the receptors of surface tissues and organs of movement are carried out. When these anatomical structures are damaged, sensitivity, spatial orientation and regulation of purposeful movements are disturbed.

Anesthesia (or hypesthesia) of pain, thermal, tactile sensitivity, disorders of the joint-muscular feeling appear with lesions of the postcentral gyri. Most of the postcentral gyrus is occupied by the projection of the face, head, hand and fingers.

Astereognosis is the inability to recognize objects by touching them with closed eyes. Patients describe individual properties of objects (for example, rough, with rounded corners, cold, etc.), but cannot synthesize an image of an object. This symptom occurs with lesions in the superior parietal lobule, near the postcentral gyrus. With the defeat of the latter, especially its middle part, all types of sensitivity for the upper limb fall out, so the patient is deprived of the opportunity not only to recognize the object, but also to describe its various properties (false astereognosis).

Apraxia (a disorder of complex actions with the preservation of elementary movements) occurs as a result of damage to the parietal lobe of the dominant hemisphere (in right-handed people - the left one) and is detected during the functioning of the limbs (usually the upper ones). Foci in the region of the supramarginal gyrus (gyrus supramarginalis) cause apraxia due to the loss of kinesthetic modes of action (kinesthetic or ideational apraxia), and lesions of the angular gyrus (gyrus angularis) are associated with the disintegration of the spatial orientation of actions (spatial or constructive apraxia).

A pathognomonic symptom in lesions of the parietal lobe is a violation of the body scheme. This is expressed by non-recognition or distorted perception of parts of their body (autopagnosia): patients confuse the right half of the body with the left, cannot correctly show the fingers of the hand when calling them a doctor. Less common is the so-called pseudopolymelia - a feeling of an extra limb or other part of the body. Another type of body schema disorder is anosognosia - not recognizing the manifestations of one's disease (the patient, for example, claims that he is moving his paralyzed left upper limb). Note that disorders of the body scheme are usually noted with lesions of the non-dominant hemisphere (right - in right-handers).

When the parietal lobe is affected in the area that borders on the occipital and temporal lobes (fields 37 and 39 are phylogenetically young formations), the symptoms of a violation of higher nervous activity are combined. So, turning off the posterior part of the left angular gyrus is accompanied by a triad of symptoms: digital agnosia (the patient cannot name the fingers), acalculia (counting disorder) and violation of the right-left orientation (Gerstmann's syndrome). These disorders may be accompanied by alexia and symptoms of amnestic aphasia.

Destruction of the deep parts of the parietal lobe leads to lower quadrant hemianopsia.

Symptoms of irritation of the postcentral gyrus and the parietal lobe are manifested by paroxysms of paresthesia - various skin sensations in the form of crawling, itching, burning, the passage of an electric current (sensory Jacksonian seizures). These sensations arise spontaneously. With foci in the postcentral gyrus, paresthesias usually occur in limited areas of the integument of the body (more often on the face, upper limb). Cutaneous paresthesias before epileptic seizures are called somatosensory auras. Irritation of the parietal lobe posterior to the postcentral gyrus causes paresthesia immediately on the entire opposite half of the body.

Syndromes of local lesions of the parietal lobes

I. Postcentral gyrus

1. Elementary somatosensory disorders
   • Contralateral decrease in sensitivity (stereognosis, musculoskeletal feeling, tactile, pain, temperature, vibration sensitivity)
   • Contralateral pain, paresthesia

II. Medial departments (cuneus)

1. Transcortical sensory aphasia (dominant hemisphere)

III. Lateral sections (upper and lower parietal lobules)

1. dominant hemisphere
   • Parietal apraxia
   • Finger agnosia
   • Acalculia
   • Right-left disorientation
   • Literal alexia
   • Alexia with agraphia
   • Conduction aphasia
2. non-dominant hemisphere
   • Anosognosia
   • Autopagnosia
   • Hemispace Neglect
   • Constructive Apraxia
   • Apraxia dressing

IV. Epileptic phenomena characteristic of the parietal localization of the epileptic focus.

Damage to the parietal lobe is accompanied by various variants of agnosia, apraxia and spatial disorientation.

In addition to what has been said in the literature, many other neurological syndromes associated with the parietal localization of a brain lesion have been repeatedly described. A rare syndrome is parietal ataxia. It develops when those parts of the parietal lobe are affected, into which proprioceptive, vestibular and visual sensory streams converge, and is manifested by decomposition of movements, hyper- and hypometry, and tremor.

Often, muscle atrophy (especially of the arm and shoulder girdle) is also described in the opposite half of the body, which sometimes precedes paresis in slowly ongoing pathological processes.

Parietal injuries in the first three years of life are sometimes accompanied by a lag in the growth of bones and muscles on the opposite half of the body.

Manual and oral apraxia, hypokinesia, echopraxia, paratonia (gegenhalten) are described.

Variants of the thalamic syndrome sometimes develop with parietal damage. With processes in the posterior parts of the parietal lobe, visual disorders may appear in the form of visual field defects. Unilateral visual neglect (neglect or inattention) can be observed without a visual field defect. Violations of visual perception (metamorphopsia) can occur with both bilateral and unilateral lesions (often on the right). There are separate indications of the possibility of the appearance of violations of eye tracking movements and optokinetic nystagmus, a mild decrease in intelligence, mental blindness, digital agnosia (in the picture of Gerstmann's syndrome), spatial orientation disorders (the posterior parts of the parietal lobe play a special role in visual-spatial directed attention, the ability to direct visual attention to a particular place in the surrounding space). The phenomenon of "beautiful indifference" in hemispace neglect syndrome, deterioration in the recognition of emotional vocalizations, and depression are also described.

I. Postcentral gyrus.

Lesions in this area are manifested by well-known somatotopically organized contralateral sensory disturbances (impaired stereognosis and muscle-articular feeling; tactile, pain, temperature, vibrational hypoesthesia) as well as contralateral paresthesias and pain.

II. Medial parts of the parietal lobe (precuneus)

The medial parts of the parietal lobe (precuneus) face the interhemispheric fissure. Lesions in this area in the left (speech-dominant) hemisphere may present with transcortical sensory aphasia.

III. Lateral sections (upper and lower parietal lobules).

Defeat dominant The (left) parietal lobe, especially the gyrus supramarginalis, presents with typical parietal apraxia that occurs in both hands. The patient loses the skills of habitual actions and in severe cases becomes completely helpless in handling this or that object.

Finger agnosia - the inability to recognize or name individual fingers, both in oneself and in another person - is most often caused by damage to the gyrus angularis or nearby zone of the left (dominant) hemisphere. Acalculia (inability to perform simple counting operations) has been described with damage to various parts of the cerebral hemispheres, including damage to the left parietal lobe. Sometimes the patient confuses the right side with the left (right-left disorientation). With the defeat of the angular gyrus (gyrus angularis), alexia is observed - the loss of the ability to recognize written characters; the patient loses the ability to understand what is written. At the same time, the ability to write is also impaired, that is, alexia with agraphia develops. Here the agraphia is not as rough as in the case of damage to the second frontal gyrus. Finally, damage to the parietal lobe of the left hemisphere can lead to symptoms of conduction aphasia.

Pathological processes in the parietal lobe non-dominant hemispheres (for example, a stroke) can be manifested by anosognosia, in which the patient is not aware of his defect, most often paralysis. A rarer form of agnosia is autotopoagnosia - a distorted perception or unrecognition of parts of one's own body. At the same time, symptoms of a distorted body scheme (“hemidepersonalization”), difficult orientation in parts of the body, a feeling of having false limbs (pseudomelia) are observed. Possible violation of spatial orientation. The patient, for example, begins to experience difficulty in any action that requires orientation in space: the patient is unable to describe the way from home to work, unable to navigate in a simple plan of the area or in terms of his own room. The most prominent symptom of damage to the inferior parietal lobule of the non-dominant (right) hemisphere is hemispatial contralateral neglect (neglect): a distinct tendency to ignore events and objects in one half of the space contralateral to the damaged hemisphere. The patient may not notice the doctor if the latter is standing by the bed on the side opposite to the hemispheric injury. The patient ignores the words on the left side of the page; trying to find the center of the horizontal line, he points to it, moving significantly to the right, and so on. Perhaps the appearance of constructive apraxia, when the patient loses the ability to perform even elementary actions that require clear spatial coordinates. Apraxia of dressing has been described with damage to the right parietal lobe.

A lesion in the inferior parietal lobule sometimes presents with a tendency not to use the arm contralateral to the injury, even if it is not paralyzed; she exhibits awkwardness in performing manual tasks.

Neurological syndromes of lesions of the parietal lobe can be summarized in another way:

Any (right or left) parietal lobe.

1. Contralateral hemihypesthesia, a violation of the sense of discrimination (with damage to the posterior central gyrus).
2. Hemispace Neglect.
3. Changes in the size and mobility of the contralateral limb, including muscle volume and growth retardation in children.
4. Pseudothalamic syndrome
5. Violation of tracking eye movements and optokinetic nystagmus (with damage to the parietal associative cortex and deep white matter).
6. Metamorphopsia.
7. Constructive Apraxia
8. Parietal ataxia (retrorolandic area).

Non-dominant (right) parietal lobe.

1. Constructive Apraxia
2. Spatial disorientation
3. Deterioration of speech recognition
4. affective disorders.
5. Unilateral spatial neglect.
6. Apraxia of dressing.
7. Attention disorders, state of confusion.
8. Anosognosia and autopagnosia

Dominant (left) parietal lobe.

1. Aphasia
2. Dyslexia
3. Agraphia.
4. Manual apraxia
5. constructive apraxia.

Both parietal lobes (simultaneous involvement of both parietal lobes).

1. visual agnosia.
2. Balint (strongalint) syndrome (develops with damage to the parietal-occipital region of both hemispheres) - a patient with normal visual acuity can perceive only one object at a time; apraxia).
3. Gross visual-spatial disorientation.
4. Rough constructive apraxia.
5. Autopagnosia.
6. Bilateral severe ideomotor apraxia.

IV. Epileptic paroxysmal phenomena characteristic of the parietal localization of the epileptic focus.

touch areas. primary sensory area.

1. Paresthesia, numbness, rarely - pain in the opposite half of the body (especially in the hand, forearm or face).
2. Jackson Sensory March
3. Bilateral paresthesias in the legs (paracentral lobule).
4. Taste aura (lower rolandic region, islet).
5. Paresthesia in the tongue (numbness, tension, coldness, tingling)
6. Abdominal aura.
7. Bilateral facial paresthesias
8. Genital paresthesias (paracentral lobule)