Agnosia from all senses. visual agnosia

agnosia (from Greek a - negative particle + gnosis - knowledge)- violation various kinds perception that occurs when the cerebral cortex and the nearest subcortical structures are damaged. A. is associated with damage to the secondary (projection-associative) sections of the cerebral cortex, which are part of the cortical level of the analyzer systems. The defeat of the primary (projection) sections of the cortex causes only elementary disorders of sensitivity (impairment of sensory visual functions, pain and tactile sensitivity, hearing loss). When the secondary parts of the cerebral cortex are damaged, a person retains elementary sensitivity, but he loses the ability to analyze and synthesize incoming information, which leads to a violation of the recognition processes in different modalities.

There are several main types of Agnosia: visual, tactile, auditory.

Spotting Agnosia occur with damage to the secondary sections of the occipital cortex. They manifest themselves in the fact that a person - with sufficient preservation of visual acuity - cannot recognize objects and their images (subject Agnosia), distinguish the spatial features of objects, the main spatial coordinates (spatial A.); the process of identifying faces is disturbed while the perception of objects and their images is preserved (A. on faces, or prosopagnosia), the ability to classify colors is impaired while color vision is preserved (color Agnosia), the ability to distinguish letters is lost (letter Agnosia) (this type of A. lies at the heart of one of the forms of impaired reading, see Alexia), the volume of simultaneously perceived objects is sharply reduced (simultaneous Agnosia). The nature of visual A. is determined by the side of the lesion and the localization of the focus within the secondary cortical fields of the occipital regions of the cerebral hemispheres and the parietal and temporal regions adjacent to them.

Tactile Agnosia arise when the secondary cortical fields of the parietal lobe of the left or right hemisphere are damaged and manifest themselves as a disorder in the recognition of objects by touch (astereognosia) or in a violation of the recognition of parts of one's body, a violation of the body scheme (somatognosia).

Auditory Agnosia occur with damage to the secondary cortical fields of the temporal lobe. With damage to the temporal cortex of the left hemisphere, auditory or auditory-speech A. manifests itself in the form of a violation of phonemic hearing, i.e. impaired ability to distinguish speech sounds, which leads to a speech disorder (see Aphasia); when the temporal cortex of the right hemisphere is damaged (in right-handed people), auditory A. itself occurs - the inability to recognize familiar non-musical sounds and noises (for example: barking dogs, creaking steps, the sound of rain, etc.) or amusia - the inability to recognize familiar melodies, disorder musical ear. (E.D. Khomskaya)

Psychological dictionary. A.V. Petrovsky M.G. Yaroshevsky

agnosia (from Greek a - negative particle and gnosis - knowledge)- a violation of various types of perception that occurs with certain brain lesions. Distinguish:

visual A., manifested in the fact that a person, while maintaining sufficient visual acuity, cannot recognize objects and their images;
tactile A., manifested in the form of disorders of recognition of objects by touch (astereognosia) or in violation of the recognition of parts of one's own body, in violation of the idea of \u200b\u200bthe body scheme (somatognosia);
auditory A., manifested in a violation of phonemic hearing, i.e. the ability to distinguish speech sounds, which leads to its disorder (see Aphasia), or in violations of the ability to recognize familiar melodies, sounds, noises (while maintaining elementary forms of hearing).

Dictionary of psychiatric terms. V.M. Bleikher, I.V. Crook

agnosia (and Greek gnosis - knowledge)- impaired recognition of objects and phenomena in a state of clear consciousness and the preservation of the functions of the organs of perception themselves. Sometimes the correct perception of individual elements of the object being identified is preserved. A. can be complete and partial. It is observed in organic lesions of the brain, capturing the cortical zones of the corresponding analyzers, the zones of their representation in the brain.

Agnosia ACOUSTIC- manifested by impaired recognition of sounds, phonemes and objects by their characteristic sounds. Complete A. acoustic is called spiritual deafness. Syn.: A. auditory.
Agnosia PAIN- characterized by impaired perception of pain stimuli.
Agnosia VISUAL(OPTICAL) - characterized by impaired recognition of visual images of objects and phenomena. The following forms are distinguished: 1) apperceptive, which is based on a violation of the visual synthesis of individual signs - the patient cannot distinguish the image and combine its elements into one meaningful whole; 2) associative, in which the patient clearly distinguishes the visual structure of the image, but cannot name the corresponding object. Complete A. visual is called spiritual blindness.
Agnosia ON FACE- loss of the ability to recognize familiar faces in direct communication and in photographs. Synonym: prosopagnosia, Bodamer's symptom.
Agnosia olfactory- characterized by a violation of the recognition of objects or substances by their typical smell.
Agnosia ONE-SIDE SPATIAL- violation of the perception of non-verbal stimuli (visual, tactile, auditory) emanating from the left half of the space. It is observed with damage to the posterior sections of the right hemisphere - the parietal-occipital sections of the cortex and subcortical formations [Korchazhinskaya V.I., Popova L.T., 1977]. Included in the structure of Zangwill and Geken apractagnostic syndromes.
Agnosia SPATIAL- a form of optical agnosia, characterized by a loss of the ability to navigate in space, in the location of objects and determine the distance between them. Seen in focal organic lesion brain of parietal-occipital localization. Synonym: geometric-optical agnosia, blindness of space.
Agnosia SIMULTANEOUS- characterized by a violation of the recognition of a group of objects as a whole in their totality or the situation as a whole, while individual objects are recognized correctly. It is observed with damage to the anterior part of the occipital lobe of the dominant hemisphere.
Agnosia AUDIOUS See A. acoustic.
Agnosia TACTILE- characterized by the inability to determine objects by touch, although their individual qualities (shape, mass, surface temperature) are qualified correctly. It differs from other types of astereognosis - anchilognosia (impaired recognition of the texture of an object, its mass, temperature) and amorphognostia (impaired recognition of the shape of an object). Syn.: tactile semantic agnosia.

Neurology. Full dictionary. Nikiforov A.S.

agnosia (a - negation of gnosis - knowledge)- a disorder of recognition with the preservation of sensitivity, perception and consciousness, arising in connection with a disorder in the functions of higher gnostic (cognitive) processes. In this case, the patient may have impaired recognition of objects when they are felt (tactile agnosia, astereognosis), which indicates damage to the cortex of the anterior parts of the parietal lobe on the left (in right-handed people) - field 40. Unrecognition of speech sounds (phonemes) and inability to recognize objects by characteristic them to sounds - auditory (acoustic) agnosia - usually occurs when the pathological focus is localized in the superior temporal gyrus. If the patient loses orientation in space and the ability to recognize objects he sees, then they talk about visual agnosia, which is observed when the function of the cortex of the left parieto-occipital region is impaired - cortical fields 18, 19, 33. With visual spatial agnosia, patients cannot navigate in terms of terrain , on a map, in a familiar area.

The term "agnosia" was introduced in 1881. German physiologist Munk (H. Munk, 1839–1912).

Agnosia acoustic- see Agnosia auditory.
depth agnosia- a variant of visual spatial agnosia (see). It manifests itself as a violation of the ability to correctly localize objects in three-dimensional space. Despite the fact that the patient sees and recognizes objects, he cannot correctly assess the distance to them and their relative position (it is difficult to assess the absolute and relative distance), it is difficult to determine the relative magnitude of several objects located at different distances from him. With significantly pronounced manifestations of depth agnosia, the patient may miss when trying to pick up a nearby object. He has difficulty walking: he often stumbles, dodges obstacles at the wrong time. According to most researchers, depth agnosia usually occurs when the parieto-occipital region is affected on the left. R. Brain (1965) noted that especially severe manifestations of violation of deep perception occur in bilateral lesions of the parieto-occipital regions of the cerebral hemispheres.
Agnosia visual- syn.: Optical agnosia. A disorder in the synthesis of visual sensations, difficulties in comparing them with information stored in memory. In this regard, the impossibility of recognizing and recognizing objects or their images with intact vision. A consequence of damage to the secondary visual cortex (fields, according to Brodmann, 18, 19), adjacent associative cortical zones of the lower parietal region (fields 39, 40) and temporo-occipital region (fields 37 and 21), as well as their connections with subcortical structures and limbic reticular system of the brain. Domestic neuropsychologist A.R. Luria (1973) interpreted visual agnosia as "the disintegration of the higher organization of the visual process." Agnosia visual object. Impossibility or difficulty in recognizing familiar objects and their images: realistic - with severe agnosia; if the degree of severity of agnosia is moderate - a disorder of recognition of abstract, incomplete, dotted, partial images of familiar objects. With object agnosia, the patient can usually characterize the individual properties of an unrecognized object: for example, examining a comb, he says that this object is narrow, flat, long, rough, sometimes he can name its color, but does not know what kind of object it is, and cannot determine its purpose. In 1898, the German neurologist H. Lissauer proposed to differentiate object visual agnosia into apperceptive, associative, and mixed.
Agnosia visual constructive- synonym: Poppelreiter-Volpert syndrome. Loss of the ability to synthesize fragments of an object and its image, to understand the meaning of a thematic drawing. Described by the German doctor Poppelreiter and the American doctor Wolpert.
Agnosia visual objective associative Lissauer- the patient perceives objects or their images with the help of vision, but is not able to correlate them with his previous experience, recognize and determine their purpose. It is especially difficult for the patient to recognize silhouette, stylized or contour drawings, especially in cases of "noise" of the latter and their imposition on each other (Poppelreiter's drawings, see). All these defects in visual perception are more clearly manifested if the examination is carried out under conditions of time deficit (0.25–0.5 sec), recorded using a tachistoscope. In cases And. n.a. there is a difficulty in extracting ideas, images of memories from the annals of memory. This form of agnosia usually occurs (in right-handers) with damage to the parieto-occipital region of the right hemisphere of the brain. N. Lissauer called it associative mental blindness.
visuo-spatial agnosia- the patient experiences difficulties of various degrees of severity and nature in compiling an idea of the spatial relationships between objects. Among various types visually spatial agnosia allocate depth agnosia (see), disorientation in space and unilateral spatial agnosia. Violations of orientation in space, or topographic orientation, lead to the fact that the patient loses the ability to navigate in the spatial coordinate system. He can get lost, leaving the hospital room into the corridor. It is difficult for him to understand the hands on the clock face. He is unable to orientate himself on a contour geographical map, he cannot repeat, on assignment, the changing position in the space of the hands of the doctor sitting opposite (Head's test). Patients with this form of pathology are not able to plan their apartment, room, hospital room. At the same time, violations of the right left orientation and signs of autotopagnosia are possible (see).
Agnosia for faces- synonym: Hoff-Petzl symptom. Prosopagnosia. Visual agnosia, manifested by the inability to recognize faces or portrait images (drawing, photograph, etc.) familiar or widely famous people(Pushkin, Tolstoy, Gagarin, etc.), a disorder of differentiation of male and female faces is possible. Sometimes the patient cannot even recognize his own face in a photograph or in a mirror. However, in the presence of prosopagnosia, he usually recognizes certain parts of the face - eyebrows, eyes, nose, mouth, bridge of the nose, chin, etc. Without differentiating faces, such a patient often recognizes familiar people by their gait, clothing, and voice. The cause of agnosia on faces is more often a lesion of the associative cortex of the right occipital-parietal region. He described this form of visual agnosia in 1932. G. Milian, he called it morphological blindness, and in 1937. H. Hoff and O. Petzl described this clinical phenomenon in more detail, designating it as a memory disorder for faces - prosopagnosia.
Agnosia for colors- Syn.: Achromatopsia. Violation of the ability to distinguish colors and differentiate them, select the same colors or shades of the same color, and also determine whether a particular color belongs to a particular object. At the same time, patients with impaired color perception sometimes retain elementary forms of color vision, which may enable them to recognize primary colors, but deprive them of the ability to differentiate their shades. In cases of complete color agnosia, there is an absolute absence of color perception. Agnosia for colors is often combined with object agnosia, in particular with agnosia for faces, and sometimes with visual alexia. He described color agnosia, highlighting it as a separate sign of cortical pathology, in 1908. M. Lewandowsky. Most authors (K. Kleist, 1932, Kok E.P., 1967) associate color agnosia (achromatopsia) with damage to the occipital region of the subdominant, therefore, more often the right hemisphere of the brain with a predominant lesion of the 19th cortical field, according to Brodmann, and adjacent association zones to it. Agnosia on colors in some cases is combined with agnosia on faces (see).
Agnosia olfactory and gustatory- loss of the ability to identify olfactory and gustatory sensations. It may be a consequence of dysfunction of the cortical end of the corresponding analyzers.
Optical agnosia- see Visual agnosia.
Agnosia digital- synonym: Gerstmann's syndrome. One of the forms of autotopagnosia (see). Violation of recognition and differentiated display of fingers, both one's own and fingers of other people. It is a sign of damage to the angular gyrus, more often the left hemisphere. Described by the Austrian neurologist J. Gerstmann (born in 1887).
Agnosia parietal- syn.: Petzl's syndrome is agnostic. One of the manifestations of visual agnosia (see) in patients with damage to the cortex of the posterior part of the angular gyrus of the left parietal lobe and adjacent parts of the occipital lobe. In this case, the patient, when reading and writing, does not recognize letters or is mistaken in differentiating letters similar in outline, which leads to a violation of reading and writing. Usually combined with a disorder of visual perception of numbers, musical signs, etc. Described in 1919. Austrian psychiatrist O. Potzl (1877–1962).
Anton's syndrome- a variant of anosognosia (see), in which a patient with severe visual impairment caused by damage to the cortex of the posterior parts of the cerebral hemispheres, sometimes stubbornly denies the existing visual defects. A patient with Anton's syndrome is usually verbose, prone to fiction, fantasy, and is uncritical about his condition. In such cases, the presence of a disorder in the connections of the occipital cortex with the structures of the diencephalon is assumed. It is more common in vascular pathology in elderly men. It was described in 1899 by the German psychoneurologist Anton (1858–1933). He called this rare clinical phenomenon cortical blindness.
Spatial agnosia, unilateral- ignoring part of the surrounding space, usually its left half, with a pathological focus in the parieto-occipital region of the subdominant and, therefore, more often the right hemisphere of the brain. The patient, as it were, loses sight of the left half of the space and his own body. He reads the text only on the right half of the page, sketches only the right side of the image, etc. When drawing objects from memory, a tendency is revealed to draw only the right half of it. The syndrome of unilateral spatial agnosia is rare.
Agnosia Simultana Volperta- the impossibility of covering the whole with the availability of perception of details. With it, it is possible to recognize individual objects, but it is impossible to perceive a group of objects as a whole, there is no ability to generalize what is visible. The patient usually recognizes most of the objects depicted in the thematic drawing, but cannot find a logical relationship between them. As a result, he is unable to understand the meaning of the plot picture. At the same time, verbal information, a story about the plot of the drawing, is perceived by patients correctly and with understanding. Simultaneous agnosia is sometimes combined with verbal alexia, in which individual letters are read correctly, but the patient cannot compose a word from them or at the same time has difficulty. The concept of simultaneous (from Latin simul - together, simultaneously) agnosia was formulated in 1924. I. Wolpert.
Auditory agnosia- syn.: Acoustic agnosia. Disorder of recognition of audible sounds that occurs when the superior temporal gyrus is damaged. At the same time, its defeat in the left hemisphere leads to the development of a violation of phonemic hearing characteristic of sensory aphasia. If the pathological focus is located in the right hemisphere of the brain, there is amusia (see) and disorders in the recognition of object sounds (the rustle of leaves, the murmur of a stream, etc.).
Agnosia tactile- see astereognosis.

Oxford Dictionary of Psychology

agnosia- literally "not knowing". Disruption of the recognition process. A person with agnosia can perceive objects and forms, but is not able to consciously recognize them and understand their purpose. Agnosia is the result of neurological pathology and can manifest itself in almost any perceptual/cognitive system. Exist various forms agnosia, some of which are described below, others in the corresponding articles, arranged alphabetically (for example, prosopagnosia).

subject area of the term

AGNOSIA visual subject associative Lissauer- The patient perceives objects or their images with the help of vision, but is not able to correlate them with his previous experience, recognize and determine their purpose. It is especially difficult for the patient to recognize silhouette, stylized or contour drawings, especially in cases of "noise" of the latter and their imposition on each other (Poppelreiter's drawings, see). All these defects in visual perception are more clearly manifested if the examination is carried out under conditions of time deficit (0.25–0.5 sec), recorded using a tachistoscope. In cases And. n. a, the difficulty of extracting representations, images-memories from the annals of memory is manifested. This form of agnosia usually occurs (in right-handers) with damage to the parieto-occipital region of the right hemisphere of the brain. N. Lissauer called it associative mental blindness.

COLOR AGNOSIA- the ability to classify colors is lost, to select the same colors or shades of the same color (especially brown, purple, orange, pastel colors). They are manifested by difficulties in differentiating mixed. In addition, one can note a violation of color recognition in a real object - difficulties in tasks to correlate one or another color with a specific object (say what color the grass, tomato, snow is). At the same time, elementary forms of color vision are not violated - patients can distinguish the primary colors presented on individual cards. Occurs mainly with damage to the left occipital lobe and adjacent areas. However, there is evidence of involvement in the process in this form of agnosia of the left parietotemporal region.

IDEATOR AGNOSIA- see agnosia, ideational.

APPERCEPTIVE AGNOSIA See agnosia, apperceptive.

Visual agnosia is a condition in which a person can see but is unable to recognize what they are seeing. The disturbance occurs in the visual centers of the brain, where in the normal state not only the image itself is formed, but also the associative memory of it. That is, the disease is characterized by the inability to recognize sensory signals of the visual analyzer from a familiar object. In another way, visual agnosia is also called object or mental blindness.

It should be understood that the patient's entire visual analyzer functions normally, there is no pathology in the refraction of light rays, their focusing on the retina, the formation of electrical impulses and their conduction to the brain. In comparison, one can contrast the blindness that atrophy gives optic nerve. With it, part or all of the neurons responsible for conducting a nerve impulse to the brain are lost. As a result, there is a violation of color and light perception, loss of areas of vision or complete blindness.

With visual agnosia, a person can copy a drawing, but cannot name what is shown

In optical agnosia, signals from the eyes travel to the visual centers in the brain but cannot be processed correctly. There is no synthesis of a single image from both eyes, or the association of pictures with an image or an abstract concept is broken.

Therefore, the treatment of agnosia is closer to the field of neuropsychology.

What causes visual agnosia?

It is believed that visual agnosia occurs when areas of the cerebral cortex in its parietal and occipital-parietal lobes are affected. It is here that the information responsible for associations with objects is analyzed and synthesized. The parietal cortex stores all the sensory information of the visual system, as well as tactile and spatial associations, sensory data from the skin about temperature, touch, and pain.

Visual images are formed in the brain, its damage causes optical agnosia

Lesions in these parts of the brain can be caused by:

Stroke. Damage to the brain occurs due to a violation of its blood supply as a result of ischemia, thrombosis, arterial embolism, or hemorrhage. Nervous tissue, not receiving oxygen, begins to die, and gradually parts of the brain lose their functions.
Neurological disorders and tumor processes. Visual agnosia occurs with a massive lesion of the occipital and parietal-occipital region of the brain.
Dementia. Neurodegenerative processes that occur in the brain with age lead to the loss of cognitive functions and memory. Most common cause dementia becomes Alzheimer's disease.

Other possible reasons:

hereditary predisposition;
meningeal infection;
mechanical damage to the occipital lobes in traumatic brain injury;
poisoning carbon monoxide;
recovery from prolonged blindness.

How to recognize

Most cases this disease seen in older people who have experienced some degree of brain damage. But signs of visual agnosia can occur at any age.

To understand how everything looks from the first person, imagine the following: you see two circles and a crossbar between them and you can’t even guess what it is and what it serves for. But healthy man when looking at this object, it is easy to determine that these are glasses. He immediately "knows" that they are put on the face and help improve vision.

Depending on the location of the occipital lobes, the damage to the brain occurred, the characteristics of visual agnosia differ.

With object agnosia, there is no holistic perception of the object, but its individual parts can be identified. A person enumerates the signs of an object, but cannot find out what it is.
Facial agnosia (prosopagnosia) occurs when damage occurs in the right hemisphere. A person cannot recognize people he knows by face or photo, and in a difficult case he cannot recognize himself.
Simultaneous agnosia does not allow the patient to look at all the objects that are in the field of view. Violation manifests itself in missing, disorientation. In this state, a person cannot draw anything within a given area (for example, in a circle) or circle a figure along a contour.
Visual-spatial agnosia. This type is also called one-sided, or left-sided, agnosia and is characterized by an "omission" from the view of the left half of the space and even one's body. The lesion is located on the right side of the brain, and the synthesis of images from two hemispheres into one does not occur. Manifested by the fact that a person "does not see" the left side of the text or picture, when asked to draw an object, he also draws from memory only its right side.
With agnosia for symbols (letters), the area of damage is determined on the border of the temporal and occipital lobes. The patient can copy letters and numbers, but cannot recognize and name them, and, accordingly, the reading skill is lost.
Color agnosia. It is characterized by the fact that, in principle, the patient can name the color if it is presented separately on the card, but when asked to name the color of a certain object (for example, strawberries), he experiences difficulty. Violation options: amnesia regarding the name of the shades, the inability to imagine the color (imagine it), cortical blindness ( complete absence color discrimination).
Agnosia of space with damage to the area in the upper occiput of the brain. Observed varying degrees disturbances in the perception of the coordinate system. The patient is not oriented in terms of left-right, up-down, cardinal directions, according to the distance of objects, but at the same time normal recognition of objects is maintained. Spatial agnosia is often combined with impaired coordination of movement, respectively, the ability to write and read suffers. There are also such types of visual agnosia regarding spatial perception: macropsia (objects seem larger) and micropsia (smaller than they really are), polymelia (perception of false limbs).

Diagnosis and treatment

It is quite difficult to make a diagnosis of visual agnosia, since the patients themselves do not even assume that they have a violation or compensate for it without medical intervention.

In most cases, optical agnosia is detected when preventive examination at the ophthalmologist. Confirmation of the diagnosis of agnosia begins with a search for any previous episodes of brain damage (trauma, stroke), carbon monoxide poisoning, the presence of the disease in relatives. Cognitive ability tests are also conducted to determine dementia or other neurological diseases.

During the examination, the emphasis is on the ability of a person to recognize objects, to determine the entire object by its part, to compare the size and position in space.

Correction of various types of visual agnosia requires special exercises for the brain.

With object agnosia - the restoration of a generalized image of an object through its detailed analysis, comparison with other objects, including drawn ones, automation of the perception of a verbal image. Treatment of this type of agnosia is the main way to overcome reading difficulties in primary optical dyslexia.

With facial agnosia - strengthening the association between the visual image of familiar people and the verbal, cultural, scientific and other associations associated with them. To do this, use photo albums, catchy melodies, smells, discussion of appearance and character.

With color agnosia, the attitude to color is trained. This can be achieved by using stereotypical images (a red strawberry), then comparing other objects with it, coloring the contours of given images, practicing picking up a palette of shades.

Brain training for orientation in space is carried out as follows:

by studying objects that rotate, zoom in or out; using maps, which determine the direction and train in the search for objects by verbal prompts;
working with watches - determining the position of the hands, their symmetry, setting them in a given order;
identifying similar positions of objects in different situations(for example, you need to select all the pictures where the object lies on the surface or stands on the right).

With simultaneous agnosia, first of all, direct orientation in space is trained, especially movements carried out under visual control. To develop these skills, use additional method supports, for example, feeling the objects with which the action is carried out.

In unilateral agnosia, the emphasis is on the fact that the object has two symmetrical areas. To attract attention, objects for therapy are usually sharply distinguished by the color of the right and left sides.

It should be understood that the course of the disease is lifelong, and treatment is aimed at improving the quality of life and increasing patient safety.

Agnosia: On the organic basis of agnosia. Disorder of perception in violation of the ability to recognize objects while preserving consciousness, self-consciousness, as well as the periphery and conductive parts of the analyzing. With the defeat of the GM.

Visual agnosia - for colors, fonts, object (do not visually differentiate) objects describes, but cannot name.

object agnosia- impaired recognition of various objects while maintaining the function of vision. At the same time, patients can describe their individual signs, but cannot say what kind of object is in front of them. Occurs when the convexital surface of the left occipital region is damaged;
prosopagnosia (face agnosia) - a violation of the recognition of familiar faces with a preserved subject gnosis. Patients well distinguish parts of the face and the face as an object as a whole, but cannot report on its individual affiliation. In the most severe cases, they cannot recognize themselves in the mirror. The disorder occurs when the lower-occipital region of the right hemisphere is affected;
agnosia for colors- the inability to select the same colors or shades, as well as to determine whether a particular color belongs to a particular object. Develops with damage to the occipital region of the left dominant hemisphere;
weakness of optical representations- a disorder associated with the inability to imagine any object and describe its characteristics - shape, color, texture, size, etc. Occurs as a result of a bilateral lesion of the occipital-parietal region;
simultaneous agnosia- a disorder associated with the functional narrowing of the visual field and its limitation to only one object. Patients can simultaneously perceive only one semantic unit, that is, the patient sees only one object, regardless of its size. Develops with damage to the anterior part of the dominant occipital lobe;
agnosia due to opto-motor disorders(Balint's syndrome) - a disorder associated with the inability to direct the gaze in the right direction with a general intact function of the movement of the eyeballs. This leads to difficulty in fixing the gaze on a given object; especially difficult is the simultaneous perception of more than one object in the field of view. It is difficult for the patient to read, as he hardly switches from word to word. It develops as a result of bilateral lesions of the occipital-parietal region.

Opto-spatial agnosias- disorder of definition of various parameters of space. In this category there are:

depth agnosia- violation of the ability to correctly localize objects in three coordinates of space, especially in depth, that is, in the sagittal (forward) in relation to the diseased direction, to determine the parameters further-closer. It develops as a result of damage to the parieto-occipital region, mainly its middle sections;
stereoscopic vision disorder- damage to the left hemisphere;
unilateral spatial agnosia- a disorder in which one of the halves of the space falls out, often the left. It develops with damage to the parietal lobe, the contralateral side of the prolapse;
disorientation- a violation in which the patient cannot navigate in familiar places, cannot find a house, wanders in his own apartment. In this case, the memory remains intact. Develops with damage to the parieto-occipital region

Impaired perception of time and movement- disorders associated with a violation of the perception of the speed of the passage of time and the movement of objects. It is rare and only a few cases of such disorders associated with damage to the occipital lobes have been described. A disturbance in the perception of moving objects is called akinetopsia.

Auditory agony - the patient does not perceive sounds with the ear opposite to the lesion, defects in auditory memory, auditory arrhythmia, impaired intonation of speech. Develop with damage to the temporal region.

simple auditory agnosia - the inability to identify certain sounds - knocking, gurgling, ringing of coins, rustling of paper, etc.
auditory speech agnosia- the inability to recognize speech, which the patient recognizes as a set of unfamiliar sounds.

With agnosia, the generalizing function of perception is impaired. The more schematically an object is presented, the more difficult it is to perceive and name it.

Pseudoagnosia- the perception of not only the structure, but also the form is disturbed, when diffuseness of thinking appears, meaningfulness and generalization are violated, it is noted in dementia.

Somatoagnosia - disorder of recognition of parts of one's own body, assessment of their localization relative to each other. Violation occurs when various parts of the right hemisphere are affected ( Brodmann fields 7). There are two main types:

Anosognosia - lack of awareness of the disease. Which include:

hemiplegia anosognosia- unawareness and denial of the existence of a one-sided paralysis or paresis;
anosognosia of blindness- unawareness and denial of existence blindness. At the same time, confabulatory visual images are perceived as real;
anosognosia aphasia a disorder in which patients aphasia do not notice their mistakes, even if their speech is completely unintelligible.

Autopagnosia - a disorder in which there is an ignorance of half of the body, but mainly a lack of recognition of its individual parts (for example, patients cannot distinguish and correctly show parts of their own body - parts of the face, fingers), a violation of the assessment of the position of individual parts of the body in space. This group includes:

hemicorpus autopagnosia(hemisomatognosia) - ignoring half of the body with partial preservation of its functions. So, with complete or incomplete preservation of movements in the arm and leg, the patient does not use them to carry out various actions. He "forgets" about them, ignores their existence, does not include them in his work. This neglect applies only to the left half of the body. For example, a patient washes only one right hand, puts on slippers only on the right foot. In severe cases, the patient has a feeling of absence of the left half of the body;

somatoparagnosia- perception of the affected part of the body as foreign. The patient feels that another person is lying next to him, who owns one of his legs in the bed (the left leg of the patient), or it is not his leg, but a stick or other object. In some cases, there is a feeling that the body is sawn into two halves, that the head, arm or leg is separated from the body. Often there may be sensations of an increase or decrease in the left side of the body (macro- or microsomatognosia). The feeling of change in the size of certain parts of the body is usually combined with a feeling of weight or unusual lightness. These sensations are painful for the patient and are hard for them to experience;

somatic allosthesia- a disorder associated with a sensation of an increase in the number of limbs (fixed or moving). Most often it concerns the left extremities, especially the left hand (pseudopolyemia). The first descriptions of pseudopolymelia belong to V. M. Bekhterev (1894) and P. A. Ostankov (1904). Bulbo-spinal localization of the pathological process was present in both cases. In 1904, V. M. Bekhterev first described a patient with a right hemispheric focus and a feeling of an extra left hand. In foreign literature, pseudopolymelia is more often called “multiple phantom” limbs (supernumerary phantom limbs), “extra limb” (spare limb) or “doubling of body parts” (reduplication of body parts). Most often it occurs in vascular lesions of the brain, less often - after a traumatic brain injury, with brain tumors, with multiple sclerosis. The sensation of an extra limb could be an aura in epileptic seizures. In the overwhelming majority of cases, it was about doubling the arm, much less often, doubling of the arm and leg or one leg at the same time was noted. Very rarely, patients felt more than three arms or legs: F. Sellal et al. described a patient with "six arms", P. Vuilleumier et al. - "with four legs." An analysis of the literature describing patients who developed pseudopolymelia with brain damage revealed two important points. Firstly, pseudopolymelia was most often observed with damage to the right hemisphere of the brain. Secondly, in all patients, the localization of lesions was deep. The most frequently affected were the deep parts of the parietal lobe, the thalamus, its connections with the parietal lobe, and the internal capsule. The symptomatology, against which the sensation of extra limbs developed, was similar: there were always gross motor disorders in combination with sensory ones, and the muscular-articular feeling necessarily suffered. To this were added, in various combinations, symptoms characteristic of lesions of the right hemisphere: anosognosia, ignorance of the left side of space, hemicorpus autopagnosia, etc. A manifestation of the sensation of imaginary limbs is the phantom of amputated limbs, when patients after amputation of the hand, forearm, foot with lower leg continue to feel their presence. Sometimes pain occurs in the phantom limbs (in a patient with a removed hip, hip sciatica may occur). The most stable phantom sensations occur in the distal parts of the limbs - hands and fingers, feet and toes. Often, phantom limbs feel reduced or enlarged in size. One of the main conditions for the development of a phantom is the suddenness of amputation (trauma, surgery). In the event of a long disease development, leading to the need for amputation, the phantom usually does not occur;

posture autopagnosia- a disorder in which the patient cannot determine the position of the parts of his body (his hand is raised or lowered, he lies or stands, etc.) Patients find it difficult to copy the position of the hand in relation to the face, cannot accurately copy the position doctor's index finger but in relation to the face. Similar difficulties are observed in the same patients when recognizing and copying different orientations of the positions of the hands in relation to each other, demonstrated by the doctor. In all these tasks, the elements of postural praxis are very closely related to the body schema and its recognition. Postural autopagnosia is more common than digital agnosia. Occurs when the upper parietal region of the left hemisphere and its connections with the visual tubercle are damaged (bilateral disorders);

disorientation in right-left- the patient does not know which of his two arms or legs is right and which is left, cannot show the right eye or left ear. Difficulties increase if the patient must determine the right and left sides, show the right or left hand(eye) on the body of the doctor sitting opposite. This task becomes especially difficult if the doctor crosses his arms over his chest. Orientation disorders in the right-left arise when the left parietal lobe is damaged in right-handers (angular gyrus). However, relatively rare cases are described when such defects also occur with right parietal lesions (according to observations after neurosurgical operations);

digital agnosia(Gershtman's syndrome) - the patient cannot point the finger on his hand that the doctor shows on his hand, especially if the doctor changes the position of the hand. Most often, recognition errors are noted for the II, III and IV fingers of both the right and left hands. Signs of somatoagnosia for other parts of the body are usually not observed. Occurs with damage to the left parietal lobe (angular gyrus).

The disease takes its name from the Latin word gnosis, meaning "knowledge", the prefix "a" in medical terminology traditionally indicates the absence of any sign or function.

Causes of agnosia

As a rule, agnosia is the result of extensive damage to the parts of the cerebral cortex that are part of the cortical level of the analyzer systems. At the same time, in left-handers, agnosia occurs as a result of pathological changes the right hemisphere, for right-handers - the left, that is, the departments responsible for artistic or figurative perception.

The most common pathologies that cause agnosia are considered to be various disorders cerebral circulation, including post-traumatic or post-operative, as well as Alzheimer's disease and encephalopathy, regardless of its type.

Types and symptoms of agnosia

Modern medicine distinguishes three main types of agnosia: visual, tactile and auditory.

Visual agnosia is characterized by the inability of the patient to identify and name a particular object or several objects. At the same time, there is no decrease in visual acuity. This type of agnosia can take various forms, such as the inability to determine spatial coordinates (spatial agnosia), impaired ability to classify colors with full color perception (color agnosia), loss of reading skills and letter recognition (letter agnosia), a sharp reduction in the volume of simultaneously perceived objects (simultaneous agnosia) and so on.

The cause of visual agnosia is damage to the occipital regions of the cerebral cortex.

Tactile agnosia occurs as a result of damage to the cortical fields of the parietal lobe of one or both hemispheres of the brain and manifests itself in a violation of the ability to recognize objects by touch or, alternatively, in the inability to recognize parts of one's own body.

Auditory agnosia is expressed in the patient's inability to recognize speech sounds, that is, in violation of the phonemic function of hearing, familiar musical melodies, extraneous noises and sounds, such as a barking dog or the sound of rain, with complete preservation of hearing acuity. In the first case, auditory agnosia, as a rule, leads to a disorder speech development. This type of agnosia, most often, is the result of damage to the cortical fields of the temporal lobe of the brain.

Much less frequently than the first three types, there are gustatory and olfactory agnosias, in which the patient loses the ability to recognize food and objects by taste and smell, respectively. Taste buds and sense of smell at the same time retain their functions in full.

In some cases, pain agnosia is noted, expressed in the absence of a reaction to pain. This type of agnosia, most often, is the result of congenital lesions of the brain. Most doctors consider pain agnosia one of the varieties of tactile.

Treatment of agnosia

The treatment of agnosia is to eliminate its cause, that is, the disease that caused damage to the cerebral cortex and its subcortical structures. Doctors do not name any specific methods of treatment - in each case, the method of medical treatment is determined individually, depending on the severity of the disease, its course and possible complications. To compensate for the lost function, that is, to correct agnosia proper, the participation of a neuropsychologist, as well as other specialists, is required. If speech disorders occur, the participation of a speech therapist is necessary. In some cases, occupational therapy is used.

The recovery period usually takes about three months, but in the presence of complicated disorders it can be up to one year. If necessary, the treatment can be repeated. Relapses of agnosia after elimination of its cause, as a rule, do not occur.

The health of the brain entails the health of the whole organism. When a person begins to perceive the world around him in a distorted way, many begin to treat this phenomenon in two ways. Someone understands that a person is sick, he needs treatment. The rest refer to phenomena visible only to man, as miracles that need to be believed. Agnosia can become serious illness. Types, causes, symptoms and methods of treatment of this disease will be discussed in this article.

agnosia

It is necessary to define the concept of what agnosia is. This is a disease of sensory perception of the surrounding world, in which a person remains conscious. Often this disease manifests itself in violations of the functions of the brain. Violation of the projection (primary) departments leads to a distortion of sensory perception - vision, hearing or pain threshold. With damage to the secondary departments, the ability to receive and interpret external information is lost.

Agnosia is understood as a disturbed perception of the surrounding world, while the sense organs themselves are working properly. In other words, it can be called hallucinations, delusions, insanity. The sense organs work properly. The problem lies in the brain, which does not perceive or distorts information, giving the wrong answer. A person sees, hears or feels something that does not exist.

Sometimes agnosia is a symptom of another disease, and does not act as an independent disease. For example, poisoning or circulatory disorders in the brain leads to similar syndromes.

Often a similar condition is observed with toxic effects. For example, after the use of drugs, alcohol or poisoning with poisons, toxins. Parts of the brain begin to change their work, because of which a person sees something that is not there.

It should be noted that information in a distorted form can come both from the outside and from the body. Sensations of worms crawling under the skin or being foreign bodies inside the body are one of the signs of agnosia, when a person seems to be something that is not really there.

The patient himself can be quite healthy, especially the organs of his perception. Here it is necessary to find out the reasons why the brain incorrectly perceives or interprets information. It also excludes the possibility of brain damage.

Types of agnosia

The brain is responsible for the perception of information by various organs, respectively, here we can distinguish many types of agnosia:

Visual (optical). Manifested in the lack of recognition of familiar objects, as well as their properties. However, the person is not blind. It often develops against the background of other diseases, such as Alzheimer's disease. Its types:

Subject-visual. When it seems to a person that his vision has deteriorated, and he is also not able to recognize the object he is looking at.
Spatial-visual (topographic). A person cannot navigate in space, gets lost, does not recognize familiar places, and also cannot recognize the relationship of objects to each other.
Metamorphopsia. A person perceives objects in a distorted form. Macropsia is seeing things magnified. Micropsia is the vision of objects in a reduced form.
Prosopagnosia (facial agnosia). It seems to a person that he cannot recognize familiar people due to the fact that he has poor eyesight. In fact, his eyesight is good, but the brain does not recognize familiar faces.
Simultaneous (simultaneous). The inability to fully or holistically perceive the complex of sensory images and the lack of recognition of the image by its parts.
Agnosia for colors. A person is not able to recognize the color of those objects that he looks at. At the same time, he remembers what colors certain objects have, if you ask him from memory.
Neglect (ignoring half of the space). A person does not see the part of the space that opens before him.

auditory agnosia. It manifests itself in the fact that a person cannot recognize familiar sounds, while his hearing is excellent. There are such types:

Verbal. When a person does not understand familiar words.
Amusia. A person does not recognize familiar melodies and tones of voice.
Letter. The person does not recognize letters. Dysgraphia (writing disorder) and dyslexia (verbal blindness) are also traced here.

Tactile agnosia (astereognosis). A person is not able to recognize objects that are placed in his hands. He can describe the properties of an object, but he is not able to combine them into a whole and recognize which object is in his hands. The symptom is divided into primary and secondary. At primary symptom tactile sensitivity and musculo-articular perception are not impaired, in contrast to the secondary symptom.
Olfactory agnosia. A person does not recognize or perceive familiar smells.
Taste agnosia. It manifests itself in the fact that a person does not recognize tastes familiar to him. It often develops along with olfactory agnosia, since the parts of the brain of these centers are located nearby.
Pain agnosia. It manifests itself in the absence of the correct perception of pain stimuli. It occurs in the form of dysesthesia - non-perception of an injection as a touch.

In addition to external stimuli that the brain perceives through the senses, there are internal factors. What types of agnosia are considered here?

Anosognosia. A person does not perceive the defects of his body, there is no critical assessment. This is a condition in which a person denies that they have an illness, such as impaired vision or hearing loss. Here, Anton's syndrome is considered, in which a person has impaired vision, and the patient refutes this disease.
Anosodiaphoria. It is expressed in the indifferent attitude of a person to his defect (disease). The person is aware that he is ill, but has no feelings about it.
Autotopoagnosia. A person misunderstands his own body. It may seem to him that he has 2 heads or 4 legs. Refers to somatognosia (impaired perception of one's body). Here are the types:

Finger. It is observed with a distorted perception of the number or location of fingers, both in oneself and in others. A person cannot understand how many fingers he has, or does not distinguish left from right.
Polymelia. A person may appear to have many legs or arms.

visual agnosia

The most common type of distorted perception of the world is visual agnosia. This is a person's inability to perceive familiar objects, navigate in space, see layered contours, etc. If you ask the patient to draw an object, he will not be able to do this, because he does not recognize the phenomena as a whole. He can see individual details, contours, strokes, but the whole picture will not emerge.

The cause of this type of agnosia is the defeat of the occipito-parietal region. There are types of agnosia that have already been identified above: agnosia for faces, spatial agnosia, associative and apperceptive agnosia.

Lisauer's apperceptive agnosia is manifested in the fact that a person is not able to recognize complex objects. For example, he will be able to recognize the ball, but more complex objects with many details will already become unrecognizable. The patient is able to recognize contours, shapes, colors, etc.
Balint's syndrome manifests itself in "mental gaze paralysis." A person is not able to recognize several objects that stop his gaze. He also fails to turn his gaze to the object that is on the periphery.
Associative agnosia manifests itself in the inability to recognize objects because they are not clearly visible to a person.

With all types of visual agnosia, a person has excellent vision. The problem lies in the brain, which distorts the information that enters it.

Since people are rarely aware of their own illness, they can fantasize. Their eyes see, the brain distorts, and then the fantasy turns on. What is incomprehensible to a person can become something else. This attracts impressionable people who believe in miracles. Here, hallucinations and delusions can be observed if visual agnosia appeared against the background of an already existing mental illness.

Causes of agnosia

What could be the reasons that a person perceives the world around him distortedly, and his sense organs are completely healthy? Since the brain is responsible for the perception and processing of information, the causes of agnosia lie in the damage or disruption of its departments.

Note mainly the defeat of the parietal or occipital lobe of the brain. This may happen due to:

Circulatory disorders in the brain (stroke).
Tumors in the brain.
Chronic violation in the brain of blood circulation with the development of dementia.
Consequences of craniocerebral injuries, blows, injuries.
Inflammation of the brain (encephalitis disease).
Alzheimer's disease, in which amyloid protein does not break down in the brain, but accumulates.
Parkinson's disease, in which tremors, muscle stiffness, neuropsychological disorders develop.
Failed brain surgery.
Heart attack.
Degeneration of brain tissue.

In right-handers, the disease develops against the background of damage to the left hemisphere, and left-handers - the right one.

Any damage or dysfunction of the brain leads to the fact that a person perceives the incoming information in a distorted way. Such disorders can be observed not only as a result of active influence on the brain, but also after a long unconscious state.

Do not forget about the effects on the brain of various substances, such as drugs or alcohol. Here, both with the organs of perception and with the functions of the brain, everything is normal. However, the influence of certain substances distorts the perception of the world for some time. On the one hand, this may seem funny to some lovers of "unusual and spicy." On the other hand, constant exposure to harmful substances on the brain can lead to disorders.

Symptoms of agnosia

Agnosia can be diagnosed by observing the patient, as well as by holding instrumental research which confirm the dysfunction of the brain. The symptoms of agnosia that cannot be hidden by patients become vivid here:

Disorientation in space. A person is not able to recognize many objects in space, their ratio. It also cannot perceive itself in space.
Disease denial. A person does not perceive the fact that he is sick.
Indifference to the presence of the disease.
Violations in the recognition of objects by touch. Some details may not be perceived, as well as the subject as a whole.
Impaired sound recognition.
Distorted perception of his body, inability to tell how many legs he has, how long his fingers are, etc.
Not recognizing familiar people.
Inability to perceive different objects as a whole. He can see objects, but is unable to tell in what relation they are (for example, a glass on a table: he sees both the glass and the table, but is not aware that the glass is on the table).
Ignoring half of the visible space.

Thus, the symptoms depend entirely on the type of agnosia. At the same time, it may seem to the patient that everything is fine with him, only hearing or vision has fallen. He will blame the decrease in the acuteness of the perception of the organs, and not the disturbances in the perception of the brain.

The patient is not able to recognize his disease himself, not only because of the incorrect interpretation of what is happening, but also because of the inability to understand what is real and unreal. Only an answer from the outside world can make you think that something is going wrong. Relatives may notice that a person incorrectly recognizes or sees something. In the early stages, symptoms can be stopped or eliminated. If the disease has moved to the second stage, then we can talk about the impossibility of eliminating agnosia.

Treatment of agnosia

To date, there is no effective treatment agnosia. We are talking about damage or damage to the brain, so the main methods and manipulations are aimed at restoring these departments:

Prescribed drugs that improve blood circulation in the brain. Blood pressure is controlled.
Held surgical operations to eliminate tumors, ruptures, etc. from the brain. Without surgical intervention, tablets in this case will not help.
Medications that help in restoring neuropsychological functions.

The patient is constantly consulted by a neuropsychologist.

Many doctors perceive this disease as normal. The patient simply needs to be retrained in those skills that have been lost. If a person suffers from visual agnosia, then he is again taught shapes and colors, the relationship of objects in space, etc. If auditory agnosia has developed, then the person is taught sounds.

These are injuries that are difficult to repair. modern medicine. However, in some cases, such manipulations are effective and help patients to adapt to life. An exception is somatognosia, which requires constant monitoring by a doctor.

If agnosia was the result of a mental illness, then treatment is aimed at eliminating this disease. Since brain diseases are not always completely cured, the restoration of its departments also becomes incomplete.

If agnosia was the result of the abuse of toxic substances, then it is recommended to protect the patient from alcohol, poison, drugs and other substances. The body is cleansed of these substances, as well as taking drugs that improve the functioning of the brain.

Lifespan

Is it possible to talk about the fact that agnosia will somehow affect the life expectancy of a person? In fact, the disease itself does not kill, but the cause of death may be the cause that caused agnosia. If the brain is affected by some kind of infection or blood circulation in it is not restored, then an unfavorable prognosis is possible.

The site of mental health care site notes the shortest cure time for the disease at 3 months. Depending on the age, severity and type of the disease itself, the cure can take up to a year or more. The nature of the lesion and the possibility of restoring brain functions become important. In some cases, a person cannot be cured completely. With somatoagnosia, full recovery cannot be discussed at all.

If a person is not treated, then the outcome can be disappointing. In such cases, the person becomes completely anti-social. He cannot communicate effectively with people and do any work.

Preventive measures are not determined here due to the suddenness of the onset of the disease. However, doctors recommend:

Monitor blood pressure.
Heal from any disease of the body.
(alcohol, drugs, etc.).
Lead an active and healthy lifestyle.
Eat well.
Seek medical attention if you experience strange symptoms similar to agnosia.

The disease can take a person out of social life for a long time. It becomes an obstacle to successful contact with other people. Medicine continues to study this topic in order to help people with their disease. However, only preventive measures today can help in the prevention of agnosia.