Agnosia is a disorder characterized by a malfunctioning of certain types of perception. Pathology affects people of any age. A person as a result of agnosia can lose hearing, ceases to recognize objects, faces, or sees them distorted. Intellect with weakly expressed forms of agnosia is preserved.
Agnosia - what is it?
The person is guided in the world around by means of sensory systems of the central nervous system. The ability to capture, recognize, reproduce and understand symbolic meanings is gnosis (other Greek γνῶσις - knowledge). Agnosia is the loss or violation of perceptual functions as a result of lesions of a portion of the cortex and nearby subcortical areas. The term "agnosia" was introduced into the medical scientific environment by the German physiologist German Munch, who proved that the lesions of certain areas of the cortex can lead to blindness and deafness.
Agnosia in Psychology
Agnosia is a more organic disturbance, leading to changes in perception . Psychologists examine agnosia in terms of human adaptation against the background of pathological changes. In psychosomatics there are beliefs that vision problems arise in those people who are afraid to face their problems face to face, or do not want to see the obvious things, or there is an aversion to this world. Through the organs of hearing, a person receives information about the world, criticism, praise. People who are afraid of conflict and criticism may have problems with auditory analyzers.
Causes of agnosia
The main causes of agnosias are lesions or pathologies of the brain. Also common reasons are:
- progressive benign and malignant neoplasms of the brain;
- myocardial infarction;
- craniocerebral trauma of open and closed type with bruises, accidents;
- congenital pathology of the central nervous system;
- Parkinson's disease ;
- pathological heavy births;
- mental illness (senile dementia);
- degenerative changes in the brain;
- severe infectious diseases affecting the central nervous system (meningitis, encephalitis);
- disorder of cerebral circulation;
- exposure to toxic substances on the brain (mercury, lead, arsenic, psychoactive substances);
- Alzheimer's disease.
Types of agnosia
Agnosia is a disease that is rare, but it shows itself in a variety of forms. It appears more often between the ages of 10 and 20 years. There are 3 types of agnosia:
- visual;
- auditory;
- tactile.
Intermediate forms of agnosios:
- auditory;
- apperceptive;
- spatial;
- color;
- associative;
- anosognosia (Anton-Babinsky syndrome);
- painful;
- olfactory.
Auditory agnosia
Acoustic agnosia belongs to a sensitive species. There is a violation of recognition of sounds, speech in general. Damage to the temporal lobe of the left hemisphere leads to a disorder of phonemic hearing and manifests itself as follows:
- speech disorder (sensory aphasia);
- loss of ability to distinguish between speech sounds;
- speech of the patient is a "verbal salad";
- violation of reading and writing.
If the temporal lobe of the right hemisphere is affected:
- Noises and sounds are not recognized at all;
- Violation of understanding of intonation in the speech of other people;
- impossibility to learn and reproduce musical melodies;
- violation of recognition of loved ones by voice.
Tactile agnosia
Tactile agnosia is the inability to distinguish the qualitative characteristics inherent in objects. Recognition of texture: softness-hardness, smoothness-roughness becomes impossible, while the sensory basis of tactile perception is preserved. Tactile agnosia occurs when certain areas of the cortex of the upper and lower parietal regions are affected. Asteroignosis is a kind of disorder in which the patient does not recognize familiar objects to the touch with closed eyes.
Somatoignosia
Somatoignosia is a violation of the perception of the scheme of one's own body, inner space. In some classifications, somatoagnosis is referred to as tactile agnosia. There are three main forms of somatoagnosis:
- Anosognosia (Anton-Babinsky syndrome, a phenomenon of cortical blindness). Such a violation in the perception of the patient, when he denies the presence of his violations: paralysis, blindness, deafness. The patient believes that he is not paralyzed, but simply does not want to move. The cause of anosognosia is a lesion of the parietal lobe of the subdominant cerebral hemisphere in vascular disorders (more often in elderly men).
- Autopagnosia . The patient loses the knowledge of the localization of various parts of his body. Sometimes the patient can feel the presence of his "extra" limbs (third arm, leg, bifurcation) or lack of body parts (more often on the left side). The causes of autopagnosia can be traumas, tumors, stroke of severe form. Autopagnosia is a concomitant diagnostic symptom for mental illness: epilepsy, schizophrenia.
- Fingearognosia . This form is characterized by the inability to distinguish between the fingers of the hand with open and closed eyes not only in themselves, but also with an outsider.
Spatial agnosia
The concept of agnosia spatial includes an optical component. This type of agnosia is marked by symptoms of a disorder of perception of space, its parameters, disorientation in space. Spatial agnosia is subdivided according to the types of disturbances:
- > One-sided spatial agnosia. The reason is the defeat of the parietal lobe, mostly the right one. The sick person starts to see only the right side of the space (reads the text only on the right side of the field) the left one is ignored.
- Disturbances in perception of movement and time (akinetopsia). Speed, movement of objects are not perceived. A person can not read the diagram and maps, does not determine the time by moving arrows on the clock.
- Topographic agnosia - unrecognized familiar routes, complete disorientation in space, memory is preserved. Patients may get lost at home in their room.
- A gnosis of depth - develops in the lesions of the parieto-occipital region (middle section). It manifests itself in the impossibility for patients to localize correctly objects in three-dimensional space. A person with depth agnosis does not distinguish parameters closer, further, forward-backward.
Visible agnosia
The most numerous group of agnosias, caused by the defeat of the occipital parts of the cortex and visual analyzers, become incapable of perceiving and processing the information received from outside about objects and phenomena. In medicine, the following forms of agnosia are known:
- subject (the recognition of objects is broken, but vision is preserved);
- digital (the patient can not name the numbers);
- agnosia for dementia (pseudo-ignoses - unrecognized silhouettes of objects and dotted drawings: a fungus, if on top - a tomato, if from below - a cucumber).
Frequently occurring forms of visual agnosia, which can be considered in more detail:
- prosopagnosia;
- Simultaneous;
- alphabetic;
Literal agnosia
The second name for the disease is asymmetry. Alpha agnosia occurs when the left parietal and occipital lobes are affected. In this violation, the person correctly copies, copies the proposed samples of letters, numbers, but can not name them, does not recognize and does not remember. Letter agnosia entails the development of primary alexia (inability to read the text) and acalculia (account violation). Characteristic manifestations:
- mirror perception of letters;
- letters are mixed according to optical proximity and a similar arrangement of elements in letters ("n" as "m", "p" as "in").
Simultaneous agnosia
Balint's syndrome or simultaneous agnosia is a violation of the holistic perception of the image, pictures, a series of images. Individual objects and objects are perceived correctly. The cause of agnosia in the lesion of the anterior part of the occipital lobe. It appears as follows:
- difficult and slow reading;
- complexity in redirecting the view to the other side (unmanageable view);
- violations in the movement of eyeballs;
- the ability to perceive only one object in the image.
Prozapognosia
This kind of visual agnosia is of interest to specialists. Prosopagnosia or agnosia on the face is formed when the right lower occipital lobe or right temporal region is affected. There is an innate form of pro-spontgenia that is transmitted genetically (more often it is a mild disorder in 2% of the population). Accompanies Alzheimer's disease. Characteristic manifestations:
- the perception of the person is not violated, but the patient does not identify him with a specific person, he does not recognize;
- the ability to recognize a familiar person by individual elements of the face: a mustache, teeth, eyes, nose.
The case of prozopagnosia is described in the book of the neuropathologist "A man who took his wife for a hat". Patient P., suffering from agnosia, could recognize his wife only by voice. In an easy degree, prosopagnosia was recorded in A.S. Pushkin, N.V. Gogol, Yu. Gagarin, L.I. Brezhnev. In the fact that he has a diagnosis of prosopagnosia - Brad Pitt, a famous American actor recently told the media. Brad is very upset that his friends and acquaintances take offense at him, when he often passes by and does not stop to say hello.
Correction of agnosios
Agnosia is rarely independent, often accompanied by serious diseases or brain damage. A thorough examination and thorough diagnosis can help to discover the causes of a particular type of agnosia, only after that individual symptomatic medication therapy is selected. Correction of agnosias of various etiologies is carried out by specialists: neuropathologist, psychiatrist, defectologist, psychotherapist. A successful prognosis depends on the timely diagnosis and the measures taken:
- possible complete recovery, with the cure of the underlying disease;
- long-term remission, supported by preventive doses of drugs;
- adaptation of a person with life-expecting agnosia: various activities aimed at socialization and assimilation of lost skills in a partial form through the development of new neural connections.