Agnosia

Agnosia is the disease which is characterized by disturbance of some types of perception, resulted from damage of a cerebral cortex and nearby subcrustal structures.

At disturbance of projective (primary) departments of bark there are disorders of sensitivity (decrease in hearing, disturbance of visual and painful functions). In case secondary departments of bark of hemispheres are surprised, ability to perception and processing of the acquired information is lost.

Acoustical agnosia

Acoustical agnosia results from defeat of the acoustic analyzer. If a temporal part of the left hemisphere was damaged, then there is a disturbance of phonemic hearing which is characterized by loss of ability to distinguish speech sounds that can lead to frustration of the speech in the form of touch aphasia. At the same time the expressional speech of the patient represents so-called "verbal salad". Also there can be a disturbance of the letter from dictation and readings aloud.

At damage of the right hemisphere of the patient ceases to distinguish all sounds and noise. If front departments of a brain are surprised, then all processes proceed with safety acoustical and visual systems, but with disturbance of the general perception and a concept of a situation. Most often this type of acoustical agnosia is observed at diseases of mental character.

Arrhythmia of acoustical agnosia is characterized by inability to understanding and reproduction of a certain rhythm. Pathology is shown at damage of the right temple.

It is possible to allocate with a separate type of acoustical agnosia process which is shown by disturbance of understanding of intonation of the speech of other people. Occurs also at right temporal defeat.

Visual agnosia

Visual agnosia is a disturbance of ability to an identification of objects and their image at full safety of sight. Arises at numerous defeats of occipital department of a cerebral cortex. Visual agnosia is subdivided into several subspecies:

• Simultaneous agnosia is a disturbance of ability to perception of group of images which form a whole. At the same time the patient can distinguish the single and finished images. Develops as a result of defeat of area where there is a joint an occipital, parietal and temporal lobe of a brain;
• Color agnosia is an inability to distinguish colors at the kept color sight;
• Alphabetic agnosia - impossibility to learn letters. This pathology is called "the acquired illiteracy". At safety of the speech, patients cannot neither write, nor read. Develops at damage of a dominant hemisphere of occipital department.

Tactile agnosia

Tactile agnosia is a disturbance of recognition of forms and objects to the touch. Appears after defeat of a parietal lobe of the right or left hemispheres. There are several types of agnosia of similar character:

• Subject agnosia – pathology at which the patient cannot determine the size, a form and material of this or that subject at the same time it is capable to define all its signs;
• Tactile agnosia - inability to an identification of the letters and figures drawn on the patient's hand;
• Manual agnosia - the pathology which is characterized by disturbance of definition of names of fingers of hands during a touch to them at the closed patient's eyes;
• Somatoagnoziya - inability to identify parts of a body and their arrangement on the relation to each other.

Space agnosia

Such look as space agnosia, is characterized by impossibility to learn space images and to be guided on site. In such situations of the patient cannot distinguish right from left, confuses an arrangement of arrows on hours and in words interchanges the position of letters. It is shown as a result of defeat of a temneno-occipital share. Diffusion disturbances of cortical structures can lead to a syndrome at which the patient ignores a half of space. At this option of space agnosia he does not notice the objects or images located on the one hand at all (for example, from right). During a pererisovyvaniye it represents only a part of the drawing, saying that other part does not exist in general.

Anosognosia

Among all other forms of this pathology, allocate a special type of agnosia - a so-called anosognosia (Anton-Babinsky's syndrome). This pathology is characterized by denial sick his diseases or reduced criticality of its assessment. Occurs at defeats of a subdominant hemisphere.

Diagnosis, treatment and the forecast at agnosia

Diagnosis of agnosia happens in the course of comprehensive neurologic examination, its exact look comes to light by means of special tests.

Treatment of this symptom complex is done during treatment of a basic disease and therefore differs in considerable variability. As well as treatment, the forecast depends on weight of the main pathology. In medical practice cases, both spontaneous treatment of agnosia, and long disease, almost lifelong are described.