Agnosia - Causes and Symptoms

Agnosia disorders in recognizing or interpreting sensory impressions
In the presence of agnosia, a very rare disease, disorders occur in recognizing or interpreting sensory impressions. However, the sensory organs are functional and the attention and intellectual abilities are not impaired.

contents

• causes
• Examples
• Different types
• Visual agnosia
• Tactile agnosia
• Spatial agnosia
• Auditory Agnosie
• diagnosis
• therapy

causes

Possible causes of agnosia include brain trauma, brain tumors, meningitis, stroke, cerebral hemorrhage, dementia and severe mental illness. Noxious substances, such as alcohol, drugs and medicines are among the causes. An agnosia can also be innate.

Examples

Affected see a knife or a fork, but do not know what to do with it. However, if they take the objects into their hands, they can, by means of the sense of touch, assign the things not previously recognized. Another manifestation of agnosia is not the recognition of spoken words, sentences or melodies. Some sufferers in turn suffer from the fact that there is a lack of orientation in the room, above and below can not be distinguished, which even transfers to your own body - it is no longer realized where legs and arms are.

Spatial agnosia leads to the disorientation of those affected, which can go so far as to make it impossible to distinguish even up and down even in one's own body. (Image: pathdoc / fotolia.com)

Different types

Depending on which area in the brain is affected, the agnosia is divided into different types.

Visual agnosia

Visual agnosia, also called optical agnosia or soul blindness, triggered by damage to the occipital lobe, is reflected in the fact that those affected see something but can not recognize it. They can not associate their perception with an optical memory. For example, they see a key, but they do not know what to do with it.

There are other sub-forms of visual agnosia: prosopagnosia, associative agnosia, and coloragnosis. In prosopagnosia, also known as blindness, patients are unable to recognize or remember faces. This is a partial performance weakness of the brain. They therefore orientate themselves by the voice, the clothing and the gesture. In the presence of prosopagnosia, those affected may see the humans, but not associate them with a known person.

This disease can be both innate and acquired. In the congenital form, those affected from birth are unable to associate faces with persons. They recognize their own parents by their voice, figure or clothing. They learn to handle it in the course of life. This form of agnosia can be inherited further. Prosopagnosia is sometimes triggered by severe traumatic brain injury, cardiac arrest or stroke. This can only be temporary, but also forever.

Furthermore, injuries in the brain can prevent color processing, which leads to a so-called color diagnosis. The colors are seen but not recognized. The symbolic content of the colors has been lost. For example, the meaning of the traffic light colors no longer exists.

The color-nagging makes it impossible for those affected to assign the symbolic meaning of colors. (Image: fotos4u / fotolia.com)

In associative agnosia, although the shape and the shape of an object are perceived, but this can not be named. Mostly patients are able to trace the object correctly. Eventually associations are created. For example, the object is a clock showing 12 o'clock. The patient does not recognize the clock but says: "Oh it's noon, the food must be ready for the children".

Tactile agnosia

Tactile agnosia affects the sense of touch. Underneath is the inability to recognize things by calling them and calling them by name, although the sense of touch is fully functional. By seeing the objects are recognized and can also be named.

Spatial agnosia

In spatial agnosia the orientation in space is disturbed. (see paragraph "Examples")

Auditory Agnosie

Colloquially, the auditory agnosia is called deafness. Familiar noises such as an airplane or certain music are heard but no longer recognized, although the hearing aid is intact. This type of agnosia can be innate. Especially on the phone, when the recognition of the voice is necessary, problems arise. Here is the caller ID, which today gives almost any phone.

In verbal auditory agnosia, word deafness, patients can hear the words but find them difficult to understand - speech lacks meaning - it is only perceived as noise.

In verbal auditory agnosia have difficulty recognizing words and language. They perceive the sounds only as noises without further meaning. (Image: pathdoc / fotolia.com)

The noise diagnosis does not allow normal everyday and environmental noise to be categorized and assigned correctly. For example, the noise of an engine can no longer be recognized as such. At the same time, direction and distance can no longer be estimated.

Another form of auditory agnosia is affective auditory agnosia. It no longer allows the perception of age, gender and the condition of the interlocutor. Only the factual content is recorded.

diagnosis

To diagnose agnosia, various neuropsychological tests are performed. Further diagnostic procedures are CT (Computed Tomography) and MRI (Magnetic Resonance Imaging). A physical examination is equally important to rule out or recognize that a visual or hearing disorder is present.

therapy

Specific therapy is unknown. Speech therapy, occupational therapy. Conversational or occupational therapy can help patients to compensate for the deficits that have developed through agnosia. For the patients, this is usually quite exhausting. Those who are completely normal for healthy people and, above all, who are automatic, have to focus very much on those affected. The prognosis depends on the type and size of the injury and on the age of the patients. (Sw)
Specialist supervision: Barbara Schindewolf-Lensch (doctor)