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The sense organs are extremely important elements of the human body. It is through them that we receive various stimuli from the world, communicate with the environment, learn and gain various experiences. Sometimes, however, the perception of stimuli is impossible for various reasons. This is the case, for example, when we are affected by certain diseases and conditions. One of them is agnosia. What is it characterized by? What types of agnosia do we distinguish? What are its causes and how can this condition be treated?
What is agnosia?
Agnosia is a type of disease characterized by disturbances in the perception of various sensory stimuli. Interestingly, it is not related to the malfunctioning of the organs that are responsible for the senses, but it occurs even when they are fully functional. The problem is therefore not related to the organs themselves, but to the centers in the brain that are responsible for processing and receiving stimuli that come to them. Agnosia can take many different forms and the reasons for its occurrence can be different. It can also apply to people of all ages. The name “agnosia” comes from a Greek word that means ignorance or ignorance and was first used in a medical context in 1891 by Sigmund Freud.
What are the causes of agnosia?
As already mentioned in the previous paragraph, agnosia can have many different causes, most often associated with various diseases and conditions that lead to the destruction of cortical fragments of the brain. Most often, agnosia is caused by head injuries, brain hypoxia, neurodegenerative diseases, tumors of the central nervous system, as well as intracranial bleeding. In addition, agnosia can also occur as a result of stroke, poisoning (including carbon monoxide) and infections of the central nervous system. An example of such an infection is encephalitis.
What types of agnosia are there?
Agnosia is divided into three basic groups that are related to the senses they relate to. We distinguish between auditory and visual agnosia and sensory agnosia. However, these groups are divided into subsequent subgroups.
What is auditory agnosia?
Auditory agnosia can proceed in different ways. When a patient does not hear any sounds in his environment, it is referred to as the so-called cortical deafness. However, it is also possible to selectively receive or not receive auditory stimuli. For example, in some people, auditory agnosia is not recognized as speech, while in others it only affects complex sounds such as music.
What is visual agnosia?
The course of visual agnosia may also vary. When a patient loses the ability to recognize colors, it is referred to as achromatopsia. When the organ of sight reacts improperly to objects that are in motion, this type of agnosia is called akinetopsia. It is also possible that the patient does not recognize the face, even of people close to him. Such a condition is identified as prosopagnosia. Within the scope of visual agnosia, there are also alexia (not recognizing letters and texts), simultanagnosia (connected with selective focus on only one object) and spatial agnosia, in which the patient does not recognize his surroundings.
What is sensory agnosia?
Like visual agnosia and auditory agnosia, also sensory agnosia can proceed in various ways. One of its types is the inability to recognize the shapes of different objects. Interestingly, this applies to both items that are new to the patient and those that they have come into contact with before.
The remaining types of agnosia
In addition to the agnosia mentioned above, there are also those that are related to more than one sense. One of them is anosognosia, i.e. a disorder in which the patient is unaware that he or she has some kind of sensory disturbance. An interesting type of agnosia is autotopagnosia, when a sick person is unable to recognize individual parts of his body.
How is agnosia treated?
The treatment of agnosia depends on the type of agnosia in the patient and, above all, on the immediate cause of the disease. Thus, agnosia itself is not treated, but central nervous system diseases, tumors and infections. Agnosia is often cured when the cause of its occurrence has been cured, but this may not always be the case. Sometimes agnosia lasts long after healing, and sometimes the damage to the brain is permanent. Long-term agnosia is sometimes tried to be healed with the help of various exercises, such as speech therapy and visual exercises.