Alexia and agrafia: types of alterations in written language

The use of language is one of the main capacities of the human being. The fact of mastering it more or less influences how we relate to other people, how we see ourselves and even how we think.

Perhaps that is why there is a side of the neuropsychology She is very interested in language disorders, among which the best known are dyslexia Y aphasias. However, there are also some others, such as alexia and the agrafia.

What is alexia?

In short, alexia is a loss of ability to read correctly that is due to injury to the brain. Therefore, the term alexia refers to a range of reading disorders that are caused by brain damage.

Alexia is distinguished from dyslexia in that in the latter, the reading problems appear without being able to identify wound marks in the neuronal tissue of the brain regions associated with language. If in alexia the disorder appears because of the acquired damage, in dyslexia the explanation has to do more with the way in which the one that the brain develops during childhood, with a genetic component and with a learning dynamic that gives problems. This explains why alexia is also known as acquired dyslexia.

In addition, as it happens in all language disorders, alexia can present in milder and more severe forms in which the person is totally unable to read.

What is agrafia?

Agraphia is the inability to write correctly whose cause is also a brain injury.

Typically, agraphia occurs in conjunction with other language disorders (especially aphasias and alexias). Therefore, the cases of pure agraphia in which the only difficulty related to the language affects the writing and no other ability are very rare.

The types of alexia

As the concept of alexia is very broad, many subcategories are used in neuropsychology and psycholinguistics to differentiate the ways in which this disorder can develop. present and have it easier when intervening on a case-by-case basis (in addition to allowing investigations to be carried out in which different injuries produce different effects).

1. Alexia without agraph, or pure alexia

As the name suggests, pure alexia is used to identify cases in which there is only an inability to read, but not to write. People who experience it see the letters as if they were simple drawings, and they are not able to translate these visual signals into phonemes. Therefore, and although it seems strange, in the cases in which alexia is diagnosed without agraphia, the affected person is unable to understand what he has written.

It is the least common type of alexia, since for this to occur, the lesions have to affect both lobes of the brain and cause the visual information that is collected from the two eyes cannot pass to the left side of the brain to be processed by the language areas, while those involved in the production of written language remain intact and connected between Yes.

2. Alexia with agraphia, or central

People who experience alexia with agraphia have serious problems both reading and writing.

This type of alexia is also known as alexia angularas it affects an area of ​​the brain called the angular gyrus. In the angular gyrus, which is found in the lower part of the parietal lobe (normally, on the left side of the brain), it is responsible, among other things, for performing the conversion of letters into sounds and vice versa, and therefore a lesion that destroys this area or isolates it from the rest of the cortex is very likely to produce alexia with agrafia.

3. Alexia anterior, or frontal

Unlike what occurs in the other two types of alexia, in which the lesion occurs in areas of the brain close to the nape, the anterior alexia is caused by a lesion that mainly affects the frontal lobe, in the area near the temple left. It is an alexia associated with Broca's aphasiaAlthough when talking about frontal alexia, reading problems are usually more serious than those related to the rest of the language functions.

In patients in whom this type of alexia produces milder symptoms, the main difficulties have to do with problems understanding the syntactic relationships between words that are read. When alexia is more severe, they cannot identify words that are spelled to them, or name the letters of a short sentence. However, something that distinguishes frontal alexia from the other two categories is that it is easier to read familiar words in this category.

How can alexia be treated?

Alexias are always caused by lesions in the brain, and therefore any treatment initiative must be supervised by specialists whose field is related to neurology and who can provide a service personalized.

Bibliographic references

• Junqué, C. and Barroso, J. (Coords.) (2009). Neuropsychology Manual. Madrid: Synthesis.
• Moore, M. M., Brendel, P. C., Fiez, J. TO. (2014). Reading faces: Investigating the use of a novel face-based orthography in acquired alexia. Brain and Language, 129, pp. 7-13.
• Pflugshaupt, T., Gutbrod, K., Wurtz, P., Von Wartburg, R., Nyffeler, T., De Haan, B., Karnath, H., Mueri, R. M. (2009). About the Role of Visual Field Defects in Pure Alexia. Brain, 132 (7), pp. 1907 - 1917.