Alexia: what is it, types, symptoms, causes and treatment
Jul 16, 2021
The ability to read it is a fundamental skill in today's society. Academic and work life generally require mastery of this skill. That is why since childhood we are learning to give meaning to the words that we form through written language, something that although for an adult it may seem relatively simple if it has been done since childhood requires a high level of processing and a large number of operations and mental transformations to be carried out successfully.
However, sometimes people who have possessed and correctly developed the ability to read lose this possibility for some reason, completely losing the ability to read. This circumstance corresponds to the alexia, which we are going to talk about throughout this article.
- Related article: "The 6 types of visual agnosia and their symptoms"
The alexia: basic definition
Named Alexia A written language disorder characterized by the partial or complete loss of reading ability, this being produced by the appearance of some type of brain injury. It is therefore a secondary type of affectation, that is, derived from another alteration, which can even be interpreted as a symptom of it.
It is considered a type of visual agnosia, that is, the absence of recognition of some type of perceptible stimulation through sight. In the present case, the subject loses the ability to understand written words, being impossible or at least supposing a great difficulty the fact of coding them to be able to transform the spelling into phoneme, although it has previously possessed this capacity.
- You may be interested: "Dyslexia: causes and symptoms of reading difficulties"
Types of alexia
Although alexia implies the loss of reading ability, it does not always appear in the same way, and there may also be other problems or starting from different deficits. Among the main types we can find
Alexia pure or without agraph
This type of alexia is one in which only severe difficulties appear or the complete impossibility of recognition visual letters or words, however the subject can write correctly (despite not being able to understand what he has written). Also called word blindness. A single frequently used word for the subject may be recognized.
It is not the most common, since it usually involves bilateral involvement in such a way that the visual information cannot pass to the areas that interpret and generate language, in the hemisphere left. It usually corresponds to problems in the occipital area of the brain, in fusiform, lingual and / or angular gyrus, or the uncus.
Alexia central or with agraphia
As in the previous case, we find an alteration and impossibility or great difficulty in the recognition of written words, but also in their production. In other words, in this case we find that the subject can neither read nor write. Anomia may also appear, having trouble identifying objects and visual stimuli beyond literacy.
This type of alexia usually corresponds to injuries in the angular gyrus, which is responsible for processing the information of such that the spelling or letters are passed to phonemes or sounds and vice versa, something necessary both to read and to to write. It is also related to lesions in the parietals or in the fibers from the temporal and occipital lobes.
- Related article: "The lobes of the brain and their different functions"
Alexia anterior or with aphasia
Also called frontal alexia, we are facing a circumstance in which there are not only alterations at the reading level but also in the production of speech. In this case, the injury is generally produced at a more frontal level, its functionality being similar to that of a subject with Broca's aphasia. It is usual that there are fewer problems with words familiar to the subject than in comparison to the rest of the alexias.
- You may be interested: "Aphasias: the main language disorders"
Differentiation from other situations
It is important to bear in mind that in alexia we are facing a situation in which the subject previously knew how to read and a loss of said ability, not being considerable like alexia the cases of those people who have never learned to do it, that is, of illiteracy.
It is also relevant to differentiate it from developmental dyslexia, which would be that neurodevelopmental disorder (which implies that at the neuronal level what exists is an atypical organization of the brain development and not an injury itself) in which a reading-writing difficulty appears that appears from the childhood and in which there has never been a greater degree of capacity than the subject expresses at that moment (not being a loss but rather a difficulty).
Finally, it should be noted that the alexia it is not derived from the absence of visual perception proper: the subject can see the words and their eyes work with sufficient precision as to perceive them, the problem being the encoding and transformation of these into something significant.
Alexia is considered to be a type of agnosia and a literacy disorder caused by some type of brain injury. But the causes of such an injury can vary greatly. It must also be taken into account that the injury can appear in different locations of the nervous system, from in the turns angular and / or supramarginal to the fibers from the occipital or temporal lobes, passing through the lingual and fusiform gyrus between others. Among the main causes of the appearance of alexia we can find the following events.
One of the main causes of alexia is the suffering of some type of cerebrovascular accident or stroke, let's talk from ischemia (blockage of the blood vessel that prevents blood from reaching certain areas) or hemorrhage (rupture of the Cup). Depending on the affected areas, death of brain tissue can lead to loss of reading ability.
2. Head trauma
Another classic reason for the appearance of alexia is the fact of having suffered some type of head trauma. Traffic accidents, work accidents or assaults are some of the causes that cause some type of alexia to appear.
3. Dementias and other neurodegenerative disorders
Alexia can appear throughout the deterioration generated by some type of dementia, such as Alzheimer's, or other similar disorders. Depending on the disorder itself, the difficulty, worsening and inability to read can appear at different stages of the disease.
- Related article: "Types of dementias: the 8 forms of loss of cognition"
4. Brain tumor
Another possible cause of alexia is found in the appearance of brain tumors that affect, pinch or compress the brain areas and nerve fibers involved in the reading process.
5. Brain infections
Alexia can also appear before certain infectious processes that end up affecting the brain. Some typical ones are meningitis or encephalitis.
Treatment of alexia
The treatment of alexia is not easy, taking into account that we are facing a phenomenon derived from some type of brain injury, and in fact we may be facing permanent damage. However, this does not imply that it is not possible to achieve different levels of recovery, depending on the injured areas or the degree of involvement of the injury, or on compensation of functions.
The type of treatment will depend on these and other factors, and its performance will require a multidisciplinary team in which disciplines such as neurology or psychology work, in addition to other health or even social specialties.
The first thing is to determine and treat the cause of the appearance of alexia. For the most part, an early diagnosis will allow a better work at the treatment level and can avoid a worsening (for example, if we are facing an infection or a tumor, these can grow and cause more damage).
It will be necessary employ an individualized rehabilitation program, being common the use of speech therapies and different types of cognitive stimulation. Psychoeducation will also be important both for people and for their environment, in order that they can understand what has happened and that they know how to apply different means so that difficulties do not pose a limitation. It may also be important to work on the affective sphere, self-concept and self-esteem, which can be altered by the presence of deficits.
- Junqué, C. and Barroso, J. (Coords.) (2009). Neuropsychology Manual. Madrid: Synthesis.
- Portellano, J.A. (2005). Introduction to neuropsychology. Madrid: McGraw Hill.