Alexia, the acquired inability to read

Alexia is perhaps one of the disorders that draws the most attention due to its consequences. It was first described in 1881 by the French neurologist Joseph Jules Dejerine. He did it after studying a patient with a stroke; symptoms manifest in impaired reading ability after of an injury.

It is important to differentiate alexia from a developmental or learning disorder. The inability to read is acquired, meaning that after an injury, a person who could read perfectly stops being able to do so.

It seems difficult for this to happen if eyesight is not damaged, but reading is not reduced to one sense. Human beings have specific areas of the brain that are oriented to processing text – both in form and content – and their integrity is essential.

Types of Alexia

This acquired disorder can be accompanied by other neuropsychological conditions, depending on the type of injury and also the language faculties affected. In principle we can establish four types of alexia:

Literal (with agraphia). The patient loses the ability to read and write, since he cannot recognize letters. This loss correlates with parietotemporal damage to the left hemisphere, especially involved in language.Pure (without agraphia). The subjects can write and recognize letters, but cannot sequence them correctly to form words.Frontal. Mainly related to Broca’s aphasia. Patients have ungrammatical and poorly sequenced reading.Space. It consists of the appearance of reading defects due to spatial alterations. This type of alexia usually appears when there is a lesion of the right hemisphere and therefore the spatial components of reading are directly affected.

Types of injury that lead to alexia

We have already seen the various classifications according to the symptoms and the degree to which reading is affected. Likewise, functions are not as delimited in a brain as countries are on a map, so when there is an injury, various functions are affected. In general terms, alexia appears in the following lesions:

right parietal. Alexia and spatial agraphia.left parietal. Alexia and global agraphia.Left temporal. Alexia without agraphia. Damage to posterior cerebral artery. Produces verbal alexia. Damage to middle cerebral artery (angular branch): Alexia with agraphia.

Main symptoms

literal alexia

Since the lesion usually occurs at the parietotemporal level, said alexia manifests itself concomitantly with agraphia. The problems are evident in reading, both aloud and soft.

This type of alexia encompasses a general inability to recognize symbolic language codes, such as musical and/or written. Although patients make an effort to write some letters, they cannot structure them in an order that allows writing..

Pure Alexia

This alexia is characterized by not having agraphia, therefore the ability to write is maintained. Likewise, this function is made more expensive, since the patient can write, but cannot read what he writes.

The injuries are usually occipital and, although patients can read the letters of the alphabet, it is impossible for them to articulate them.

Frontal Alexia

As its name suggests, it usually appears in frontal lesions. Unlike in pure alexia, Patients can read some words, but cannot identify the letters that make up those words.

The writing is therefore usually also deficient, skipping letters and important grammatical signs.

Space Alexia

Consequence of damage to the right hemisphere, responsible for spatial processing. Patients cannot organize their gaze to achieve a reading.

In summary, They cannot stay in a line or follow the spatial order of the words (from left to right). At the same time, spatial hemineglect occurs, therefore the patient does not recognize most of the stimuli on the left side.

Possible causes

Strokes. Damage or occlusion of an artery results in lack or excess of irrigation.Neurodegenerative diseases. The loss, damage or degeneration of tissues is a main component of dementias such as Alzheimer’s or Parkinson’s, where there is usually alexia.Tumors. Most brain tumors produce pressure and alteration of brain metabolism, thus damaging tissues.Head trauma. Accidents and knocks can lead to alteration of the reading if any of the mentioned structures are damaged.

Diagnosis

The first indication for a diagnosis is the area where the damage or injury occurred. Based on that, neurologists and neuropsychologists will apply tracking and specific tests. These tests usually consist of reading, naming, and spatial order tasks..

Tracking: First tests that attempt to stipulate to what degree reading ability is affected. They are quick and general tests that aim to give clues about symptoms.Specific: Depending on the type of injury and the result of the screening tests, specific tests will be applied to determine the type of alexia present in the patient.

Treatment

Treatment is usually multidisciplinary in nature, with strategies that include the work of various professionals such as psychologists, speech therapists, neurologists, neuropsychologists. Although the brain damage identified is permanent, the intervention facilitates new strategies so that the patient has the greatest possible functionality. To achieve this, although there are guidelines and protocols, any intervention must be adapted to the circumstances of each person.

In this sense, the Cognitive stimulation and psychoeducation are two frequent ingredients in the majority of interventions that have been carried out successfully.. Furthermore, the most self-sufficient interaction possible of the subject with his or her environment is an objective shared by all interventions.

It should be noted that technological advances allow this disorder to be addressed more efficiently through applications and virtual reality. Nonetheless, Any health professional or person close to a patient with alexia should do the exercise of looking at a written word and imagining not being able to read it.. It is something as simple as it is important to empathize and understand the emotions and thoughts derived from said difficulty or disability.

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