Today we bring you a very interesting post that aims to make a sometimes unknown disorder like Alexia more attractive and accessible to you.
What is Alexia?
Alexia is a written language disorder characterized by the inability to read caused by a brain injury, usually in the left cerebral hemisphere, which is considered dominant for language.
Thus, when a person suffers a stroke, a brain tumor, a neurodegenerative disease, a traumatic brain injury, or any other type of brain damage, multifocal or diffuse, they may present alterations or difficulties in reading.
Types of Alexias
Shallice and Warrington divide alexias into two distinct typologies:
- Central or aphasic alexias, which are associated with a deficit in higher functions related to reading. That is, the semantic value cannot be visually accessed in a way that prevents the initiation of the oral production process.
- Peripheral alexias, which originate from a deficit in the visual processing of written information or in the visual perception of the word. This group includes pure alexia or alexia without agraphia, attentional alexia, and hemineglect alexia.
Pure Alexia or Alexia Without Agraphia
In the case of pure alexia or alexia without agraphia, it is a classic neurological disconnection syndrome characterized by a reading impairment in which other language functions such as expression, verbal comprehension, and writing are preserved.
Among the main causes of onset of pure alexia or alexia without agraphia are:
- Lesion in the left occipital lobe and the corpus callosum.
- Infarction in the lateral geniculate body and the splenium of the corpus callosum.
- Lesion in the left medial extrastriate visual area.
Likewise, the differential characteristics presented by this type of peripheral alexia are:
- Retention of the ability to write both spontaneously and by dictation.
- Preservation of the ability to spell a word from memory and to recognize it when the observer spells it without any visual channel.
- Identification of letters individually in a text, but inability to read complete words and sentences.
- Sequential and literal reading.
- More pronounced affectation in word length.
Patients with Pure Alexia or Alexia Without Agraphia
What happens in cases of patients with pure alexia or alexia without agraphia is the inability to activate both the semantic route, that is, the one that allows identifying words without needing the correspondences between letters and words; and the phonological route, which allows reading from a grapheme-phoneme conversion.
With the objective not only of recovering the altered communicative functionality of people suffering from pure alexia or alexia without agraphia, but also of promoting the generalization of their daily environment and developing compensatory strategies to cope with residual deficits, there are different speech therapy treatments that, although they will help improve reading level, it will still be slower and more laborious than usual.
To work on phonological and graphemic awareness and, therefore, begin to activate the phonological route, the speech therapist will propose exercises that work on graphemic analysis, the assignment of phonemes to graphemes, and the joining of phonemes, in order to achieve a grapheme-phoneme conversion.
Working on the Lexical Route
In the case that the aim is to work on the lexical route, thus recovering part of the lost visual lexicon and improving access to this lexicon, it can be done through word presentation exercises from different semantic fields, homophone discrimination tasks, differentiation of words from pseudowords, word association, copying and dictation of words, recognition of grammatical categories, or even semantic exercises such as the classification of words based on the semantic field, the association of written words with their respective image, or the description of the semantic attributes of a word.