Dyslexia
Dyslexia is a written language learning disability. Along with dysphasia, dyspraxia or dyscalculia, it is part of specific learning disorders. This disorder can affect children normally attending school with no sensory problem (hearing, vision), intellectual disability, or neurological injury. On the other hand, these children suffer from a written language disorder with a reading delay of at least 18 months.
Dyslexia can lead to social, behavioral or anxiety problems beyond learning to read difficulties.
It exists three types of dyslexia : phonological dyslexia, surface dyslexia and mixed dyslexia.
La phonological dyslexia is characterized by a difficulty in “deciphering” the words (see box). The surface dyslexia corresponds to a difficulty in recognizing a word as a whole. The mixed dyslexia combines the two types of dyslexia mentioned above.
To better understand the processes at play in dyslexia: how do you read? According to many studies, reading is the product of two skills: identification of written words and comprehension. The dyslexia would be due above all to a problem of identification of the written words, even if the problems of comprehension remain present. To read a word, there would be two processes:
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Prevalence
Dyslexia would affect 5% of children. Almost 1% of them are said to have a severe disability.
Diagnostic
Screening for dyslexia should be precocious but it cannot be done formally before 18 months of learning to read. He is multidisciplinary. The child can be spotted by his teacher. Certain signs such as poor pencil holding, refusal to write, illegible handwriting or sloppy work should alert people.
The teacher can offer a medical consultation, the doctor then directing him to a Speech Therapist, a remedial teacher and a psychologist. The Reference Centers for Learning Disorders (CRDTA), made up of a multidisciplinary team and present in many regions, can also make a diagnosis of dyslexia.
Various global tests of cognitive functions (memory, attention, etc.), reading and language are offered. We can cite the screening tool Odedys or test duThumb, short text which allows, from the reading time and the number of errors, to estimate the severity of dyslexia.
Eye, hearing and neurological exams are also performed. Just like psychological tests. They make it possible to eliminate other parameters which may be responsible for reading difficulties. This comprehensive assessment will determine whether or not dyslexia is present.
Causes
The causes of dyslexia are still poorly understood. Several scientific hypotheses are advanced1w. The phonological theory admits the greatest consensus. According to this theory, people with dyslexia suffer from a disorder in the representation and mental manipulation of speech sounds. The visual theory suggests that some children have visual-attentional disorders. Finally, a problem of neuron migration is sometimes involved. The neurons involved in reading originate in a non-specific area of the brain and then migrate to the area of the brain dedicated to reading. In dyslexics, this migration would not occur normally.
These anomalies could begenetic origin (family history is common in dyslexia) but this has yet to be confirmed2. Some researchers have found an abnormality in chromosome 15, others in chromosome 18.
Associated disorders
Children with dyslexia almost always have associated dysorthography (difficulty in spelling). Dyslexia is also linked, in more than half of cases, to oral language disorders that appeared in early childhood.3.
Dyslexia is said to increase the risk of suffering from hyperactivity and attention disorders (ADHD)4. We can find problems of memorization, coordination or lateralization.
Consequences
The consequences are very variable depending on the severity of the disorders. Children with dyslexia often encounter academic difficulties which can result in discomfort, aggression or inappropriate behavior.
In France, dyslexic children benefit from a Personalized School Project (PPS). This document allows parents, teachers, rehabilitators and the child to establish a project together. The latter specifies the procedures for the child’s schooling and the necessary arrangements (computer, additional time, etc.). It lists and articulates all the pedagogical, educational, medical and paramedical actions undertaken with the child.