What Is Dyslexia? What Causes Dyslexia?

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Article Date: 27 Apr 2010 - 0:00 PDT

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Dyslexia is a specific reading disability due to a defect in the brain's processing of graphic symbols. Dyslexia is a learning disability that alters the way the brain processes written material.

Two commonly held beliefs about dyslexia are that children with it are prone to seeing letters or words backward, and that the problem is linked to intelligence. Both beliefs are incorrect. The problem is a linguistic one, not a visual one, in dyslexia. And dyslexia in no way stems from any lack of intelligence. People with severe dyslexia can be brilliant.

According to Medilexicon's medical dictionary:

Dyslexia is impaired reading ability with a competence level below that expected on the basis of the person's level of intelligence, and in the presence of normal vision, letter recognition, and recognition of the meaning of pictures and objects.

The effects of dyslexia, in fact, vary from person to person. The only shared trait among people with dyslexia is that they read at levels significantly lower than typical for people of their age. Dyslexia is different from reading retardation which may reflect mental retardation or cultural deprivation.

Dyslexia is thought to be one of the most common learning difficulties. It is estimated that 4-8% of all schoolchildren in England have some degree of dyslexia.

Dyslexia appears to be more common in boys than girls. For example, it is estimated that boys are one-and-a-half to three times more likely to develop dyslexia than girls.

Dyslexia affects people of all ethnic backgrounds, although a person's native language can play an important role. A language where there is a clear connection between how a word is written and how it sounds, and consistent rules grammatical rules, such as in Italian and Spanish, can be more straightforward for a person with mild to moderate dyslexia to cope with.

However, languages such as English, where there is often no clear connection between the written form and sound, as in words such as 'cough' and 'dough', can be more challenging for a person with dyslexia.

What are the symptoms of Dyslexia?

A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.

Symptoms of dyslexia may include expressive language problems or disabilities. When reading aloud, for example, people with dyslexia may reverse words or parts of words. A dyslexic child may read the word "bad" as if it were "dab." Word order and sounds may also be confused, by dyslexics, and words are often omitted or slurred over. "The dog chased the cat down the street" could become "the gob chaled on the treats." Dyslexics may also reverse letters and words in written language. Mirror writing, a complete reversal of words, is sometimes present.

Dyslexia symptoms may also include difficulty with receptive language. Dyslexic people may not correctly perceive sounds or words. Whether reading aloud or silently or listening to spoken language, dyslexic students often cannot recall important details of what has been said or read. People with dyslexia may be unable to process material that is read to them and have difficulty explaining main ideas of material.

In speaking and listening, students with Dyslexia have difficulty pronouncing words, especially those with more than one syllable. Frequently people with dyslexia cannot repeat phrases that are spoken to them. They have difficulty gleaning the meaning from spoken phrases.

Difficulty following instructions is also a symptom of dyslexia. Homonyms, synonyms, rhymes, and idioms are difficult for dyslexics. Dyslexics may also have problems with metaphors, similes, and other symbolic speech.

What are the causes of Dyslexia?

There are a number of different theories about the causes of dyslexia which all tend to agree that it is a genetic condition that changes how the brain deals with information, and that it is passed on through families.

The most widely supported theory of how dyslexia affects reading and writing is known as the phonological processing impairment theory. It is thought that people with dyslexia find phonological processing much more difficult than other people.

It is thought that the reason people with dyslexia have problems with phonological processing is that some areas of their brain function in a different way than in people without the condition.

Magnetic resonance imaging (MRI) scans have shown that activity levels in all three regions of the brain are much lower in people with dyslexia when they are trying to read. These low brain activity levels may contribute to their problems with phonological processing.

The cerebellum is also responsible for coordination, and your ability to estimate how much time has passed. This may explain why many people with dyslexia have problems with coordination and time management.

Dyslexia is also thought to possibly be a genetic condition which means it runs in families. It is estimated that if you have dyslexia, there is 40-60% likelihood that your child will also develop the condition.

Diagnosing Dyslexia

Dyslexia is diagnosed using a complete evaluation including intelligence, educational, and speech/language assessments. The assessments used in diagnosing dyslexia should also include observations, input from teachers and parents, analysis of student work, and developmental and social histories.

During the assessment process, examiners look for evidence of the disorder and also rule out other factors that could be causing the student's reading and language problems. Factors to rule out include, lack of instruction, lack of attendance, social and economic factors, and physical problems such as hearing or vision difficulty.

What are the treatment options for Dyslexia?

The treatment of dyslexia should be directed to the specific learning problems the person has. The usual course is to modify teaching methods and the educational environment to meet the specific needs of the individual with dyslexia.

The prognosis for people with dyslexia is mixed. The disability affects such a wide range of people, producing different symptoms and varying degrees of severity, that predictions are hard to make. The prognosis is generally good, however, for individuals whose dyslexia is identified early, who have supportive family and friends and a strong self-image, and who are involved in a proper treatment program.

Special education services may include specialist help, individualized tutoring, or special day classes. Every individual has different requirements and an Individual Education Plan should be created for each child. Positive reinforcement is important as many students with learning disabilities have poor self-esteem. Psychological counseling may be helpful.

Children with dyslexia learn better when they can use as many different senses as possible. An example of multi-sensory teaching is where a child is taught to see the letter "a," say its name and sound, and write it in the air (all at the same time).

Skills should be reinforced through regular practice because children with dyslexia often have to "overlearn" skills that they have already mastered. This helps to improve their automatic recognition of the correct phonemes, letters, and rules in reading and writing.

Preventing Dyslexia

For those with dyslexia, the prognosis is mixed. The disability affects such a wide range of people, producing different symptoms and varying degrees of severity, that predictions are hard to make.

Learning disorders tend to run in families. The prognosis is generally good, however, for individuals whose dyslexia is identified early, who have supportive family and friends and a strong self-image, and who are involved in a proper remediation program.

For families without a previous history of learning disabilities, an intervention can begin as early as preschool or kindergarten if teachers detect early signs.

Teaching needs to be highly structured, with development made in small steps, building logically on what has been learnt before.

Written by Sy Kraft (B.A.)
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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