Dyslexia in children: causes, symptoms, diagnosis, treatment

Dyslexia is a general term describing primary reading disorders. Diagnosis includes examination of intellectual abilities, academic performance, speech development, health status, and psychological examination. Treatment of dyslexia is aimed primarily at correcting the educational process, including teaching recognition of words and their components.

There is no generally accepted definition of dyslexia, so its prevalence is unknown. Some researchers estimate that 15% of children attending mainstream schools receive special correction for reading problems, and half of these may have permanent reading disorders. Dyslexia is more common among boys, but gender has not been proven to be a risk factor for developing dyslexia.

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Cause and pathophysiology of dyslexia

Problems with the phonological process cause impairments in recognizing, combining, remembering, and analyzing sounds. Dyslexia may involve impairments in both writing and understanding written language, which is often limited to problems with auditory memory, speech production, naming objects, or finding appropriate words. Basic impairments in verbal speech are also common.

There is a tendency for dyslexia to run in families. Children from families with a history of reading disabilities or developmental disabilities in scholastic skills are at higher risk. Because changes in the brains of people with dyslexia have been identified, experts believe that dyslexia is primarily a consequence of cortical dysfunction due to congenital abnormalities in the development of the nervous system. Impaired integration or interaction of specific brain functions is also suggested. Most scientists agree that dyslexia is left-hemisphere related and involves abnormalities in the areas of the brain responsible for speech perception (Wernicke's area) and motor speech (Broca's area), as well as abnormal connections between these areas via the arcuate fasciculus. Dysfunctions or defects in the angular gyrus, middle occipital area, and right hemisphere cause problems with word recognition. Inability to learn the rules of word formation when reading printed text is often considered part of dyslexia. Such children may have difficulty determining the root of a word or the gender of a word, as well as determining which letters in a word follow which.

Reading problems other than dyslexia are usually caused by language comprehension difficulties or low cognitive abilities. Visual-perceptual problems and abnormal eye movements are not considered dyslexia. However, these problems may affect word learning later in life.

Symptoms of Dyslexia

Dyslexia may manifest as delayed speech development, difficulty with articulation, and difficulty remembering the names of letters, numbers, and colors. Children with problems with phonological processing often have difficulty combining sounds, rhyming words, determining the position of letters in words, and separating words into pronunciable parts. They may reverse the order of sounds in words. Delay or hesitation in selecting words, substituting words, or naming letters and pictures with similar configurations is often an early sign. Impairments in auditory short-term memory and auditory sequencing are common.

Less than 20% of children with dyslexia have trouble matching their vision to the demands of reading. However, some confuse letters and words with similar configurations or have difficulty visually selecting or identifying patterns of sounds and their combinations (sound-symbol associations) in words. Symbol reversals or misperceptions may occur, most often related to memory and retrieval difficulties, causing children to forget or confuse the names of letters and words with similar structures; thus d becomes b, m becomes w, h becomes n, was becomes saw, on becomes po. However, this may be normal in a child under 8 years of age.

Diagnosis of dyslexia

Most children are not identified as having a disorder until they enter kindergarten or school, where they begin to learn symbols. Children with delays in passive or active language who are not catching up with their peers by the end of the first grade level or who are not reading at the level expected for their verbal or intellectual abilities at any grade level should be evaluated. Often the best diagnostic clue is the child's failure to respond to traditional or typical approaches to reading in the first grade level, although wide variability in reading skills may be seen among children at this level. Diagnosis requires evidence of problems with phonological processing.

Children suspected of having dyslexia should undergo an assessment of reading skills, language development, hearing, cognitive abilities, and psychological evaluation to determine their functional characteristics and preferred forms of education. Such an assessment may be conducted at the request of the child's teacher or parents under the Individuals with Disabilities Education Act (IDEA), a special education law in the United States. The results of the assessment then help determine the most effective approaches to educating the child.

The assessment of reading comprehension is aimed at determining the recognition and analysis of words, speech proficiency, understanding of read and listened to speech, as well as the level of understanding of vocabulary and the reading process.

The assessment of pronunciation, language and listening comprehension allows us to assess spoken language and the impairment of phoneme perception (sound elements) of spoken language. The function of active and passive speech is also assessed. Cognitive abilities (attention, memory, reasoning) are also examined.

Psychological examination is aimed at identifying emotional aspects that may aggravate reading disorders. It is necessary to collect a complete family history, including the presence of mental disorders and emotional disturbances in the family.

The doctor should ensure that the child has normal vision and hearing, either by screening or by referring the child for hearing and vision testing. A neurological examination can help identify secondary signs (such as neurodevelopmental immaturity or minor neurological impairment) and rule out other problems (such as seizures).

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Treatment of dyslexia

Although dyslexia remains a lifelong problem, many children develop functional reading skills. However, some children never achieve adequate literacy skills.

Treatment consists of instructional interventions, including direct and indirect instruction in word recognition and word component skills. Direct instruction involves the use of specific phonics techniques separate from reading instruction. Indirect instruction involves the integration of specific phonics techniques into reading programs. Approaches may include teaching reading with whole words or phrases, or approaches that use a hierarchy of acquisition from learning sound units to whole words to sentences. Then, multisensory approaches are recommended, including learning whole words and integrating visual, auditory, and tactile sensations to teach sounds, words, and sentences.

Teaching word-part recognition skills includes blending sounds to form words, separating words into their component parts, and determining the location of sounds in words. Word-part recognition skills for reading comprehension include identifying main ideas, answering questions, identifying facts and details, and reading with inferences. Many children benefit from using a computer to help them identify words in text or to help them understand words when reading written language.

Other treatments (e.g. optometric training, perceptual training, visual-auditory integration training) and drug therapy have unproven efficacy and are not recommended.