What Is Developmental Dyslexia?

As there is no clear definition of dyslexia, its incidence cannot be determined. It is estimated that about 15% of children in public schools receive special training for learning problems, and 3% to 5% of them may have dyslexia. Dyslexia is not related to gender, although it occurs more frequently in boys than in girls.

Developmental dyslexia

Developmental dyslexia is a specific type of dyslexia that manifests in the abnormal decoding of words, often caused by congenital speech processing or phoneme recognition defects. Other forms of written language problems, such as spelling, fluency in reading (such as speed and accuracy), and impaired reading comprehension. Dyslexia has no difficulty understanding spoken language.

Basic overview of developmental dyslexia

Children with dyslexia but non-dyslexia may exhibit problems with vocabulary learning. Their problems are often caused by difficulty in understanding written or spoken language or poor cognitive ability.

Pathophysiology and etiology of developmental dyslexia

Developmental dyslexia pathophysiology

Speech processing problems or defects in factor recognition cause defects in the identification, synthesis, memory, and analysis of sounds. Problems in auditory memory, speech perception, and vocabulary naming or vocabulary search are also often one of the causes.

Insufficient ability to learn the derivative rules of written language is often considered part of the dyslexia. For example, impaired children may have difficulty identifying roots or stems, or determine which letter in a word should follow other letters, and have difficulty forming specific pronunciationsphonetic connections, such as vowel forms , Affixes, syllables, and endings.

Dyslexia is thought to be related to intrinsic brain functions, but the actual cause is unknown. And there is a family genetic predisposition. Cerebrovascular accidents, preterm births, and intrauterine complications are all related to dyslexia. Dyslexia is a complete loss of reading ability, and may also be caused by direct brain damage or trauma.

Etiology of Developmental Dyslexia

Dyslexia is mainly caused by specific cerebral cortical dysfunction, which is caused by congenital neurodevelopmental abnormalities. Some speculate that the lesions affect the integration of specific brain functions and their interactions, and there are also signs of asymmetry in the left and right hemispheres, reduced neurons, and a smaller left temporal plane. Most researchers agree that dyslexia is related to the left hemisphere and is responsible for the language connections (Wernick area), sound and speech production (Broca area) of the brain, and the process of connecting these areas through the longitudinal bundle of the brain A functional disorder is associated with the occurrence. Dysfunctions or defects in the angular gyrus, the central region of the cerebral occipital region, and the right cerebral hemisphere may seem to cause problems in recognizing vocabulary. There are also studies suggesting possible cerebellar and vestibular dysfunction, but this has not been confirmed.

Defects in non-verbal processing, such as visual perception, are no longer considered the primary cause of dyslexia, however, abnormalities in visual processing can indeed affect word learning. Slow vision processing is affected, which may cause problems with the ability to visually remember details. It has been suggested that defects in large cell systems cause vision-related problems. The effects of eye movement problems have not been confirmed. In any case, there is no strong evidence to support the visual subtype of dyslexia.

Symptoms and signs of developmental dyslexia

Most dyslexia is discovered when there are learning problems in kindergarten or first grade. However, some phenomena in the preschool age can indicate the existence of dyslexia, such as language retardation, dysphonia, difficulty remembering letters, counting, and color recognition, especially family history of reading and learning disorders. Children with speech processing problems often have the following difficulties: the synthesis of sounds, the rhythm of words, the confirmation of the pronunciation position of words, the division of words into articulatable components, and the reorganization of words in the order of sounds. Delays and hesitations in choosing words (obstacles in finding words), alternative words, naming letters and pictures are often early symptoms of dyslexia. Common short-term (working) auditory memory and auditory sequencing problems.

Many people with dyslexia confuse similar letters and words or visual choices, font recognition, consonant / vowel recognition in words (pronunciation-phonetic connections). Reversal or visual confusion often occurs in lower primary school children. However, most reading and writing reversals occur due to memory retention and recall problems. People with dyslexia forget or confuse names of similarly structured letters and words. Becomes b, m becomes w, h becomes n, was becomes saw, and on becomes no.

Diagnosis of developmental dyslexia

Diagnostic indicators of developmental dyslexia

Students with a history of speech acquisition or use delays who have not improved their vocabulary learning in the middle or end of first grade, or whose reading ability does not reach their expected level of speech or intelligence, should be tested. Generally, the best diagnostic indicator is a student's failure to respond to traditional or typical reading methods in the first grade. Attention retention, visual selective attention, related paired learning (such as the matching of pronunciation and phonetic transcription), and immature and improper use of auditory analysis are often confused with obstacles to the speech processing process. If you have early symptoms and signs (see above) and have a family history, do not take a "wait and see" attitude and you should deal with it in a timely manner.

Because dyslexia is not simply "dyslexia," students who show early vocabulary learning problems need assessments of reading, language, hearing, and cognition for the purpose of identifying the cause (the clinical manifestations of speech processing problems are necessary for diagnosis) and Assign students the most effective coaching method.

Developmental Dyslexia Lookup Mistyping

A comprehensive evaluation tests vocabulary recognition and analysis, fluency (accuracy and speed of vocabulary recognition and paragraph reading), and comprehension of reading or listening. Decoding skills are evaluated by sampling the students' pronunciation and phonological-phonetic synthesis, as well as their ability to synthesize words into words. Reading evaluation must also focus on students 'understanding of vocabulary, word knowledge, thinking and reasoning skills, and students' understanding of the reading process.

Speech and hearing evaluation is a check for defects in spoken and phonetic processing, and this defect has nothing to do with defects in intelligence and phoneme composition. Note that tests of cognitive abilities such as memory and reasoning are also necessary for specific diagnosis.

Psychological evaluation is often used to determine whether there are emotional problems or mental disorders, both of which can increase dyslexia. You need to know in detail if you have a family history of mental illness.

Eye (refraction) and ear (hearing) evaluations should also be performed. Although most pediatric and neurological examination results are not sufficient to diagnose, some signs such as immature neurodevelopment or soft nerve signs are often detected, and neurological examination can rule out other diseases (such as seizures).

The subtype of dyslexia has recently been described in terms of mistypes associated with neuropsychological test results. The subtypes are classified as students with dyslexia that can be divided into distinct groups, which reflects differences in central nervous system function (Table 262-4). The treatment effect can be improved by using specific individualized methods.

Prognosis and treatment of developmental dyslexia

Guidance on recognition of developmental dyslexia

Learning to read is a complex activity that combines word recognition with understanding of words and paragraphs.

Guidance on word recognition can be direct or indirect. Direct instruction is straightforward and unambiguous (eg, separate special reading skills from other reading instructions). Indirect instruction is implicit and unspecified (such as incorporating basic phonetic teaching skills into reading programs as supplementary materials). Reading instruction is also divided into two parts: top-down (teaching children through whole words or whole language) or bottom-up (following the level from pronunciation units to words to sentences, teaching children to read step by step) . The initial guidance for dyslexia was direct and top-down and emphasized techniques for decoding and analyzing words in a letter-speech system. Promote multiple sensory methods. This method involves the integration of whole word learning with sight, hearing, and tactile processes to teach children pronunciation, words, and sentences. It does not advocate typical basic phonetic teaching methods, basic reading schemes, and overall language processes.

Combinatorial skills instruction includes teaching students to form sounds into words, decomposing words into constituent parts of words, and identifying the position of sounds in words. Combined skills for reading comprehension, such as teaching students how to recognize the main meaning, answer questions, distinguish facts and details, and reason reading.

Indirect treatment of developmental dyslexia

Indirect therapy can be used as an alternative or supplement to reading instruction but usually does not include word recognition, decoding or reading comprehension. Methods such as optometry and optics (vision treatment, with colored lenses or low power lenses, etc.), shaping, perception training, auditory integration training, biofeedback, neurosensory integration training and applied sports medicine methods. The scientific basis of most treatment options is insufficient and is not recommended here.

Drug treatments have been proposed but have not been proven. For example, antihistamines and motion sickness drugs have been suggested to improve certain brain function impairments caused by impaired audiovisual vestibular function. Piracetam has also been studied for its ability to improve certain advanced cognitive functions.

Although dyslexia is a lifetime problem and many patients can never reach full reading ability, many people with dyslexia have developed direct reading skills and their functional reading skills have been developed. Compensatory methods, such as the use of recorded text, readers, and scribers, are used to help patients learn at a higher level. If reading problems are related to maturity, then patients may overcome early deficiencies as they mature. However, if there are language impairments or cognitive impairments, reading problems are permanent.