Diseases & Conditions


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Dyslexia


Dyslexia is a specific reading disorder involving difficulty separating single words from groups of words and parts of words (phonemes) within each word.

Dyslexia is a particular type of learning disorder that affects an estimated 3 to 5% of children. It is identified in more boys than girls; however, it may simply go unrecognized more often in girls. Dyslexia tends to run in families.

Dyslexia occurs when the brain has difficulty making the connection between sounds and symbols (letters). This difficulty is caused by poorly understood problems with certain connections in the brain. The problems are present from birth and may cause spelling and writing errors and reduced speed and accuracy when reading aloud. People with dyslexia do not have problems understanding spoken language.

Symptoms and Diagnosis

Preschool children with dyslexia may be late in speaking, have speech articulation problems, and have difficulty remembering the names of letters, numbers, and colors. Dyslexic children often have difficulty blending sounds, rhyming words, identifying the positions of sounds in words, segmenting words into sounds, and identifying the number of sounds in words. Delays or hesitations in choosing words, making word substitutions, and naming letters and pictures are early indicators of dyslexia. Problems with short-term memory for sounds and for putting sounds in the correct order are common.

Many children with dyslexia confuse letters and words with similar ones. Reversing the letters while writing—for instance, on instead of no, and saw instead of was —or confusing letters—for instance, b instead of d , w instead of m , n instead of h —is common. However, many children without dyslexia will reverse letters in kindergarten or first grade.

Children who are not progressing in word learning skills by the middle or end of first grade should be tested for dyslexia.

Treatment

The best treatment for word recognition is direct instruction that incorporates multisensory approaches. This type of treatment consists of teaching phonics with a variety of cues, usually separately and, when possible, as part of a reading program.

Indirect instruction for word recognition is also helpful. This instruction usually consists of training to improve word pronunciation or reading comprehension. Children are taught how to process sounds by blending sounds to form words, by separating words into segments, and by identifying the positions of sounds in words.

Component-skills instruction for word recognition is also helpful. It consists of training to blend sounds to form words, to segment words into word parts, and to identify the positions of sounds in words.

Indirect treatments, other than those for word recognition, may be used but are not recommended. Indirect treatments can include using tinted lenses that allow words and letters to be read more easily, eye movement exercises, or visual perceptual training. Drugs such as piracetam Some Trade Names NOOTROPIL have also been tried. The benefits of most indirect treatments have not been proved and may provide unrealistic expectations and delay the teaching that is needed.

Last full review/revision February 2003

Source: The Merck Manual Home Edition