A reading disability that is not caused by an identifiable physical problem (such as brain damage, visual or auditory problems).

Dyslexia is a specific learning disability characterized by a significant disparity between an individual's general intelligence and his or her language skills, usually reflected in school performance.

Estimates of people with dyslexia range from 2% to the National Institutes of Health figure of 15% of the U.S. population. It is a complicated disorder with no identifiable cause or cure, yet it is highly responsive to treatment in the form of special instruction. The most obvious symptoms of the dyslexic show up in reading and writing, but listening, speaking, and general organizational skills are also affected. The dyslexic may have trouble transferring information across modalities, for example from verbal to written forms. The dyslexic's characteristic reversal of letters, confusion between similar letters such as "b" and "d," omission of words...