Dyslexia

Dyslexia, the inability to learn to read fluently. No single definition of dyslexia is accepted by all reading specialists. In the United States, federal law governing special education classifies dyslexia as a “specific learning disability” or as a “specific reading disability.” The World Health Organization labels dyslexia a “specific reading disorder,” and other sources label it a “specific language disorder.” However, a central feature of all definitions is an unexpected and substantial difficulty in learning to read. The lack of a commonly accepted definition of dyslexia has caused some educators, physicians, and researchers to avoid using the term altogether.

Because there is no clear and widely held definition of the problem, estimates of the number of persons with dyslexia vary widely. Most researchers have suggested that dyslexia is rare, occurring in 1 to 2 percent of the world’s population. However, others contend that 10 to 20 percent of the population have dyslexia or display dyslexic characteristics. Those arguing for the higher incidence levels also suggest that dyslexia can appear in differing levels of intensity, affecting the reading achievement of some individuals more than others. Dyslexia is usually identified during childhood, but it continues to affect individuals throughout their lives. See also Reading and Education of Students with Learning Disorders.

© 1993-2003 Microsoft Corporation. All rights reserved.