The Cause and Pervasiveness of Dyslexia   

The precise cause of dyslexia is not yet clearly understood scientifically.  Accepted causes include a genetic predisposition and neurologically-based deficiencies in (1) the processing of visual and auditory information and (2) in the processing of a language, particularly phonology.  

Researchers suggest that in English speaking countries, roughly fifteen percent of school children are affected by some form of dyslexia. With early detection, the symptoms of dyslexia, for the most part, can be alleviated. Conversely, when therapy begins later, its effectiveness is usually less dramatic.