Definitions of Dyslexia
The number and range of definitions for dyslexia can be quickly demonstrated by an internet search.
As yet, there is no universally agreed definition of dyslexia, but the World Health Organisation's definition of "Specific Developmental Dyslexia" produced in 1968 by the World Federation of Neurology remains one of the simplest, focusing upon unexpected literacy difficulties in otherwise able individuals who have had adequate educational, social and cultural opportunities.
"A disorder manifested by difficulty learning to read, despite conventional instruction, adequate intelligence and sociocultural opportunity. It is dependent upon fundamental cognitive disabilities which are frequently of constitutional origin."
The Dyslexia Scotland definition, as published in the Dyslexia Handbook for Adult Literacies in Scotland 2005, is as follows:
"Dyslexia is a specific learning difficulty which affects up to 10 per cent of the population to some degree and is most commonly characterised by difficulties with the acquisition of reading, spelling and writing skills. Frequently, mathematics and aspects of spoken language are affected. Dyslexic people often suffer from auditory processing difficulties, poor organisational skills, poor physical co-ordination and directional confusion. The majority of dyslexic people have poor short-term memory that causes an inability to retain sequences of numbers and words, and instructions to carry out simple tasks. Except for the common difficulty with written language no two dyslexic people exhibit the same range of associated characteristics. Dyslexia affects people across the whole spectrum of ethnicity, socio-economic status and intellectual ability."