Reading-Listening Discrepancy Definitions of Dyslexia

Abstract

In the often cited words of the World Federation of Neurology (1968), specific developmental dyslexia is “a disorder manifested in difficulty in learning to read despite conventional instruction, adequate intelligence, and sociocultural opportunity. It is dependent upon fundamental cognitive disabilities which are frequently of constitutional origin” (Critchley,1970, italics added). As pointed out by Stanovich (1991, 1992, 1994) among others, the ‘unexplained’ and therefore ‘unexpected’ aspects of dyslexia are central to this definition as well as to many of its variants. Dyslexia is ‘unexpected’ in the sense that the learner exhibits a discrepancy between potential (adequate intelligence) and achievement (difficulty in learning to read) (Harris Hodges, 1981, 1995; Harris Sipay, 1980; Skowronek Marx, 1993). If the difficulties in learning to read had obvious causes, such as severe mental retardation, poor vision, deafness or lack of knowledge of the language of the text, there would be little need for a special term, because the difficulties could be diagnosed and treated without reference to reading. The challenge to both dyslexia research and education is this apparent paradox that there are children, young persons, and adults who experience severe difficulties in learning to read for no apparent reason.