What is dyslexia? controversy and consensus

The question ‘What is dyslexia?’ has resulted in considerable debate since the condition was described by W.R. Gowers in 1893 as ‘a cerebral symptom … a peculiar intermitting difficulty in reading’. There are now a number of definitions available in the literature including:

Dyslexia is one of several distinct learning disabilities. It is a specific language-based disorder of constitutional origin characterized by difficulties in single word decoding, usually reflecting insufficient phonological processing. These difficulties in single word decoding are often unexpected in relation to age and other cognitive and academic abilities; they are not the result of generalized developmental disability or sensory impairment. Dyslexia is manifest by variable difficulty with different forms of language, often including, in addition to problems with reading, a conspicuous problem with acquiring proficiency in writing and spelling. (The Orton Dyslexia Society Research Committee, April 1994)

This can be contrasted to the following definition:

Dyslexia is best described as a combination of abilities and difficulties, which affect the learning process in one or more of reading, spelling, writing and sometimes numeracy. Accompanying weaknesses may be identified in areas of speed of processing, short term memory, sequencing, auditory and/or visual perception, spoken language and motor skills. Some children have outstanding creative skills, others have strong oral skills, yet others have no outstanding talents; they all have strengths.

Dyslexia occurs despite normal intellectual ability and conventional teaching; it is independent of socioeconomic or language background. (Peer, 2000)

A working party from the Division of Educational and Child Psychology of the British Psychological Society (BPS) produced this definition:

Dyslexia is evident when accurate and fluent word reading and/or spelling develops very incompletely or with great difficulty. This focuses on literacy learning at the word level and implies that the problem is severe and persistent despite appropriate learning opportunities. (BPS, 1999:18)

Discussion

■ How do these definitions compare with your own understanding of dyslexia?

■ To what extent do the definitions agree about the cause and symptoms of dyslexia?

■ Do these definitions help you to support learners with dyslexia in your educational setting?

As can be seen from the exemplar definitions, there are some elements of consensus about dyslexia that may help those new to the field to understand learners who experience dyslexia. It is important to understand that dyslexic learners are individuals and although they may share some common features of dyslexia, there are wide individual differences. It may be that one learner only exhibits mild difficulties and can have their learning needs met within the context of the mainstream environment, while another learner with dyslexia may require an Individual Education Plan (IEP) in order to secure provision that is ‘additional to or different from’ that provided for their peers (DfES, 2001b: Section 6:59). In looking at the definitions of dyslexia, it can be seen that dyslexia is represented at different levels. These are consistent with the schema described by Morton and Frith in 1993 and 1995. In order to understand dyslexia, it may be helpful to consider ‘levels’ of representation and how they impact upon assessment and learning support for dyslexic learners (Figure 1).

Clearly, dyslexia is not ‘experienced’ at all these separate levels but the level at which dyslexia is represented often influences the choice of support program/ intervention, e.g. a parent may choose to build his/her child’s confidence or may see that he/she needs to ‘protect her child from failure’ by seeking a special school placement whereas a teacher may concentrate on delivering additional support for word level work. The next topic examines in more detail the two levels of representation of dyslexia, biological and cognitive, that impact upon the behavioral level of dyslexia.