Authors: Maggie Snowling & Charles Hulme.

Article: Do we really need a new definition of dyslexia? A commentary.

Publication: Annals of Dyslexia (Springer). Published: 25 March 2024 2024 | DOI: 10.1007/s11881-024-00305-y

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We provide a commentary on current debates about the definition of dyslexia. We agree with others that dyslexia is best thought of as a dimensional disorder with the best established causal risk factor being a deficit in phonological processing. Dyslexia is particularly common in children from families with a history of dyslexia and in children with preschool language difficulties. We argue that definitions may differ depending upon their purpose. Traditional discrepancy definitions may be useful for research purposes, but when considering the provision of educational services discrepancy definitions are not useful since all children with reading difficulties require reading intervention regardless of their level of IQ.

The nature and definition of dyslexia have been debated ever since it was first identified at the close of the nineteenth century (Kirby & Snowling, 2022). Among the early pioneers, perhaps, it was Samuel Orton’s description of the condition that is closest to current understanding. Although Orton is usually remembered for his attempt to explain the ‘twisting of symbols’ observed in the reading and writing of children with dyslexia, he also documented the familial nature of the disorder, and the tendency for family members to show deficits not necessarily in reading or writing but frequently in speech and language. Here, we will reflect on the points raised by Catts and Petscher and Wolf and colleagues and propose that it is critical for a definition of dyslexia to be evidence-based, and useful in guiding research and practice. Our commentary draws on our longitudinal studies of reading and provides a UK perspective on definitions of dyslexia.

In our view, the broad form of a definition of dyslexia is clear and needs little by way of revision. We believe the core of the definition proposed by the UK Rose Review remains useful and accurate (Rose, 2009).

Tagged as: definition of dyslexia, diagnosis, and phonological deficit


Snowling, M., Hulme, C. Do we really need a new definition of dyslexia? A commentary. Ann. of Dyslexia (2024).