Defining Dyslexia

Abstract

We argue against defining dyslexia as requiring by definition the presence of demonstrable phonological difficulty, and also against defining it in relation to exclusion criteria. Instead, we suggest that what matters is evaluating any child's set of reading subskills against age-related norms for those subskills. We also argue that in considering the causes of reading difficulty it is essential to distinguish between proximal cause (some abnormality in the information-processing system that the child is using to read) and distal cause (the reason for this system being abnormal). The same proximal cause (e.g. poor phonic knowledge) can be the product of different distal causes in different children (e.g. the distal cause might be constitutional, environmental, or educational).