Defining Dyslexia, or Not
Elliot presents four definitions of dyslexia for the reader, each having certain affordances and constraints associated with them.
Dyslexia 1, simply put, refers to people who exhibit word-level reading difficulty. Identification and assessment of dyslexia under this definition is relatively straightforward, requiring basic word-reading tests. However, “reading skills are distributed normally in the population with no clear boundary between normal and disabled reading performance. Thus, the location of any cutoff point that could be employed for diagnostic purposes is largely arbitrary” (p. 2). That is, determining who might be considered dyslexic is far less stable than one might expect, and it could include anyone who has difficulty decoding words and reading fluently.
Dyslexia 2 refers to a clinically derived subgroup of poor decoders. Since dyslexia is considered by many to be diagnosable, but often hidden or unrecognizable, “a diagnosis on these lines is typically obtained on the basis of a clinician’s judgment following detailed psychological examination using a range of educational, cognitive, and neuropsychological measures” (p. 2). However, this definition is also problematic. There are currently no meaningful ways of identifying such subgroups within larger pools of those who struggle with decoding, and there are no specialized, differentially appropriate interventions available. At the same time, differential resourcing can lead to uncertain moral and ethical grounds, such as only those with financial resources being able to afford these diagnoses.
Dyslexia 3 refers to people who exhibit a persistent resistance to high-quality intervention using targeted, evidence-based instructional practices. However, with this approach comes the difficulty of knowing just how much intervention is required before a diagnosis could be made. As such, interventions that could support a reader who is experiencing difficulties may not be provided in a timely fashion.
Dyslexia 4 defines dyslexia as people with a “pervasive neuro-diverse disorder that, in its reach, goes far beyond reading difficulties.” This definition is often based on “observations that those with severe reading difficulties are more likely than normal readers to present with various cognitive difficulties.” Yet, there is no consistent evidence of genetic or neurobiological factors that separate readers who are dyslexic from other readers who exhibit reading difficulties.