Dyslexia: 1965–2005

Abstract

William Yule's many contributions to the field of reading disabilities over the last 40 years are reviewed and set in the context of recent research evidence. The value of regression methods in the measurement of reading performance remains valid, but spelling, as well as reading, difficulties need to be assessed in relation to the diagnosis of dyslexia. Although categorical approaches to diagnosis are needed for some purposes, it is likely that the genetic liability to dyslexia is dimensional. Overall, Yule's identification of the key features of specific reading retardation have been confirmed by subsequent research, but the concept of general reading backwardness as a diagnosis has proved less meaningful. The identification of the high rate of comorbidity between reading disability and emotional/behavioural disturbance, highlighted by Yule 35 years ago, has been amply confirmed but the causal mechanisms remain ill-understood.

Research studies on dyslexia: participant inclusion and exclusion criteria

“…Our review shows that many studies report a variety of exclusionary criteria, although some authors consider this practice as inadequate (e.g., Rutter and Maughan 2005;Fletcher 2009). Interestingly in most of the cases we examined, the criteria were reported as characteristics of the sample (e.g.…”

Continuities and discontinuities in psychopathology between childhood and adult life

“…Over the years, there has been some controversy over the concept of dyslexia as a categorically distinct condition (see Démonet, Taylor, & Chaix, 2004; Rutter & Maughan, 2005). The adult outcome findings clearly indicate that the presence of a substantial reading disability in middle childhood/early adolescence constitutes an impairment that shows a high degree of persistence into adult life.…”

Specific Disorders and Broader Phenotypes: The Case of Dyslexia

“…The distinction between domain-specific and domain-general learning problems has been the focus of debate in the field of reading disorders, as much for practical as for theoretical reasons (Stanovich, 1994). In terms of etiology and outcome, the distinction between specific reading difficulties that are unexpected given a child's general cognitive ability (dyslexia) and general reading problems in the context of widespread learning problems has validity (Rutter & Maughan, 2005). Nonetheless, the use of IQ criteria to differentiate subgroups of failing readers (e.g., Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, DSM-IV, American Psychiatric Association, 1994) has declined because, at the cognitive level of description, the two groups share deficits in phonological processing (Stanovich & Siegel, 1994;Swan & Goswami, 1997), and they make equivalent response to reading intervention programmes targeting decoding skills (Hatcher & Hulme, 1999;Shaywitz, Fletcher, Holahan, & Shaywitz, 1996).…”