Developmental Dyslexia: Past, Present and Future

Abstract

A discrepancy between reading performance and intelligence is generally held to be a defining characteristic of developmental dyslexia. However, intelligence appears not to be an important factor in distinguishing between the reading performance of different groups of poor readers. Some dyslexia researchers have interpreted this null hding as seriously questioning the existence of dyslexia as a disorder independent of general poor reading. I argue that the anti-discrepancy theorists make three conflations of separate issues: research on the cause of poor reading versus research on the cause of dyslexia; phonological deficit as cause of dyslexia versus symptom of dyslexia; research on the causes of dyslexia versus research on the diagnosis or remediation of dyslexia. Once these issues are teased apart, not only does the apparent dilemma disappear, but a new and hitful research perspective is suggested. Insights arising from this wider research perspective should transform our understanding of the underlying cause(s) of dyslexia, inform the development of earlier and better methods of screening and remediation and contribute significantly to the understanding of human cognitive development.

Subgrouping of Korean Readers Based on Reading Achievement and the Relation of Cognitive-Linguistic Variables to the Subgroups

“…This finding is consistent with the study by Vellutino and Scanlon (1987), which provides evidence that cognitive-linguistic variables, such as phonological awareness, phonological memory, and rapid naming are better predictors of reading than general intelligence. Further supporting the findings of this study, previous literature states that cognitive-linguistic skills needed for reading are consistent in both poor readers with low IQ and high IQ (D’Angiulli & Siegel, 2003; Fletcher et al, 1994; Nicolson, 1996).…”

The Proposed Changes for DSM-5 for SLD and ADHD

“…Dyslexia. The proposed removal of the discrepancy criteria in the proposed DSM-5 is also in line with current thinking in the United Kingdom and means that children are no longer identified as dyslexic if they are reading at their chronological age but show a discrepancy with their high IQ (but see Nicolson, 1996, on the significance of IQ in dyslexia). The proposed removal of comprehension from the DSM-5 classification also reflects research from the United Kingdom that identifies comprehension difficulties in poor readers with semantic difficulties (Nation & Snowling, 1998) by contrast with dyslexic children, who rely on their semantic skills to compensate their reading.…”

Revisiting Discrepancy Theory in Learning Disabilities: What Went Wrong and Why We Should Go Back

“…Given that the discrepancy method is thought to better represent the essence of LD, despite many psychometric flaws, it is recommended that this method should be used as the yardstick by which success of a cognitive deficits approach is measured. The idea of utilising positive cognitive indicators as a method of LD identification is not new (e.g., Nicolson, 1996; Spagna, 1998). However, what is urgently needed now is a framework detailing the deficits that accurately predict LD.…”