A Multidisciplinary Approach to Understanding Developmental Dyslexia Within Working-Memory Architecture: Genotypes, Phenotypes, Brain, and Instruction

Abstract

A unifying theoretical framework of three working memory components provides a systems perspective for discussing past and new findings in a 12-year research program that point to heterogeneity in the genetic and brain basis and behavioral expression of dyslexia: (a) codes for word-form storage and processing, (b) time-sensitive phonological and orthographic loops for maintaining information in working memory or outputting it, and (c) executive functions for language (e.g., rapid automatic switching of attention). Results, which span the genetic to neurological to behavioral levels of analysis, point to possible impairment in any one or combination of these working memory components in individuals with dyslexia. A DNA variation on chromosome 15 may be linked with the phonological word-form in the first working-memory component. A DNA variation on chromosome 6 may be linked with slow rapid automatic switching, inattention ratings, and impaired goal-directed activity ratings in the third working-memory component. Brain and behavioral findings support (a) Triple Word Form Theory: phonological, orthographic, and morphological word-forms and their parts contribute to learning to read and spell words; and (b) Cross-Word Form Mapping: in the process of learning to read and spell words children compute the inter-relationships among the three word-forms and their parts. However, children with dyslexia may require more focus on the morphological word-form and its parts and their relationships with the other two word-forms and their parts than do normal readers. Also, children with dyslexia have unusual difficulties in sustaining phonological loop function in working memory over time; their impaired orthographic loop function may interfere with learning to write alphabet letters and spell, which may be as impaired as word decoding and reading. Impaired executive functions may interfere with the efficiency of working memory in processing oral and written language.

How phonological awareness mediates the relation between working memory and word reading efficiency in children with dyslexia

“…By adding working memory to our model, we were able to control for the working memory component in the phonological awareness task. Our results provided evidence for the argumentation of Berninger et al (2008) that the level of word reading efficiency in children with dyslexia is associated with both phonological awareness problems and working memory. The variation in working memory thus accounts for part of the relation between phonological awareness and word reading efficiency.…”

“…This apparent difference in phonological awareness impairments may partly be due to the increased demand on working memory in more complex phonological awareness tasks (Berninger, 2008). Children with dyslexia show deficits in their working memory, phonological awareness, and word reading efficiency (Berninger, Raskind, Richards, Abbott, & Stock, 2008; Brosnan et al, 2002; Swanson, Zheng, & Jerman, 2009). Working memory predicts both phonological awareness and word reading efficiency (de Abreu, Gathercole, & Martin, 2011; Berninger, Abbott, Vermeulen, & Fulton, 2006; Christopher et al, 2012; Locascio, Mahone, Eason, & Cutting, 2010; Ramscar & Gitcho, 2007).…”

“…In typically developing children, working memory has indeed been found to predict phonological awareness (de Abreu et al, 2011; Oakhill & Kyle, 2000) and word reading efficiency (Berninger, Abbott, Vermeulen, et al, 2006; Christopher et al, 2012; Locascio et al, 2010). Children with dyslexia generally show deficits in working memory and having phonological awareness and word reading efficiency problems (Berninger, Raskind, et al, 2008; Brosnan et al, 2002; Swanson et al, 2009). …”

The modality and redundancy effects in multimedia learning in children with dyslexia

“…Due to a phonological deficit and accompanying working memory problems, children with dyslexia have problems with learning from text (e.g., Berninger, Raskind, Richards, Abbott, & Stock, 2008; Swanson, Zheng, & Jerman, 2009). Multimedia may support their learning by replacing written text with audio or by adding audio to the written text.…”

Reading and Writing Achievement Tests for Assessing Orthographical and Phonological Impairments of Japanese Children with Developmental Disorders

“…Moreover, a longitudinal developmental study showed that both orthographical and phonological skills accounted for independent variance in later orthographic skills (Sprenger-Charolles et al 2003). It has been also suggested that both the orthographic and phonological measures contribute to distinguishing various types of dyslexia (Berninger et al 2008;Coltheart et al 2001;Hultquist 1997;Plaut et al 1996); although dyslexia has been strongly associated with a deficit in phonological processing (Ramus et al 2003;Shaywitz and Shaywitz 2005), reading disabilities may also be linked to problems with orthographic processing. We thus incorporated both orthographical and phonological measures into our reading and writing tests, with the expectation that their inclusion might help us distinguish not only various types of dyslexia but also dyslexia and ADHD.…”