Thoughts on the definition of dyslexia: More on the ongoing debate re the definition of dyslexia - #dyslexia #SLD #schoolpsychologists #schoolpsychology #SPED #reading

Thoughts on the Definition of Dyslexia.  Annals of Dyslexia (click here to read or download - open access)

Linda S. Siegel,  David P. Hurford, Jamie L. Metsala, Michaela R. Ozier, & Alex C. Fender

Abstract 

The International Dyslexia Association's current definition of dyslexia was approved by its Board of Directors on November 12, 2002. After two decades of scientific inquiry into the nature of dyslexia, it is time to reconsider and potentially revise the definition in light of what has been learned. We propose a definition of dyslexia based on its essential nature. Dyslexia is a specific learning disability in reading at the word level. It involves difficulty with accurate and/or fluent word recognition and/or pseudoword reading. We also suggest that the definition should focus solely on dyslexia's core features and should not include risk factors, potential secondary consequences, or other characteristics. Until those factors can reliably differentiate between those with and without dyslexia at an individual level, they should not be included in the definition.

Research Byte: Co-Occurrence and Causality Among #ADHD, #Dyslexia, and #Dyscalculia - #SLD #schoolpsychology #sped #genetics #EDPSY

Co-Occurrence and Causality Among ADHD, Dyslexia, and Dyscalculia

Published in Psychological Science.  Click here to access PDF copy of article

Abstract

ADHD, dyslexia, and dyscalculia often co-occur, and the underlying continuous traits are correlated (ADHD symptoms, reading, spelling, and math skills). This may be explained by trait-to-trait causal effects, shared genetic and environmental factors, or both. We studied a sample of ≤ 19,125 twin children and 2,150 siblings from the Netherlands Twin Register, assessed at ages 7 and 10. Children with a condition, compared to those without that condition, were 2.1 to 3.1 times more likely to have a second condition. Still, most children (77.3%) with ADHD, dyslexia, or dyscalculia had just one condition. Cross-lagged modeling suggested that reading causally influences spelling (β = 0.44). For all other trait combinations, cross-lagged modeling suggested that the trait correlations are attributable to genetic influences common to all traits, rather than causal influences. Thus, ADHD, dyslexia, and dyscalculia seem to co-occur because of correlated genetic risks, rather than causality.

 

What is #dyslexia?— An expert delphi consensus on #dyslexia definition, #assessment and #identification—-#SLD #dyslexia #SPED #schoolpsychology

An open access journal article that can be downloaded for reading.  Click here to access/download

ABSTRACT 

This paper discusses the findings of a Delphi study in which dyslexia experts, including academics, specialist teachers, educational psychologists, and individuals with dyslexia, were asked for their agreement with a set of key statements about defining and identifying dyslexia: why it should be assessed and how and when this assessment should be conducted. Two rounds of survey responses provided a vehicle for moving towards consensus on how to assess for dyslexia. Forty-two consensus statements were ultimately accepted. Findings suggested that assessment practice should take account of risks to the accurate identification of dyslexia. An assessment model, with guidelines for assessors, is presented, based on the Delphi's findings. This hypothesis-testing model requires assessors to investigate and weigh up the factors most likely to result in an accurate assessment before reaching conclusions, assigning terminology, and making recommendations for intervention and management.

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Research bytes: Three interesting reading research articles

New articles on silent reading interventions, skills involved in silent reading, and definition and components of orthographic knowledge. Click images to enlarge

 

 

 

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Research byte: Cognitive-neuro models of reading: A meta-analysis

Excellent research synthesis study that relates cognitive models of reading ability/disability to brain regions. Awesome use of colors and figures to demonstrate research results Click on images to enlarge.

 

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Research byte: Rise time perception and reading disabilities

Another article implicating auditory temporal processing abilities and readind disabilities...rise time perception problems.

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Comments on Proposed DSM-5 SLD Criteria: Colker, Shaywitz, Shaywitz & Simon

A copy of the following paper found its way to my inbox over the 4th of July holiday. It is written by Colker, Shaywitz, Shaywitz & Simon.

Comments on Proposed DSM-5 Criteria for Specific Learning Disorder from a Legal and Medical/Scientific Perspective



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Research bytes: Recent dyslexia research--Annals of Dyslexia

Daigle, D., Berthiaume, R., Plisson, A., & Demont, E. (2012). Graphophonological processes in dyslexic readers of French: A longitudinal study of the explicitness effect of tasks. Annals of Dyslexia, 62(2), 82-99.

Deacon, S. H., Cook, K., & Parrila, R. (2012). Identifying high-functioning dyslexics: is self-report of early reading problems enough? Annals of Dyslexia, 62(2), 120-134.

Kast, M., Baschera, G. M., Gross, M., Jancke, L., & Meyer, M. (2012). Computer-based learning of spelling skills in children with and without dyslexia (Vol 61, pg 177, 2011). Annals of Dyslexia, 62(2), 135-136.

SuarezCoalla, P., & Cuetos, F. (2012). Reading strategies in Spanish developmental dyslexics. Annals of Dyslexia, 62(2), 71-81.

Wijnants, M. L., Hasselman, F., Cox, R. F. A., Bosman, A. M. T., & VanOrden, G. (2012). An interaction-dominant perspective on reading fluency and dyslexia. Annals of Dyslexia, 62(2), 100-119.



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Re

Meta-analysis continues to confirm importance of phonemic awareness in reading...but...lets not overestimate the importance

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Meta-analysis like this one are powerful studies that confirm the importance, in this case, for phonemic awareness (Ga-PC per CHC theory) for reading and dyslexia. However I believe that often the individual studies used as the bases of meta-analysis may overstate the importance of particular abilities due to the well-known problem of specification error in each studies design. I've blogged about this previously and won't take up bandwidth reiterating the importance of recognizing how specification error can cloud accurate interpretation of studies. The long and short of the issue is that manly reading and dyslexia studies during the past two decades have suffered from specification error....by only including indicators of the "hot and sexy" ability constructs in reading research and failing to include measures of known abilities that are also important in reading.

As a result of the "missing variable" problem, individual studies and, in this case, a meta-analysis of studies, most likely overstates the importance of the selected abilities analyzed...in this case phonemic awareness. For example, a recent synthesis by McGrew & Wendling (2010) demonstrated that other abilities often not included in the extant reading disability research (e.g., processing speed; associative memory; lexical knowledge) are important. If measures of these important reading-related abilities had been included in the studies summarized by this meta-analysis most likely the magnitude (effect sizes) of phonemic awareness would be lowered.

Yes...phonemic awareness (Ga-PC) is clearly important...but I caution readers to take the magnitude of the importance with a grain of salt as it is most likely somewhat less if all important reading-related variables had been included in the studies that are combined in this review



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The NeuroDys collaborative dyslexia project in Europe

The project NEURODYS has started as a major new European effort to clarify the biological bases of developmental dyslexia, or specific reading disability. Info can be found here.

Number 1 at IQ Brain Clock blog: Metronome-based training improves reading

I was curious what the most frequently visited post was at my IQ Brain Clock blog was. The winner is.....drum roll.....Metronome-based training improves reading.



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Research Byte: Prevalence and emergence of late emerging poor readers

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Research Bytes: Gs, Glr (RAN), Ga and magnocellular processing and dyslexia

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Research brief: Orthographic processing and dyslexia

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Research bytes. Multivariate prediction of dyslexia with efficient battery

Interesting study demonstrating effective multivariate prediction of dyslexia. Click on images to enlarge.












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Cognitive efficiency measures as the brain's cognitive thermometer

Yet on more study linking poor global processing speed (Gs) with a clinical disorder, this time reading (again). It is very clear that during the past decade one of the most robust research findings (based on the relations between psychometric measures of abilities and all kinds of clinical disorders) is the importance of "cognitive efficiency" in identifying individuals with a wide variety of disorders.

The CHC domains of processing speed (Gs) and working memory (Gsm-WM) have repeatedly been found to be strong indicators that something is wrong in cognitive function, across many clinical disorders. I like to describe measures of cognitive efficiency (Gs+Gsm) as brain thermometers. They can tell you that the cognitive system is not operating efficiently, but they lack specificity to make specific differential diagnoses. Cognitive efficiency markers are domain-general re: Dx.

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intelligence IQ tests IQ testing IQ scores CHC intelligence theory CHC theory Cattell-Horn-Carroll human cognitive abilities psychology school psychology individual differences cognitive psychology neuropsychology neuroscience psychology special education educational psychology psychometrics psychological assessment psychological measurement IQs Corner general intelligence g attention controlled attention executive attention Gsm short-term memory working memory executive functions processing speed dyslexia cognitive efficiency cognitive thermometer brain thermometer

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Research bytes: What works for struggling readers--A best-evidence synthesis

Slavin, R. E., Lake, C., Davis, S., & Madden, N. A. (2011). Effective programs for struggling readers: A best-evidence synthesis. Educational Research Review, 6(1), 1-26.

This article reviews research on the achievement outcomes of alternative approaches for struggling readers ages 5–10 (US grades K-5): One-to-one tutoring, small-group tutorials, classroom instructional process approaches, and computer-assisted instruction. Study inclusion criteria included use of randomized or well-matched control groups, study duration of at least 12 weeks, and use of valid measures independent of treatments. A total of 97 studies met these criteria. The review concludes that one-to-one tutoring is very effective in improving reading performance. Tutoring models that focus on phonics obtain much better outcomes than others. Teachers are more effective than paraprofessionals and volunteers as tutors. Small-group, phonetic tutorials can be effective, but are not as effective as one-to-one phonetically focused tutoring. Classroom instructional process programs, especially cooperative learning, can have very positive effects for struggling readers. Computer-assisted instruction had few effects on reading. Taken together, the findings support a strong focus on improving classroom instruction and then providing one-to-one, phonetic tutoring to students who continue to experience difficulties.


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Neuropsychological abilities related to early written language expression

Very interesting study on the neuropsychological constructs related to beginning writing. The abstract, initial CFA/SEM model, and the final CFA/SEM model are presented below. The initial model was not found plausible due to significant multicolinearity between a number of the measures (variance from some measures could be perfectly predicted from other tests, either singly, or in linear combination with other measures). Most intriguing conclusion for me is the clear importance of executive functioning (very broadly operationalized in the final model) for beginning writing. A good article for this interested in early writing and writing disabilities to get and digest.

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intelligence IQ tests IQ testing IQ scores CHC intelligence theory CHC theory Cattell-Horn-Carroll human cognitive abilities psychology school psychology individual differences cognitive psychology neuropsychology psychology special education educational psychology psychometrics psychological assessment psychological measurement IQs Corner general intelligence working memory Grw reading dyslexia Gf Gc language Ga phonological processing orthographic processing written expression dysgraphia

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Research bytes: WISC-IV ADHD/DCD, rapid serial naming & reading, auditory temporal processing & dyslexia

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Research byte: Phonological awareness deficit related to math fact retrieval problems

DeSmedt, B., & Boets, B. (2010). Phonological processing and arithmetic fact retrieval: Evidence from developmental dyslexia. Neuropsychologia, 48(14), 3973-3981.

Abstract

The triple-code model, cognitive neuroimaging and developmental behavioral data suggest a specific association between phonological processing and arithmetic fact retrieval. Accordingly, individuals with deficits in phonological processing, such as individuals with developmental dyslexia, are expected to show difficulties in arithmetic fact retrieval. The present study tested this proposal in 25 adults with developmental dyslexia and 25 matched controls by examining strategy use during single-digit multiplication and subtraction and its associations with phonological processing. Findings revealed that individuals with dyslexia retrieved fewer arithmetic facts from memory and were less efficient in doing so. At the same time, they showed deficits in phonological processing. Phonological processing, particularly phonological awareness, was related to arithmetic fact retrieval. This association was especially prominent in multiplication, indicating that fact retrieval in multiplication rather than subtraction is mediated by phonological processes. These data provide ground for future neuroimaging studies, who should examine the neural overlap between phonological processing and multiplication fact retrieval in the same sample of participants.


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