Is orthographic knowledge a strength or a weakness in individuals with dyslexia? Evidence from a meta-analysis

Screening for Dyslexia in University Students: a Standardized Procedure Based on Conditional Inference Trees

OBJECTIVE

The focus of this study is on providing tools to enable researchers and practitioners to screen for dyslexia in adults entering university. The first aim is to validate and provide diagnostic properties for a set of seven tests including a 1-min word reading test, a 2-min pseudoword reading test, a phonemic awareness test, a spelling test, the Alouette reading fluency test, a connected-text reading fluency test, and the self-report Adult Reading History Questionnaire (ARHQ). The second, more general, aim of this study was to devise a standardized and confirmatory procedure for dyslexia screening from a subset of the initial seven tests. We used conditional inference tree analysis, a supervised machine learning approach to identify the most relevant tests, cut-off scores, and optimal order of test administration.

METHOD

A combined sample of 60 university students with dyslexia (clinical validation group) and 65 university students without dyslexia (normative group) provided data to determine the diagnostic properties of these tests including sensitivity, specificity, and cut-off scores.

RESULTS

Results showed that combinations of four tests (ARHQ, text reading fluency, phonemic awareness, pseudoword reading) and their relative conditional cut-off scores optimize powerful discriminatory screening procedures for dyslexia, with an overall classification accuracy of approximately 90%.

CONCLUSIONS

The novel use of the conditional inference tree methodology explored in the present study offered a way of moving toward a more efficient screening battery using only a subset of the seven tests examined. Both clinical and theoretical implications of these findings are discussed.

The Use of Cognitive Tests in the Assessment of Dyslexia

In this literature review, we address the use of cognitive tests, including intelligence tests, in the assessment and diagnosis of dyslexia, from both historic and present-day perspectives. We discuss the role of cognitive tests in the operationalization of the concepts of specificity and unexpectedness, two constructs considered essential to the characterization of dyslexia since the publication of early case reports in the late nineteenth century. We review the advantages and disadvantages of several approaches to specific learning disabilities' identification that are used in schools. We also discuss contemporary debates around the use of standardized cognitive testing in dyslexia evaluations, in particular, the arguments of those who favor an approach to diagnosis based on prior history and the results of a comprehensive evaluation and those who favor an approach based on an individual's response to intervention. We attempt to explain both perspectives by examining clinical observations and research findings. We then provide an argument for how cognitive tests can contribute to an accurate and informed diagnosis of dyslexia.

The multiple-level framework of developmental dyslexia: the long trace from a neurodevelopmental deficit to an impaired cultural technique

Developmental dyslexia is a neurodevelopmental disorder characterized by an unexpected impairment in literacy acquisition leading to specific poor academic achievement and possible secondary symptoms. The multi-level framework of developmental dyslexia considers five levels of a causal pathway on which a given genotype is expressed and hierarchically transmitted from one level to the next under the increasing influence of individual learning-relevant traits and environmental factors moderated by cultural conditions. These levels are the neurobiological, the information processing and the skill level (prerequisites and acquisition of literacy skills), the academic achievement level and the level of secondary effects. Various risk factors are present at each level within the assumed causal pathway and can increase the likelihood of exhibiting developmental dyslexia. Transition from one level to the next is neither unidirectional nor inevitable. This fact has direct implications for prevention and intervention which can mitigate transitions from one level to the next. In this paper, various evidence-based theories and findings regarding deficits at different levels are placed in the proposed framework. In addition, the moderating effect of cultural impact at and between information processing and skill levels are further elaborated based on a review of findings regarding influences of different writing systems and orthographies. These differences impose culture-specific demands for literacy-specific cognitive procedures, influencing both literacy acquisition and the manifestation of developmental dyslexia.

The role of word knowledge in error detection: a challenge to the broken error monitor account of dyslexia

Dyslexic children often fail to correct errors while reading aloud, and dyslexic adolescents and adults exhibit lower amplitudes of the error-related negativity (ERN)-the neural response to errors-than typical readers during silent reading. Past researchers therefore suggested that dyslexia may arise from a faulty error detection mechanism that interferes with orthographic learning and text comprehension. An alternative possibility is that comprehension difficulty in dyslexics is primarily a downstream effect of low-quality lexical representations-that is, poor word knowledge. On this view, the attenuated ERN in dyslexics is a byproduct, rather than a source, of underdeveloped orthographic knowledge. Because the second view implies a direct association of the error response with comprehension skill in populations of all ability levels, the present study evaluates these alternatives through a reanalysis of behavioral and neural data from 31 typical adult readers. If it is true that faulty error processing can manifest as dyslexia, a model in which error monitoring contributes directly to comprehension should outperform a model in which it does not. ERNs recorded during spelling judgments were used as a measure of error detection aptitude in path analyses of reading comprehension. The data were better fit by a model in which error detection aptitude was a consequence of word knowledge than a model in which it contributed directly to comprehension. The findings challenge the notion that comprehension difficulty in dyslexics is attributable to error processing deficits and are consistent with the hypothesis that comprehension difficulty in dyslexics is partially attributable to low-quality word knowledge.

Reading-Related Skills Associated With Acquisition of Chinese as a Second/Foreign Language: A Meta-Analysis

Previous studies have found the effect of cognitive skills (e.g., phonological awareness, morphological awareness, orthographic awareness, and rapid automatized naming) on reading ability, but the role of different reading-related skills in acquisition of Chinese as a second/foreign language (CSL/CFL) remains unexplored. Prior meta-analyses on the relationship between cognitive skills and reading have been conducted primarily in native English-speaking or Mandarin-speaking children. The purpose of the present meta-analysis was to examine the relationship between Chinese reading-related skills and Chinese word reading of CSL/CFL learners. A search of English and Chinese databases yielded 42 effect sizes, comprising 1103 subjects met the criteria for meta-analysis and were included in the final meta-analysis. Results revealed a moderate relationship between phonological awareness (r = 0.41), morphological awareness (r = 0.36), orthographic awareness (r = 0.38), rapid automatized naming (r = -0.32) and Chinese word reading in CSL/CFL learners. In addition, a moderating effect of length of study on the relationship between phonological awareness and Chinese word reading (Q _B = 5.20, p = 0.023): phonological awareness and Chinese word reading correlated more strongly for beginning learners than for advanced learners. These results suggest importance of cognitive factors in the acquisition of Chinese word reading as a second language. Results also shed light on the impact of length of study on the influence from phonological awareness to the sensitive period of phonological learning for CSL/CFL learners.