Double-Deficit Hypothesis in a Clinical Sample: Extension Beyond Reading

Investigating the double-deficit hypothesis of developmental dyslexia in an orthography of intermediate depth

The present study aimed to investigate the double-deficit hypothesis (DDH) in an orthography of intermediate depth. Eighty-five European Portuguese-speaking children with developmental dyslexia, aged 7 to 12, were tested on measures of phonological awareness (PA), naming speed (NS), reading, and spelling. The results indicated that PA and NS were not significantly correlated, and that NS predicts reading fluency (but not reading accuracy and spelling) beyond what is accounted for by PA. Although the majority of the children with developmental dyslexia have double deficit (62.4%), some children have a single phonological deficit (24.7%) or a single NS deficit (8.2%). Children with a double deficit were not more impaired in reading fluency, reading accuracy, and spelling than both single-deficit subtypes. In conclusion, the findings of the present study are partially consistent with the DDH and provide evidence for the multifactorial model of developmental dyslexia. Implications of the DDH for an orthography of intermediate depth are emphasized.

The effect of phonological awareness on rapid automatized naming

Background: Phonological awareness (PA) is a fundamental predictor of reading disability. However, researches on reading have indicated that PA assessment alone is not sufficient to prevent reading problems. Rapid automatized naming (RAN) has been suggested as another influential factor in reading deficits independent of PA. This study investigated the impact of phonological awareness on rapid automatized naming.

Methods: This was a randomized clinical trial study in which 62 Persian monolingual first graders were recruited from 3 schools using convenience sampling. Inclusion criteria were lack of deficits with sensory-motor skills and knowledge of the Persian alphabets. Measures of PA and RAN were utilized. The participants were randomly assigned into either the intervention or the control group. The intervention group was divided into small groups of 4-6 children who received thirty 40-minute training sessions in PA. T test, Mann-Whitney, and Wilcoxon tests were used for data analysis.

Results: The results revealed that the RAN time was significantly reduced (p≤0.001), with a significant increase in PA scores (p≤0.001). In addition, there was a significant inverse relationship between some of the measures of the phonological awareness subtests and rapid automatized naming (eg, phonemic blending & RAN (numbers): ρ=-0.52 with p≤0.001).

Conclusion: The findings showed that in the initial assessment, PA and RAN had a significant relationship, but RAN could be significantly improved by PA training.

Resolving reading disability-Childhood predictors and adult-age outcomes

We examined frequency of adult-age reading disability (RD) and its childhood predictors among 48 adults (20 to 39 years) with documented childhood RD, and contrasted their cognitive skills, education, and employment with 37 matched controls. Among individuals with childhood RD, more than half had improved in their reading fluency to the level where the set criterion for adult-age RD was not met anymore. More fluent rapid naming, less severe childhood RD, and multiple support providers in childhood together predicted improvement of reading fluency. More fluent naming differentiated the childhood RD participants whose reading fluency had improved by adult-age from those participants whose RD persisted to adult-age. All the individuals with childhood RD performed weaker than the controls in adult-age working memory, processing speed, and verbal skills. Educational level among both RD groups was lower than that among the controls. Unemployment of individuals with persistent adult-age RD (31.6%) was higher than that of individuals with improved adult-age RD (13.8%) or that of the controls (8.1%). According to our findings, rapid naming is one evident factor differentiating individuals with persisted RD from those with ameliorated reading fluency. Also, better adult-age reading fluency has significance for adult-age employment among individuals with childhood RD.

Cracking the Code: The Impact of Orthographic Transparency and Morphological-Syllabic Complexity on Reading and Developmental Dyslexia

Reading is an essential skill in modern societies, yet not all learners necessarily become proficient readers. Theoretical concepts (e.g., the orthographic depth hypothesis; the grain size theory) as well as empirical evidence suggest that certain orthographies are easier to learn than others. The present paper reviews the literature on orthographic transparency, morphological complexity, and syllabic complexity of alphabetic languages. These notions are elaborated to show that differences in reading acquisition reflect fundamental differences in the nature of the phonological recoding and reading strategies developing in response to the specific orthography to be learned. The present paper provides a narrative, cross-linguistic and integrated literature review, thereby contributing to the development of universal reading models and at the same time pointing out the important differences between orthographies at the more detailed level. Our review also yields suggestions to devise language-specific instruction and interventions for the development of the specific reading strategies required by the characteristics of the orthography being acquired.

Innate or Acquired? - Disentangling Number Sense and Early Number Competencies

The clinical profile termed developmental dyscalculia (DD) is a fundamental disability affecting children already prior to arithmetic schooling, but the formal diagnosis is often only made during school years. The manifold associated deficits depend on age, education, developmental stage, and task requirements. Despite a large body of studies, the underlying mechanisms remain dubious. Conflicting findings have stimulated opposing theories, each presenting enough empirical support to remain a possible alternative. A so far unresolved question concerns the debate whether a putative innate number sense is required for successful arithmetic achievement as opposed to a pure reliance on domain-general cognitive factors. Here, we outline that the controversy arises due to ambiguous conceptualizations of the number sense. It is common practice to use early number competence as a proxy for innate magnitude processing, even though it requires knowledge of the number system. Therefore, such findings reflect the degree to which quantity is successfully transferred into symbols rather than informing about quantity representation per se. To solve this issue, we propose a three-factor account and incorporate it into the partly overlapping suggestions in the literature regarding the etiology of different DD profiles. The proposed view on DD is especially beneficial because it is applicable to more complex theories identifying a conglomerate of deficits as underlying cause of DD.

Examining the relationship between rapid automatized naming and arithmetic fluency in Chinese kindergarten children

Rapid automatized naming (RAN) has been found to predict mathematics. However, the nature of their relationship remains unclear. Thus, the purpose of this study was twofold: (a) to examine how RAN (numeric and non-numeric) predicts a subdomain of mathematics (arithmetic fluency) and (b) to examine what processing skills may account for the RAN-arithmetic fluency relationship. A total of 160 third-year kindergarten Chinese children (83 boys and 77 girls, mean age=5.11years) were assessed on RAN (colors, objects, digits, and dice), nonverbal IQ, visual-verbal paired associate learning, phonological awareness, short-term memory, speed of processing, approximate number system acuity, and arithmetic fluency (addition and subtraction). The results indicated first that RAN was a significant correlate of arithmetic fluency and the correlations did not vary as a function of type of RAN or arithmetic fluency tasks. In addition, RAN continued to predict addition and subtraction fluency even after controlling for all other processing skills. Taken together, these findings challenge the existing theoretical accounts of the RAN-arithmetic fluency relationship and suggest that, similar to reading fluency, multiple processes underlie the RAN-arithmetic fluency relationship.