Global and Local Visual Processing in Rate/Accuracy Subtypes of Dyslexia.

Words are processed in both a global and local manner. Studies on global versus local processing styles in individuals with and without dyslexia are inconclusive. In the present study, we investigated whether distinct patterns of global/local visual processing were associated with more precisely defined dyslexia profiles. Previous studies on dyslexia provide evidence of accuracy- and rate-based subtypes, with impairment in one dimension alongside normal performance in the other. In the current study, three groups of adult readers: rate disability, accuracy disability, typical development, were presented with nonlinguistic global /local congruency task. The results revealed that the rate disability group had deficiencies performing the global task while the accuracy disability group had deficiencies in the local task. These results are discussed in the context of global/local word processing and in relation to dyslexia. Specifically, they suggest that different patterns of global/local processing are observed between different types of dyslexics, and imply that practitioners should modify their treatment based on the specific deficiency.

Examining the double-deficit hypothesis in vowelized-transparent Arabic in a national representative sample of Grades 3 and 4.

We examined the double-deficit hypothesis in Arabic by investigating the reading and cognitive profiles of readers with selective deficits in naming speed, phonological awareness, or both. In a nationally representative sample of 486 children in the third and fourth grades, we identified 171 children with reading difficulties: 20 (12%) were classified as having a phonological deficit, 31 (18%) as having a naming speed deficit, and 41 (24%) as having a double deficit. Differences between the subgroups extended to reading, cognitive, and linguistic processes beyond phonological and naming abilities. Children with a double deficit performed worse than those with a naming speed deficit but similar to those with a phonological deficit. Numerous unconfirmed theories led to an in-depth analysis of the nature of rapid automatized naming and its relation to orthographic processing. Surprisingly, our findings revealed that orthographic processing may be considered a novel and separate core deficit, suggesting a triple deficit in Arabic rather than a double deficit. The findings are discussed in light of the uniqueness and complexity of Arabic orthography and orthographic transparency in the Arabic language.

The Role of Trait Anxiety and Preoccupation With Reading Disabilities of Children and Their Mothers in Predicting Children's Reading Comprehension.

This study investigated the relationship between reading comprehension (RC), trait anxiety, and preoccupation with reading disability (RD) in 88 school children in Grades 3 through 5 and in their mothers. Children's trait anxiety had a significant direct negative relationship with RC and also mediated the association between preoccupation with RD and RC. Mothers' preoccupation with their children's RDs had a direct negative association with their children's RC. This association was also mediated through children's trait anxiety. No association was found between mothers' trait anxiety and children's RC. In a final model, RC was explained significantly by children's word reading fluency and trait anxiety as well as by their mothers' preoccupation with their children's RDs. This study extends our understanding of multicomponential models of RC by shedding light on the significant role played by anxiety- and preoccupation-related factors involving both children with RDs and their mothers.

Friendship predictors of global self-worth and domain-specific self-concepts in university students with and without learning disability.

This study investigated the association among friendship, global self-worth, and domain-specific self-concepts in 102 university students with and without learning disabilities (LD). Students with LD reported lower global self-worth and academic self-concept than students without LD, and this difference was greater for women. Students with LD also reported that they had more stable friendships than students without LD. Students with LD were more likely to have higher global self-worth and self-perceptions of social acceptance if they had stable friendships and had relationships where they communicated spontaneously and frankly. None of the friendship variables predicted academic self-concept. Thus, having stable and intimate friendships is a protective factor in relation to global self-worth and social self-concept in university students with LD.

Rate- and accuracy-disabled subtype profiles among adults with dyslexia in the Hebrew orthography.

This study examined a subtyping scheme rooted in the dissociation between reading rate and accuracy in an exceptionally large sample of adult readers with dyslexia using a wide variety of behavioral and event-related potential (ERP) measures. Stage 1 was a behavioral study, in which basic reading skill, reading comprehension, linguistic and cognitive tasks were administered to 661 learning-disabled university students (n = 382) and their non-learning-disabled peers (n = 279). Based on a word reading measure, accuracy-disabled and rate-disabled subgroups were identified, as was a subgroup with deficits in both rate and accuracy. The results support the persistence of a rate versus accuracy dissociation into adulthood. Accuracy disability was related to a broad range of deficits affecting phonological, orthographic, and morphological processing, verbal memory, attention, and reading comprehension. Rate disability appeared to be associated with slower processing of printed material, alongside largely intact functioning resembling those of skilled readers. In stage 2, electroencephalogram (EEG)-ERP measurements were obtained from 140 participants recruited from the larger sample. Activation in visual association cortex, indicated by the N170 amplitude, was found to be lower for accuracy-disabled than skilled readers, and comparable between rate-disabled and skilled readers. The lowest amplitude was found in the double-deficit subgroup. The findings support the existence of distinctive reading disability profiles, based on selective deficits in reading rate versus accuracy and associated with different basic reading, linguistic, and cognitive skills as well as electrophysiological responses.

Subtypes of reading disability in a shallow orthography: a double dissociation between accuracy-disabled and rate-disabled readers of Hebrew.

Whereas most English language sub-typing schemes for dyslexia (e.g., Castles & Coltheart, 1993) have focused on reading accuracy for words varying in regularity, such an approach may have limited utility for reading disability sub-typing beyond English in which fluency rather than accuracy is the key discriminator of developmental and individual differences in reading ability. The present study investigated the viability of an accuracy/fluency-based typology in a regular orthography, pointed Hebrew. We sought evidence of true or "hard" accuracy/rate subtypes in the strict (double dissociation) sense of selective impairment on only one dimension in the presence of normal levels of performance on the other dimension. In a nationally representative sample of fourth graders, we were able to identify a specific accuracy-disabled sub-group as well as an equally specific rate-disabled subgroup. Validating this subdivision, we show that the nature of reading performance in these subgroups and their converging cognitive/linguistic profiles are unique and distinctive on variables other than the measures used to define them. While the rate-specific disability appeared to reflect a general deficit in speed of processing affecting reading rate, and rapid automatized naming of print-related material, the accuracy-only disability subgroup displayed selective deficits in phonological awareness and morphological knowledge. Biosocial, demographic, and instructional factors, furthermore, did not explain the sub-group differences. It appears that both these subtypes are equally prevalent each counting close to 10% of the population.

Knowledge about and preoccupation with reading disabilities: a delicate balance.

This study investigated the extent to which children's knowledge about reading disabilities, preoccupation with their own reading disability, and anxiety predicted reading comprehension in fifth and sixth grade children with reading disabilities (N=85). Participants provided rich and accurate information about reading disabilities and the academic and emotional implications of having a reading disability. Children's knowledge about the characteristics of reading disabilities was positively associated with reading comprehension, and preoccupation with their own disability was negatively associated with reading comprehension. Girls reported higher levels of preoccupation and anxiety than boys did. In addition to gender, children's reading comprehension, trait anxiety, and perceptions of their mothers' worry about their reading disabilities predicted their preoccupation with their own disability. Children with the most adaptive profile in terms of reading comprehension and anxiety were those who had high levels of knowledge and low levels of preoccupation with their disability.