Gender ratio and cognitive profiles in dyslexia: a cross-national study

The purpose of this study was to analyze possible gender-related differences in the prevalence of dyslexia. A cross-national comparison of Spain and Guatemala was conducted. Both countries speak the same language but have a different standard of living and educational level. A second purpose of this study was to analyze the cognitive profile of Guatemalan and Spanish males and females children with dyslexia. The log-linear analysis indicated that the number of dyslexics detected was different across the countries but there were no differences as a function of gender. Similarly, there were no significant or meaningful differences between dyslexic males and females in the cognitive processes involved in reading. Therefore, gender differences do not appear to be characteristic of developmental dyslexia.     

Gender differences in the severity of adult familial dyslexia

Thirty seven adults with a three generation family history of dyslexia and a strong personal history of reading/spelling problems were administered a psychoeducational battery to confirm the diagnosis of dyslexia. Males were not disproportionately represented in the dyslexic sample although they exhibited a more severe profile of reading impairment relative to females. Severity of dyslexia is discussed as a possible mechanism of the reported higher prevalence of dyslexia among males.     

Temporal processing in dyslexia

The temporal processing capabilities of 15 children with dyslexia versus 15 age-matched and 15 reading-matched controls in a word identification task were examined. The hypothesis underlying the present experiment was that word recognition would be inferior in children with dyslexia, relative to controls, when the task demanded the temporal integration (sequencing) of two-syllable words. Such a hypothesis must predict that one-syllable word recognition does not distinguish between these two populations and that these effects cannot be accounted for in terms of eye movement differences. To test this hypothesis, one- and two-syllable words displayed for 100, 300, and 3,000 msec were required to be identified. The results yielded evidence of decreased accuracy of word identification by the children with dyslexia in the two-syllable, 300-msec condition, as predicted. A second experiment was unable to uncover any differences in eye movement behaviors that could account for the effects observed in the first experiment. The results are discussed in terms of potential sequential processing deficits in individuals with dyslexia.     

Object-naming deficits in developmental dyslexia

This paper reports two experiments which focus on the object naming deficits of dyslexic readers. In Experiment 1, dyslexic and normal readers were asked to name objects depicted by pictures or following their spoken definition. Ten-year-old dyslexics named fewer objects correctly than other children of a similar age, performing only as well as a younger group of 8-year-old normal readers. This was true irrespective of the modality through which they were tested. In terms of naming latency, however, they were similar to comparison groups. In Experiment 2, nine-year-old dyslexic and normal readers performed as well as each other in a receptive vocabulary test in which pictures had to be matched to spoken words. However, once again, on a picture naming test, the dyslexics did less well than controls. We argue that dyslexic children are subject to verbal naming difficulties which cannot be accounted for by generally low levels of vocabulary knowledge. Their problems are attributable not to difficulties in semantic representation but to difficulties with the lexical-phonological representation of spoken words they know. We propose that, in turn, these difficulties are related to their memory and reading problems.     

Morphological awareness in developmental dyslexia

This study examines morphological awareness in developmental dyslexia. While the poor phonological awareness of dyslexic children has been related to their difficulty in handling the alphabetical principle, less is known about their morphological awareness, which also plays an important part in reading development. The aim of this study was to analyze in more detail the implications of the phonological impairments of dyslexics in dealing with larger units of language such as morphemes. First, the performance of dyslexic children in a series of morphological tasks was compared with the performance of children matched on reading-level and chronological age. In all the tasks, the dyslexic group performed below the chronological age control group, suggesting that morphological awareness cannot be developed entirely independently of reading experience and/or phonological skills. Comparisons with the reading-age control group indicated that, while the dyslexic children were poorer in the morphemic segmentation tasks, they performed normally for their reading level in the sentence completion tasks. Furthermore, they produced more derived words in the production task. This suggests that phonological impairments prevent the explicit segmentation of affixes while allowing the development of productive morphological knowledge. A second study compared dyslexic subgroups defined by their degree of phonological impairment. Our results suggest that dyslexics develop a certain type of morphological knowledge, which they use as a compensatory reading strategy.     

Clock drawing in developmental dyslexia

Although developmental dyslexia is often defined as a language-based reading impairment not attributable to low intelligence or educational or socioeconomic limitations, the behavioral manifestations of dyslexia are not restricted to the realm of language. Functional brain imaging studies have shed light on physiological differences associated with poor reading both inside and outside the classical language areas of the brain. Concurrently, clinically useful tests that elicit these nonlinguistic deficits are few. Specifically, the integrity of the dorsal visual pathway, which predominantly projects to the parietal cortex, remains underinvestigated, lacking easily administered tests. Here we present the Clock Drawing Test (CDT), used to test the visuoconstructive ability of children with and without dyslexia and garden-variety poor readers. Compared to typically reading children, many children with dyslexia and some garden-variety poor readers showed significant left neglect, as measured by the distribution of figures drawn on the left clock face. In the poor readers with dyslexia, we observed spatial construction deficits like those of patients with acquired right-hemisphere lesions. The results suggest that in some children with dyslexia, right-hemisphere dysfunction may compound the phonological processing deficits attributed to the left hemisphere. The CDT provides an easy opportunity to assess skills known to be associated with right-hemisphere parietal function. This test can be easily administered to children for both clinical and research purposes.     

Dyscalculia and dyslexia

Conclusion It is our hope that more practitioners in the field of learning disabilities will include the diagnosis and treatment of dyscalculia as they work with children and older individuals. Although there is much more to be explored, we believe that our clinical experience indicates that information-processing deficits may be a contributory factor in the disability and thus warrant further investigation. Furthermore, we believe that insights gained in the treatment of specific language disability may be fruitfully applied in the treatment of dyscalculia. This paper is a condensed version of a presentation at the 29th Annual Conference of The Orton Society, November 1978, at Minneapolis, Minnesota.     

Living with dyslexia

This study facilitates the use of Curriculum-Based Measurement (CBM) to investigate the effect of short vowels on oral reading fluency (ORF) and silent reading comprehension in Arabic orthography. A total sample of 131 fifth-grade students (89 skilled readers and 42 poor readers) participated in the study. Two kinds of CBM probes were administered: CBM ORF and CBM Maze. Nine texts of each kind were presented in three reading conditions: fully vowelized, partially vowelized and unvowelized. Results indicated that CBM ORF and CBM Maze tests distinguished between skilled and poor readers in all vowelization conditions. In addition, vowels were a good facilitator of oral reading fluency and silent reading comprehension for both types of readers. Implications and suggestions for future research are discussed in this study as well.     

Prevalence,gender ratio and gender differences in reading‐related cognitive abilities among Chinese children with dyslexia in Hong Kong

Based on the data of the normative study of the Hong Kong test of specific learning difficulties in reading and writing, and the Test of visual‐perceptual skills (non‐motor)—Revised, 99 children aged between 6 and 10½ years were identified as children with dyslexia out of the normative sample of 690 children. By excluding 12 children known to score below average in IQ, 87 children, including 20 children not tested for IQ, could be regarded as children with dyslexia, yielding a prevalence rate of 12.6% and a boy:girl gender ratio of 1.6 to 1. The figures would become 9.7% and 2.0 to 1 if the 20 children were omitted from computation. However, gender imbalance could not be readily explained by gender differences in reading‐related cognitive abilities, as there were only minor and subtle differences. Regression analyses to evaluate the relative contribution of different cognitive abilities to reading and writing suggested that orthographic knowledge and naming speed were most important among children with dyslexia. Implications of the findings and the need for early intervention are discussed.     

Specificity and parameters in defining dyslexia

Conclusion The concern for specificity in definition on the part of researchers and policy makers is understandable. Those on the line, confronted by children who need to be helped, and those who have a working familiarity with the complexity of the reading process, and of the reading disability syndrome, may share my reservations about this specificity: that in defining reading disability strictly in terms of a significant deviation from IQ restrictions are imposed that may obscure important aspects and interactions in the clinical picture. I am in favor of careful selection of samples and of persistence in the search for better defining parameters. Until we have them it may be desirable to operate within looser guidelines and to base treatment on a careful evaluation of linguistic, cognitive, emotional and cultural functioning, when the aim is to teach individual children. If Alexander Pope’s admonition (in “An Essay on Criticism,” Part I) is kept in mind we should not go too far astray: First follow Nature, and your judgment frame By her just standard... This paper was presented at the pre-conference symposium on the definition of dyslexia at the 29th Annual Conference of the Orton Society, Minneapolis, November 1978.     

Reading in French-speaking adults with dyslexia

This study investigated the reading and reading-related skills of 15 French-speaking adults with dyslexia, whose performance was compared with that of chronological-age controls (CA) and reading-level controls (RL). Experiment 1 assessed the efficiency of their phonological reading-related skills (phonemic awareness, phonological short-term memory, and rapid automatic naming (RAN)) and experiment 2 assessed the efficiency of their lexical and sublexical (or phonological) reading procedures (reading aloud of pseudowords and irregular words of different lengths). Experiment 1 revealed that adults with dyslexia exhibited lower phonological reading-related skills than CAs only, and were better than RL controls on the RAN. In experiment 2, as compared with RL controls, only a deficit in the sublexical reading procedure was observed. The results of the second experiment replicated observations from English-language studies but not those of the first experiment. Several hypotheses are discussed to account for these results, including one related to the transparency of orthographic systems.