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1.
Previous research suggests that individuals with developmental dyslexia perform below typical readers on non-linguistic cognitive tasks involving the learning and encoding of statistical-sequential patterns. However, the neural mechanisms underlying such a deficit have not been well examined. The aim of the present study was to investigate the event-related potential (ERP) correlates of sequence processing in a sample of children diagnosed with dyslexia using a non-linguistic visual statistical learning paradigm. Whereas the response time data suggested that both typical and atypical readers learned the statistical patterns embedded in the task, the ERP data suggested otherwise. Specifically, ERPs of the typically developing children (n?=?12) showed a P300-like response indicative of learning, whereas the children diagnosed with a reading disorder (n?=?8) showed no such ERP effects. These results may be due to intact implicit motor learning in the children with dyslexia but delayed attention-dependent predictive processing. These findings are consistent with other evidence suggesting that differences in statistical learning ability might underlie some of the reading deficits observed in developmental dyslexia. 相似文献
2.
Valdois Sylviane Bosse Marie-Line Ans B. Carbonnel S. Zorman Michel David D. Pellat Jacques 《Reading and writing》2003,16(6):541-572
The present study describes two Frenchteenagers with developmental reading andwriting impairments whose performance wascompared to that of chronological age andreading age matched non-dyslexic participants.Laurent conforms to the pattern of phonologicaldyslexia: he exhibits a poor performance inpseudo-word reading and spelling, producesphonologically inaccurate misspellings butreads most exception words accurately. Nicolas,in contrast, is poor in reading and spelling ofexception words but is quite good atpseudo-word spelling, suggesting that hesuffers from surface dyslexia and dysgraphia.The two participants were submitted to anextensive battery of metaphonological tasks andto two visual attentional tasks. Laurentdemonstrated poor phonemic awareness skills butgood visual processing abilities, while Nicolasshowed the reverse pattern with severedifficulties in the visual attentional tasksbut good phonemic awareness. The presentresults suggest that a visual attentionaldisorder might be found to be associated withthe pattern of developmental surface dyslexia.The present findings further show thatphonological and visual processing deficits candissociate in developmental dyslexia. 相似文献
3.
The development of reading skills may depend to a certain extent on the development of basic visual perception. The magnocellular
theory of developmental dyslexia assumes that deficits in the magnocellular pathway, indicated by less sensitivity in perceiving
dynamic sensory stimuli, are responsible for a proportion of reading difficulties experienced by dyslexics. Using a task that
measures coherent motion detection threshold, this study examined the relationship between dynamic visual perception and reading
development in Chinese children. Experiment 1 compared the performance of 27 dyslexics and their age- and IQ-matched controls in the coherent motion detection task and
in a static pattern perception task. Results showed that only in the former task did the dyslexics have a significantly higher
threshold than the controls, suggesting that Chinese dyslexics, like some of their Western counterparts, may have deficits
in magnocellular pathway. Experiment 2 examined whether dynamic visual processing affects specific cognitive processes in reading. One hundred fifth-grade children
were tested on visual perception and reading-related tasks. Regression analyses found that the motion detection threshold
accounted for 11% and 12%, respectively, variance in the speed of orthographic similarity judgment and in the accuracy of
picture naming after IQ and vocabulary size were controlled. The static pattern detection threshold could not account for
any variance. It is concluded that reading development in Chinese depends to a certain extent on the development of dynamic
visual perception and its underlying neural pathway and that the impact of visual development can be specifically related
to orthographic processing in reading Chinese. 相似文献
4.
Until recently, many thought developmental dyslexia was a behavioral disorder that primarily affected reading. In fact, it
is a partly heritable condition, the clinical manifestations of which are extremely complex including deficits in reading,
working memory, sensorimotor coordination, and early sensory processing. Even though extensive research has characterized
these behavioral abnormalities carefully, the biological mechanisms of the clinical manifestations still are poorly understood.
Recent research into both the nature of the structural and functional abnormalities in developmental dyslexia and the functional
neuroanatomy of reading have rapidly advanced our understanding of the localization of the processes responsible for the signs
and symptoms of dyslexia. This paper reviews recent evidence supporting a biological basis for developmental dyslexia.
This article was made possible by grant NICHD HD36461 from The Charles A. Dana Foundation and The International Dyslexia Association. 相似文献
5.
Research demonstrates that phonological skills provide the basis of reading acquisition and are a primary processing deficit in dyslexia. This consensus has led to the development of effective methods of reading intervention. However, a single phonological deficit is not sufficient to account for the heterogeneity of individuals with dyslexia, and recent research provides evidence that supports a multiple-deficit model of reading disorders. Two studies are presented that investigate (1) the prevalence of phonological and cognitive processing deficit profiles in children with significant reading disability and (2) the effects of those same phonological and cognitive processing skills on reading development in a sample of children that received treatment for dyslexia. The results are discussed in the context of implications for identification and an intervention approach that accommodates multiple deficits within a comprehensive skills-based reading program. 相似文献
6.
The present study evaluated the idea that the hemisphere-specific cognitive demands of reading and writing may induce task-specific maladaptive patterns of language lateralization in children with dyslexia. Situation-specific lateralization was examined in a repeated measures design under three dichotic listening conditions: baseline, concurrent reading, and concurrent writing. Twelve males with phonological dyslexia, 8 to 12 years old, were compared to 12 age-matched and 12 younger reading-matched good readers. Lateralization patterns were examined for condition-specific relationships to pseudoword decoding, word recognition, reading comprehension, spelling, and arithmetic. The results show that dyslexia is not related to incomplete lateralization or to a failure to inhibit verbal processing in the right hemisphere during reading and writing. Reading increased the lateralization of the children with dyslexia, which had a negative relation to arithmetic; writing caused a decrease in lateralization, which was linked specifically to deficits in phonological decoding and visual word recognition. The results suggest that children with dyslexia suffer from a selective linguistic vulnerability to left-hemisphere interference from the idiosyncratic attentional and processing demands of particular school tasks. Dyslexia is a much more dynamic and environmentally sensitive disorder than previously thought. 相似文献
7.
The visual deficit hypothesis of development dyslexia has largely been abandoned because many of the phenomena that initially motivated it could not be replicated under controlled experimental conditions, while phonological processing deficits were found to provide a better explanation for the replicable phenomena. Nevertheless, many teachers and special educators continue to subscribe to the hypothesis that deficits of visual perception are a major cause of reading failure in dyslexia. As part of a larger family study, we reexamined the questions (1) whether probands and affected relatives in dyslexia families reverse easily confused letters more frequently under experimental conditions than normal readers from the same families, and (2) whether they show unusual facility in reading geometrically transformed text. The findings indicated that young dyslexia students reverse easily confused letters more often than normal readers. Reading group differences of letter reversal were significant in children from 7–10 years but not thereafter; and virtually no subject reversed letters when spelling whole words. Furthermore, dyslexic persons in every age group from 7–60 years actually took longer than normal readers to decode geometrically transformed text; and the time to decode transformed texts increased progressively with age after adolescence in both dyslexic persons and normal readers. Thus, reading group differences in decoding easily confused letters and reading geometrically transformed text do not support the visual deficit hypothesis and probably do not help to clarify the etiology of developmental dyslexia. 相似文献
8.
The question of which cognitive impairments are primarily associated with dyslexia has been a source of continuous debate. This study examined the cognitive profile of Hebrew-speaking compensated adult dyslexics and investigated whether their cognitive abilities accounted for a unique variance in their reading performance. Sixty-nine young adults with and without dyslexia were administered a battery of tests measuring their reading skills and a number of cognitive abilities. The dyslexics were found to exhibit a generally poor cognitive profile, including their attention, visual working memory, naming, visual perception and speed of processing abilities, with the exception of high executive functions skills. Furthermore, naming speed, visual working memory and attention were significantly associated with decoding and fluency measures and predicted group difference after controlling for phonological skills. The findings point to the contribution of cognitive factors to decoding rate and possibly to the ability of utilizing rapid orthographic processes, thus effecting dyslexics’ reading performance. 相似文献
9.
This study was designed to examine whether the phonetic regularity of a language can significantly influence the prevalence and pattern of developmental dyslexia. Demographically matched samples of fifth-grade children in Italy (N = 448) and the United States (N = 1,278) were evaluated to identify children with specific reading disabilities. Reading disabled children with average intelligence were compared to normal controls on a series of neuropsychological tests to evaluate specific cognitive deficits associated with reading disorders in each country. The findings suggested that (a) dyslexia is more prevalent in the United States than in Italy, (b) reading disabilities are strongly associated with disorders of verbal processing in both countries, although some American dyslexics also show visual-motor deficits, and (c) there is a greater dissociation between reading comprehension and decoding in Italian than in English. 相似文献
10.
发展性阅读障碍一直是心理学家关注的重要领域。国外研究者基于认知和生物因素提出了关于发展性阅读障碍的语音缺陷、小脑缺陷、一般性大细胞功能障碍等理论,并考察了患者的眼动特征,提出了有效的诊治方法。汉语发展性阅读障碍研究主要局限在语音和正字法领域,也涉及局部脑区的功能缺陷,但还未从多角度测查其成因,如眼动。该文在理论梳理的基础上,系统探讨了发展性阅读障碍患者的眼动特征及机制。 相似文献
11.
P. G. Aaron 《Annals of dyslexia》1987,37(1):109-125
A controversy whether developmental dyslexia is qualitatively different from other forms of reading disability has existed
among reading specialists for many years. In the present study, the hypothesis that the etiology of dyslexia is different
from that of other forms of reading disability because of differences in the components that malfunction was tested. A number
of studies have shown that the two components that contribute to a large proportion of variance in reading are decoding and
comprehension. It is, therefore, possible that a breakdown of different components could lead to different forms of disabilities.
College students who were poor readers were assigned to two groups on the basis of their IQ. Conforming to the traditional
criterion of dyslexia, those who had an IQ of 95 and above were considered as dyslexic. Those who had an IQ of 85 or below
were placed in the Nonspecific Reading-Disabled group. These two groups of poor readers and a group of normal readers were
administered a large number of reading-related tests. It was found that the two reading-disabled groups differed from each
other in six of the seven areas assessed. There was very little overlap of scores between the two groups in these areas. The
results were interpreted to suggest that poor decoding skill is the etiology of developmental dyslexia and that it differs
from other forms of reading disability which are caused by generalized cognitive deficits. 相似文献
12.
In seven experiments, we investigated whether compensated and uncompensated adults with dyslexia show different patterns of deficits in magnocellular visual processing and in language processing tasks. In four visual tasks, we failed to find evidence of magnocellular deficits in either group. However, both groups of adults with dyslexia showed deficits in component language skills, and the degree of reading impairment predicted the nature and extent of these deficits. Uncompensated readers showed deficits in orthographic and especially phonological coding and awareness and were slower on rapid naming. Compensated readers showed word and nonword performance below controls but better than the uncompensated readers. The compensated group was not significantly less accurate than controls on phonological awareness, nor significantly worse overall on rapid naming. 相似文献
13.
Clock drawing in developmental dyslexia 总被引：2，自引：0，他引：2
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. 相似文献
14.
发展性阅读障碍亚类型的研究 总被引：2，自引：0，他引：2
发展性阅读障碍是关系人类健康和发展的重要课题。多年来研究者试图寻找这个群体中发生困难的真正原因,希望从根本上解决阅读落后问题和消除阅读障碍。但是研究者发现阅读障碍群体内部具有很大的变异性。文章在简介了当今具有代表性的两种流派对阅读障碍原因的解释和相应的研究证据后,着重阐述了阅读障碍的亚类型的发展历史、研究者对亚类型的划分以及不同亚类型在语言技能上、一般感知能力和生理机制方面的差异,并且阐述了亚类型研究对阅读障碍早期预测的作用,为根本消除阅读障碍提供了新的视角。 相似文献
15.
Shay Menashe 《Annals of dyslexia》2018,68(2):145-164
The aim of this study was to gain additional knowledge about the asynchrony phenomenon in developmental dyslexia, especially when spatial selective attention is manipulated. Adults with developmental dyslexia and non-impaired readers underwent two experimental tasks, one including alphabetic stimuli (pre-lexical consonant–vowel syllables) and the other containing non-alphabetic stimuli (pictures and sounds of animals). Participants were instructed to attend to the right or left hemifields and to respond to all stimuli on that hemifield. Behavioral parameters and event-related potentials were recorded. The main finding was that the dyslexic readers demonstrated asynchrony between the auditory and visual modalities when alphabetic stimuli were presented on the right hemifield. These results suggest that intact reading is linked to a synchronized auditory and visual speed of processing even when spatial selective attention is manipulated. The findings of the current study are discussed in terms of asynchrony between modalities as a neurocognitive marker in developmental dyslexia. 相似文献
16.
Electrophysiological correlates of dyslexic subtypes. 总被引：1，自引：0，他引：1
The construct validity of Boder's typology of dyslexia was investigated using quantified EEG. Thirty-nine children, ranging in age from 7-0 to 10-11, were recorded during a contextual reading task and at rest. During reading, children with dyslexia were expected to show increased theta and beta amplitude compared to nondisabled readers. These differences were expected in regions of presumed strength for each subtype as a sign of overengagement in task. Children with phonological deficits (dysphonetic dyslexia) were expected to adopt visuospatial processing strategies (right occipital-parietal activation), those with orthographic deficits (dyseidetic dyslexia) to emphasize phonetic strategies (left temporal-parietal activation). Results supported beta frequency differences in anticipated regions by subtype during the reading task. However, the direction of difference hypothesis was not supported. Decreased amplitudes in both groups with dyslexia compared to normally achieving readers suggest reconceptualization of the theoretical base for the Boder subtyping system. 相似文献
17.
In this study, 123 children with a diagnosis of developmental dyslexia were assigned to different treatment groups, either variations of Bakker's intervention program based on the balance model or a control, a specific reading training group. Thorough cognitive and neuropsychological assessment allowed determination of the subtype of dyslexia according to the balance model and the neuropsychological profile with respect to reading and spelling abilities, verbal memory, and phonemic awareness. Characteristics of hemisphere-specific stimulation were systematically manipulated in an effort to shed light on the bases and mechanisms of reading improvement. It was shown that the effects of treatment vary according to type of dyslexia and that the different intervention programs have differential effects on reading-related neuropsychological functions. Since opposite effects can be produced by the same type of treatment in different dyslexia subtypes, the results of the study suggest that accurate classification of subtype on the base of reading and reading-related variables is advantageous for an optimal planning of the therapy. 相似文献
18.
Most research on dyslexia to date has focused on early childhood, while comparatively little is known about the nature of dyslexia in adolescence. The current study had two objectives. The first was to investigate the relative contributions of several cognitive and linguistic factors to connected‐text oral reading fluency in a sample of adolescents with dyslexia (n = 77). The second was to test the hypothesis that the effect of verbal working memory on connected‐text oral reading fluency is moderated by word‐level skills and/or vocabulary knowledge. The results suggest that many deficits associated with childhood dyslexia remain prominent in adolescence, but the nature of the relationships between key cognitive and linguistic predictors (i.e., word‐level reading, vocabulary, verbal working memory) and reading fluency appear to be different in adolescence. For example, while word‐level skills remain a significant predictor, the strength of the effect is relatively weak. In contrast, the data support an increased role for vocabulary and verbal working memory, including an interaction between these factors. The presence of an interaction can be interpreted as evidence that the influence of verbal working memory on connected‐text oral reading fluency in adolescents with dyslexia depends on individual differences in vocabulary knowledge. These results offer support for the changing nature of dyslexia across development, and suggest that researchers should study dyslexia in adolescents on its own terms, rather than treating it as an extension of reading problems in early childhood. 相似文献
19.
K. Gross-Glenn Bonnie Jallad Loriana Novoa Valerie Helgren-Lempesis H. A. Lubs 《Reading and writing》1990,2(2):161-173
We examined Nonsense-Passage oral reading in adults, using data derived from new and previously published studies (Finucci et al 1976, Gross-Glenn et al 1985). Time-scores and error-frequency data are presented for five samples of non-dyslexic readers with a minimum of a high-school education and no childhood history of dyslexia (N=127). Considerable uniformity is demonstrated across these samples, and reading performance of non-dyslexic individuals contrasts sharply with that observed in four samples of adult familial dyslexics. Both affected and compensated-affected dyslexic subjects read the passages significantly more slowly and with more errors than did nondyslexic readers. Results are discussed in relation to the cognitive and neural processes that may underlie this specific reading difficulty in dyslexics. We have found Nonsense-Passage reading to be especially useful in family studies of inherited dyslexia as a means of quantifying oral reading deficits in adults who have learned to compensate for their children reading difficulties. 相似文献
20.
The present study was designed to examine the question of whether developmental dyslexia in 12-year-old students at the beginning
of secondary education in the Netherlands is confined to problems in the domain of reading and spelling or also is related
to difficulties in other areas. In particular, hypotheses derived from theories on phonological processing, rapid automatized
naming, working memory, and automatization of skills were tested. To overcome the definition and selection problems of many
previous studies, we included in our study all students in the first year of secondary special education in a Dutch school
district. Participants were classified as either dyslexic, garden-variety, or hyperlexic poor readers, according to the degree
of discrepancy between their word recognition and listening comprehension scores. In addition, groups of normal readers were
formed, matching the poor readers in either reading age or chronological age. A large test battery was administered to each
student, including phonological, naming, working memory, speed of processing, and motor tests. The findings indicate that
dyslexia is associated with deficits in (1) phonological recoding, word recognition (both in their native Dutch and in English
as a second language), and spelling skills; and (2) naming speed for letters and digits. Dyslexia was not associated with
deficits in other areas. The results suggest that developmental dyslexia, at the age of 12, might be (or might have become)
a difficulty rather isolated from deficiencies in other cognitive and motor skills. 相似文献