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1.
The prevalence of phonological and surface dyslexia subtypes among Swedish university students with dyslexia (n = 40) was examined using both the regression method, developed by Castles and Coltheart, and latent profile analysis. When an academic‐level control group was used as a reference group in a regression, eight students with phonological dyslexia and 15 students with surface dyslexia were identified. In contrast, 17 students with phonological dyslexia and two students with surface dyslexia were identified when the subtypes were defined by reference to a reading‐level control group, indicating a deviant profile among the students with phonological dyslexia and delayed development among those with surface dyslexia. The latent profile analysis was based on five phonological and four orthographic tasks. Seven profiles were obtained, of which none exhibited deficits in orthographic but not in phonological skills or vice versa. Thus, the analysis further supported the phonological deficit hypothesis of dyslexia. 相似文献
2.
The double-deficit hypothesis of developmental dyslexia proposes that deficits in phonological processing and naming speed represent independent sources of dysfunction in dyslexia. The present article is a review of the evidence for the double-deficit hypothesis, including a discussion of recent findings related to the hypothesis. Studies in this area have been characterized by variability in methodology--how dyslexia is defined and identified, and how dyslexia subtypes are classified. Such variability sets limitations on the extent to which conclusions may be drawn with respect to the double-deficit hypothesis. Furthermore, the literature is complicated by the persistent finding that measures of phonological processing and naming speed are significantly correlated, resulting in a statistical artifact that makes it difficult to disentangle the influence of naming speed from that of phonological processing. Longitudinal and intervention studies of the double-deficit hypothesis are needed to accumulate evidence that investigates a naming speed deficit that is independent of a phonological deficit for readers with dyslexia. The existing evidence does not support a persistent core deficit in naming speed for readers with dyslexia. 相似文献
3.
4.
The spelling errors of third graders who fit phonological andsurface profiles of developmental dyslexia were analyzed, alongwith the errors of younger (reading level matched) andchronologically age matched non-dyslexic comparison groups. InStudy 1, errors were analyzed as phonologically constrained,unconstrained, or inaccurate and as either orthographicallyacceptable or unacceptable. Study 2 extended the errorclassification system to nonword spellings. The main finding wasthat different types of dyslexics produced different types oferrors. Both studies found that children produced spelling errorsconsistent with their type of dyslexia. The phonological groupshowed poor knowledge of phoneme-grapheme correspondences,consistent with the existence of a phonological deficit. Thesurface group's spelling error profile differed from thephonological group and closely resembled the younger normalcomparison group. This pattern is consistent with other evidencethat surface dyslexia represents a general delay in acquiringliteracy skills. The studies provide converging evidence, from aspelling task, that developmental dyslexia is a non-homogeneouscategory consisting of at least two major subtypes with distinctetiologies and behavioral sequelae. 相似文献
5.
This paper consists of three studies. The first study aimed to identify sub-types of students with learning disabilities in reading. Based on the dual-route model of reading, words may be read using either a lexical (words are recognized as wholes) or a sub-lexical (words are recognized through grapheme-phoneme correspondence) procedure. Castles and Coltheart (1993) provided evidence for the existence of these two mechanisms in English reading. They suggested that deficits in one and/or the other mechanism would lead to different patterns of reading disability. Surface dyslexia results from an impairment of the lexical procedure with an intact phonological route to reading. Phonological dyslexia results from a deficit in the grapheme-phoneme transformation mechanism. A higher percentage of surface dyslexia was identified in the present study. The aim of the second study was to analyze reading errors to support the existence of surface and phonological dyslexic patterns in Chinese reading. The results showed that students with surface dyslexic pattern made more phonological errors, whereas students with phonological dyslexic pattern made more semantic errors. These two studies indicate that students with learning disabilities could have different strengths and weaknesses and could have different preferences for recognizing Chinese characters and different responses to instructional methods. The third study was designed to test the effects of different teaching methods and different kinds of Chinese characters on students with learning disabilities. In general, the analytic method was found more effective for students with surface dyslexic pattern and the whole-word method for those with the phonological dyslexic pattern. The findings of this study showed the importance of identifying the strengths of the different sub-types of readers and the need to choose appropriate instructional methods accordingly. 相似文献
6.
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
7.
We report a case study of an acquired dyslexic subject, who on tasks standardly used to assess acquired dyslexia showed no evidence of having any access to sublexical phonological information. However, on a lexical decision task, he showed normal effects of spelling regularity for low-frequency words. Since this effect is typically attributed to the use of sublexical phonological information in word recognition, it appears that sublexical phonological processing is occurring for this subject. The spelling regularity effect is discussed with respect to models of written word recognition and to acquired dyslexia. It is suggested that the reason for the discrepancy in test results may be that the types of explicit tasks previously used in the neuropsychological literature on dyslexia, which require conscious awareness of phonological representations, are not sensitive to implicit processing. 相似文献
8.
Margaret J. Snowling Fiona Duff Alex Petrou Josie Schiffeldrin Alison M. Bailey 《Journal of Research in Reading》2011,34(2):157-170
We report an investigation of the validity of teachers' ratings of children's progress in ‘phonics’ as a screener for dyslexia. Seventy‐three 6‐year‐olds from a whole school population were identified as ‘at risk’ of dyslexia according to teacher judgements of slow progression through phonic phases. Six months later, children's attainments in literacy and phonological skills were compared with those of their typically developing peers matched on age and gender. Teacher assessments of risk were related to individual differences in performance on a standardised test of reading ability. Teacher assessments overestimated ‘risk of dyslexia’, defined as below‐average reading performance. However, teacher judgements, supplemented by tests of phoneme awareness and rapid naming, allowed a sensitive and specific identification of children who subsequently experienced reading difficulties. These findings show teachers can identify risk of dyslexia; the accuracy of this process can be improved by administering two tests of phonological skills. 相似文献
9.
This study evaluated the effect of sound-symbol association training on visual and phonological memory in children with a history of dyslexia. Pretests of phonological and visual memory, a sound-symbol training procedure, and phonological and visual memory posttests were administered to children with dyslexia, to children whose dyslexia had been compensated through remedial training, and to age- and reading level-matched comparison groups. Deficits in visual and phonological memory and memory for sound-symbol associations were demonstrated in the dyslexia group. For children with dyslexia and children whose dyslexia had been remediated, the sound-symbol training scores were significantly associated with word and pseudoword reading scores and were significantly lower than those of the comparison groups. Children with dyslexia and children whose dyslexia had been compensated showed significantly less facilitation of phonological memory following the training than did typical readers. Skilled readers showed some reduction in accuracy of visual memory following the training, which may be the result of interference of verbalization with a predominantly visual task. A parallel decrease was not observed in the children with dyslexia, possibly because these children did not use the verbal cues. Children with dyslexia and children whose dyslexia had been compensated seemed to have difficulty encoding the novel sounds in memory. As a result, they derived less phonological memory advantage and less visual memory interference from the training than did typical readers. Children in the compensated dyslexia group scored lower on sound-symbol training than their age peers. In other respects, the scores of these children were equivalent to those of the typically reading comparison groups. Children in the compensated dyslexia group exhibited higher phonological rehearsal, iconic memory, and associative memory scores than children in the dyslexia group. Implications for the remediation of dyslexia are discussed. 相似文献
10.
Lee LW 《Annals of dyslexia》2008,58(1):37-57
Malay is an alphabetic language with transparent orthography. A Malay reading-related assessment battery which was conceptualised based on the International Dyslexia Association definition of dyslexia was developed and validated for the purpose of dyslexia assessment. The battery consisted of ten tests: Letter Naming, Word Reading, Non-word Reading, Spelling, Passage Reading, Reading Comprehension, Listening Comprehension, Elision, Rapid Letter Naming and Digit Span. Content validity was established by expert judgment. Concurrent validity was obtained using the schools' language tests as criterion. Evidence of predictive and construct validity was obtained through regression analyses and factor analyses. Phonological awareness was the most significant predictor of word-level literacy skills in Malay, with rapid naming making independent secondary contributions. Decoding and listening comprehension made separate contributions to reading comprehension, with decoding as the more prominent predictor. Factor analysis revealed four factors: phonological decoding, phonological naming, comprehension and verbal short-term memory. In conclusion, despite differences in orthography, there are striking similarities in the theoretical constructs of reading-related tasks in Malay and in English. 相似文献
11.
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.
相似文献12.
Franklin R. Manis Mark S. Seidenberg Lynne Stallings Marc Joanisse Caroline Bailey Laurie Freedman Suzanne Curtin Patricia Keating 《Annals of dyslexia》1999,49(1):105-134
There is a consensus that dyslexia is on a continuum with normal reading skill and that dyslexics fall at the low end of the
normal range in phonological skills. However, there is still substantial variability in phonological skill among dyslexic
children. Recent studies have focused on the high end of the continuum of phonological skills in dyslexics, identifying a
“surface” dyslexic, or “delayed” profile in which phonological skills are not out of line with other aspects of word recognition.
The present study extended this work to a longitudinal context, and explored differences among subgroups of dyslexics on a
battery of component reading skills. Third grade dyslexics (n=72) were classified into two subgroups, phonological dyslexics and delayed dyslexics, based on comparisons to younger normal
readers at the same reading level (RL group). The children were tested at two points (in third and fourth grade). The results
revealed that the classification of dyslexics produced reliable, stable, and valid groups. About 82 percent of the children
remained in the same subgroup category when retested a year later. Phonological dyslexics were lower in phoneme awareness
and expressive language. Delayed dyslexics tended to be slower at processing printed letters and words but not at rapid automatic
naming of letters, and relied more heavily on phonological recoding in reading for meaning than did phonological dyslexics.
A subset of the delayed dyslexics with the traditional “surface dyslexic” pattern (relatively high pseudoword and low exception
word reading) was also identified. The surface subgroup resembled the RL group on most measures and was not very stable over
one year. The results are discussed in light of current models of dyslexia and recent subgrouping schemes, including the Double-Deficit
Hypothesis. 相似文献
13.
Persistence of phonological processing deficits in college students with dyslexia who have age-appropriate reading skills 总被引：7，自引：0，他引：7
This study investigated the phonological processing skills of university students with dyslexia. Fifty-nine students participated in this study: 28 with reading disabilities based on recent psychological assessments and a history of early and persistent reading problems; and 31 controls. The two groups did not differ on estimates of verbal and nonverbal abilities. The dyslexia group performed significantly less well on standardized measures of reading and spelling. However, the dyslexia group scores on these measures fell within the average range. The main dependent variables were subsumed under three areas of phonological processing: phonological awareness, phonological recoding in lexical access, and phonological recoding in working memory. The control group performed significantly better on all phonological processing measures, particularly those measures involving accuracy and response times. Despite age-appropriate performances on standardized reading and spelling measures, phonological processing deficits persisted in the dyslexia group. These findings support the causal role of phonological awareness in the acquisition of reading skills and indicate that differences in phonological processing skills are still evident in a sample of university students with dyslexia compared a group matched on age and education. 相似文献
14.
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
15.
In addition to an intrinsic difficulty in reading and spelling, one of the defining characteristics of dyslexia is an enduring and pervasive difficulty in phonological coding, such that dyslexic readers find it particularly challenging to process and manipulate the constituent sounds of a language. Coexistent with this finding is the evidence that some dyslexic readers also demonstrate subtle sensory coding problems in the visual and auditory domains. Few theories have been proposed to unite these different findings within a coherent model of reading. Here the evidence for visual, auditory and phonological coding problems in dyslexia is briefly reviewed, and a hypothesis is proposed for how adequate early sensory coding may be intrinsic to phonological awareness and subsequent reading ability. In this hypothesis, a cortical network is assumed that incorporates the visual, auditory and phonological skills of reading. The visual sub‐component of the network is mediated by the dorsal visual pathway, which is responsible for the accurate spatial encoding of letters, words and text. The auditory component of the network in pre‐readers is intrinsic to the development of phonological sensitivity, and then grapheme‐phoneme assimilation as reading skills develop. In this hypothesis, some of the symptoms of dyslexia may result from subtle problems in the encoding of both visual and auditory information and their role in maintaining the synchronicity of the reading network. 相似文献
16.
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
17.
John Everatt Ian Smythe Dina Ocampo Eva Gyarmathy 《Journal of Research in Reading》2004,27(2):141-151
This paper focused on the assessment of phonological skills amongst children with developmental dyslexia. Findings from assessments of English and Hungarian monolingual children with and without literacy deficits and bilingual Filipino children with and without literacy deficits in English indicated that performance on phonological‐based tasks often used in dyslexia assessment batteries was influenced by the language background. Monolingual English children with poor literacy skills showed characteristic deficits in most areas of phonological ability, whereas Hungarian counterparts showed little evidence of such difficulties. Bilingual Filipino children with poor English literacy skills showed equivalent profiles to their monolingual counterparts only when assessments in both English and Filipino were considered. The paper discusses difficulties of generalising assessment procedures from one language context to another. 相似文献
18.
Phonological difficulties characterize children with developmental dyslexia across languages, but whether impaired auditory processing underlies these phonological difficulties is debated. Here the causal question is addressed by exploring whether individual differences in sensory processing predict the development of phonological awareness in 86 English-speaking lower- and middle-class children aged 8 years in 2005 who had dyslexia, or were age-matched typically developing children, some with exceptional reading/high IQ. The predictive relations between auditory processing and phonological development are robust for this sample even when phonological awareness at Time 1 (the autoregressor) is controlled. High reading/IQ does not much impact these relations. The data suggest that basic sensory abilities are significant longitudinal predictors of growth in phonological awareness in children. 相似文献
19.
It is now thought that the cerebellum is involved in the acquisition of “language dexterity” in addition to its established
role in motor skill acquisition and execution. Mild cerebellar impairment, therefore, provides a possible explanation of a
range of problems shown by children with dyslexia. The authors have established suggestive evidence in support of this hypothesis
in tests of balance and of time estimation. In a further test of the hypothesis, a battery of clinical tests for cerebellar
impairment, including tests of muscle tone and of coordination, was administered to matched groups of children with dyslexia
and control children aged 10, 14, and 18 years (55 subjects in all). The children with dyslexia showed highly significant
impairments on all the cerebellar tests, and significant impairment compared even with reading age controls on 11 of the 14
tasks. Deficits on the majority of tests were among the largest found in our research program. The findings, therefore, provide
further intriguing evidence of cerebellar impairment in dyslexia. We speculate that the well-established phonological deficits
in dyslexia may arise initially from inefficient articulatory control attributable to cerebellar impairment. 相似文献
20.
L S Siegel 《Journal of learning disabilities》1992,25(10):618-629
The purpose of this study was to determine whether children with dyslexia, that is, children whose reading levels were significantly lower than would be predicted by their IQ scores, constituted a distinctive group when compared with poor readers, that is, children whose reading scores were consistent with their IQ scores. The performance of children with dyslexia, poor readers, and normally achieving readers was compared on a variety of reading, spelling, phonological processing, language, and memory tasks. Although the children with dyslexia had significantly higher IQ scores than the poor readers, these two groups did not differ in their performance on reading, spelling, phonological processing, or most of the language and memory tasks. In all cases, the performance of both reading disabled groups was significantly below that of nondisabled readers. The findings were similar whether absolute difference or regression scores were used. Reading disabled children, whether or not their reading is significantly below the level predicted by their IQ scores, experience significant problems in phonological processing, short-term and working memory, and syntactic awareness. On the basis of these data, there does not seem to be a need to differentiate between individuals with dyslexia and poor readers. Both of these groups are reading disabled and have deficits in phonological processing, verbal memory, and syntactic awareness. 相似文献