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1.
Dyslexia and the double deficit hypothesis 总被引：1，自引：4，他引：1
Nathlie A. Badian 《Annals of dyslexia》1997,47(1):69-87
The double deficit hypothesis (Bowers and Wolf 1993) maintains that children with both phonological and naming-speed deficits
will be poorer readers than children with just one or neither of these deficits. In the present study, we drew on this hypothesis
to help understand why some children have a serious reading impairment. In addition, by adding an orthographic factor, we
extended it to a triple deficit hypothesis. Participants were 90 children aged 6 to 10 years. Dyslexic children, whose reading
was low for age and for expected level, garden-variety poor readers, reading-level matched younger children, and low verbal
IQ good readers, were compared. The dyslexic group was significantly lower then the garden-variety poor readers and the low
verbal IQ good readers on most measures, and lower than the younger group on phonological measures. Findings support the double
deficit hypothesis of Bowers and Wolf, and also the triple deficit hypothesis. Most of the poorest readers, nearly all of
whom qualified as dyslexic, had a double or triple deficit in phonological, naming-speed, and orthographic skills. Conclusions
were that dyslexia results from an overload of deficits in skills related to reading, for which the child cannot easily compensate. 相似文献
2.
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
3.
Nathlie A. Badian 《Reading and writing》1994,6(1):45-63
The rationale for the study was that if dyslexic and garden-variety poor readers differ in reading-related cognitive skills, there is justification for believing dyslexia to be a distinct entity. Subjects were 110 children aged 6 to 10 years, divided into groups of dyslexic poor readers varying in verbal IQ, garden-variety poor readers, and good readers. Findings suggest that there are valid grounds for believing that dyslexia is a separate entity from garden-variety poor reading, and that it is found among children at all verbal IQ levels. Poor phonological awareness and nonword reading, in relation to normal readers, were shared by dyslexic and garden-variety poor readers. Deficits unique to dyslexic poor readers were problems in both automatic visual recognition and phonological recoding of graphic stimuli. The study supports the phonological-core variable-difference model of Stanovich (1988) in that both dyslexic and garden-variety poor readers showed phonological processing deficits, but they were more extensive in dyslexics. 相似文献
4.
Despina Paizi Maria De Luca Pierluigi Zoccolotti Cristina Burani 《Journal of Research in Reading》2013,36(3):303-329
Italian developmental dyslexic readers show a striking length effect and have been hypothesised to rely mostly on nonlexical reading. Our experiments tested this hypothesis by assessing whether or not the deficit underlying dyslexia is specific to lexical reading. The effects of lexicality, word frequency and length were investigated in the same group of children in four separate experiments. Although dyslexics were slower and less accurate than skilled readers and had large length effects, they showed lexicality and word frequency effects in both reading aloud and lexical decision. In a cross‐experiment comparison, we show that a single global factor explains a large proportion of the difference in reading performance between dyslexic and skilled readers. This factor may indicate a deficit at a prelexical level of analysis. Lexical activation seemed spared in the dyslexic children based on the effects of lexicality and frequency. These findings contrast the hypothesis that Italian dyslexics primarily engage in nonlexical reading. 相似文献
5.
The development of spelling knowledge and its role in reading acquisition and reading disability 总被引：7，自引：0，他引：7
L C Ehri 《Journal of learning disabilities》1989,22(6):356-365
In contrast to the hypothesis that dyslexics possess phonological deficits that are neurological in origin, I suggest that the source of the deficit is primarily experiential--that dyslexics exhibit phonological deficits because they have not learned to read and spell in a way that develops their spelling knowledge so that it penetrates and comes to symbolize their phonological knowledge. Evidence from normal reading and spelling development as well as from comparisons of dyslexic and nondyslexic readers is offered to support this thesis. 相似文献
6.
Franklin R. Manis Patricia A. Szeszulski Liana K. Holt Kathryn Graves 《Annals of dyslexia》1988,38(1):139-153
In this paper we apply a developmental model of reading to the question of dyslexic subtypes. Groups of normal readers (n=40)
and dyslexic children (n=50), matched on reading level and IQ, were given a comprehensive test battery measuring level of
development of visual, phonological, and orthographic skills. As a group, dyslexics deviated from normal readers of equivalent
reading achievement primarily in phonological skills (spelling-to-sound translation and phonemic analysis), although limited
differences in knowledge of word-specific spellings were also observed. Dyslexics were superior to the younger normal readers
in visual processing of print. Analysis of individual data by reference to the reading level control group revealed three
major subgroups: a group with a specific deficit in phonological processing of print (52 percent), a group with deficits in
processing both the phonological and orthographic features of printed words (24 percent), and a group with phonological deficits
in language (8 percent). The remainder of the sample (16 percent) had specific deficits in visual or orthographic processing
of print, in spelling, or did not differ from the control group. The data support the view that most developmental dyslexics
have a specific language disorder involving some aspect of phonological processing. However, small subgroups with very different
configurations of reading and nonreading difficulties may exist as well.
This research was supported by an NICHD grant to the first author (USPHS grant 1 R23 HD20231). 相似文献
7.
ABSTRACTThis study presents a meta-analytic review of serial rapid automatized naming (RAN) deficits in individuals with dyslexia relative to typical readers (based on 216 effect sizes comprising 8335 dyslexic readers, 14,083 age-matched controls, and 921 reading-matched controls). A random-effects model analysis indicated a large impairment in speeded RAN in individuals with dyslexia compared with age-matched controls (d = 1.19) but a similar performance when compared with reading-matched controls (d = 0.13). In addition, dyslexic readers presented a deficit in discrete-naming formats (d = 0.74), although the deficit in serial RAN was notably larger; hence, adding seriality is particularly detrimental for these readers. The deficit appears to span all stimulus types (alphanumeric and nonalphanumeric), indicating that processes beyond letter processing are responsible for the delays and are independent of set size. Poor RAN is a long-term and universal symptom of dyslexia, and the transparency of the writing system does not influence its severity. 相似文献
8.
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
9.
Lisa M. Henderson Natassa Tsogka Margaret J. Snowling 《Journal of Research in Special Educational Needs》2013,13(1):57-65
Visual stress (the experience of visual distortions and discomfort during prolonged reading) is frequently identified and alleviated with coloured overlays or lenses. Previous studies have associated visual stress with dyslexia and as a consequence, coloured overlays are widely distributed to children and adults with reading difficulty. However, this practice remains controversial. We investigated whether overlays have advantageous and reliable benefits for reading in undergraduate students with and without dyslexia. Both groups read jumbled text faster with a coloured overlay than without. The dyslexic group did not show greater gains than controls, despite reporting significantly more symptoms of visual stress. However, coloured overlays did not improve reading rate or comprehension of connected text. The improvement in reading speed with an overlay was not reliable and was significantly reduced at retesting for dyslexic students. These results question the value of coloured overlays as a tool for identifying visual stress and as a form of remediation for the reading difficulties associated with dyslexia. 相似文献
10.
Repetition priming was used to examine whether children with dyslexia bias a lexical–semantic pathway when reading words aloud. For the dyslexic group (n = 18, age 9.4–11.8 years), but not for age‐matched controls (n = 18, age 9.2–12.4 years), reaction times when naming pictures were faster after naming the corresponding word. A reading age‐matched control group (n = 24, age 6.8–8.9 years) showed similar priming effects to the children with dyslexia. The magnitude of repetition priming was greater for children with dyslexia with poor nonword reading and slower picture naming. Assuming repetition priming of picture naming is contingent on accessing lexical phonology via semantics, the results suggest less‐skilled normal and disordered readers show a stronger bias towards a lexical– semantic pathway during word reading than skilled readers, and the severity of the phonological representations deficit modulates the strength of that bias in children with dyslexia. 相似文献
11.
In 1993, the Tennessee General Assembly voted funds to establish a model unit of integrated services and research to address
the full scope of issues associated with dyslexia. Dyslexia is characterized as significant difficulty in reading and spelling
individual words. In the Tennessee Center for the Study and Treatment of Dyslexia, these problems are presumed to be the consequence
of a phonological core deficit. When compared to typical readers, matched for age or reading level, dyslexic readers evidence
average listening comprehension, a relative strength in reading comprehension, deficits in word recognition and spelling,
and severe deficits in word analysis as well as in awareness and manipulation of phonemes. Integration of this information
yields a diagnostic profile that may be applied in the differential diagnosis of dyslexia both in clinical and school settings.
This paper presents an overview of the Tennessee Center for Dyslexia and the services it provides as well as its guidelines
for interpreting the results of norm-referenced tests and criterion-referenced measures to diagnose dyslexia and plan appropriate
intervention. Frith’s (1985, 1986) developmental framework for reading acquisition is integrated with the assessment data
to outline an instructional plan that addresses mastery of skills within and across the hierarchical phases—logographic, alphabetic,
and orthographic—of reading development. 相似文献
12.
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
13.
14.
Dyslexia is a specific learning disability characterized by difficulties with accurate and/or fluent word recognition and
by poor spelling abilities. The absence of other high level cognitive deficits in the dyslexic population has led some authors
to propose that non-strategical processes like implicit learning could be impaired in this population. Most studies have addressed
this issue by using sequence learning tasks, but so far the results have not been conclusive. We test this hypothesis by comparing
the performance of dyslexic children and good readers in both implicit and explicit versions of the sequence learning task,
as well as in another implicit learning task not involving sequential information. The results showed that dyslexic children
failed to learn the sequence when they were not informed about its presence (implicit condition). In contrast, they learned
without significant differences in relation to the good readers group when they were encouraged to discover the sequence and
to use it in order to improve their performance (explicit condition). Moreover, we observed that this implicit learning deficit
was not extended to other forms of non-sequential, implicit learning such as contextual cueing. In this case, both groups
showed similar implicit learning about the information provided by the visual context. These results help to clarify previous
contradictory data, and they are discussed in relation to how the implicit sequence learning deficit could contribute to the
understanding of dyslexia. 相似文献
15.
Kevin K. H. Chung Jason C. M. Lo Connie S.-H. Ho Xiaoyun Xiao David W. Chan 《Annals of dyslexia》2014,64(3):222-247
This study aims to investigate the relation of syntactic and discourse skills to morphological skills, rapid naming, and working memory in Chinese adolescent readers with dyslexia and to examine their cognitive–linguistic profiles. Fifty-two dyslexic readers (mean age, 13;42) from grade 7 to 9 in Hong Kong high schools were compared with 52 typically developing readers of the same chronological age (mean age, 13;30) in the measures of word reading, 1-min word reading, reading comprehension, morpheme discrimination, morpheme production, morphosyntactic knowledge, sentence order knowledge, digit rapid naming, letter rapid naming, backward digit span, and non-word repetition. Results showed that dyslexic readers performed significantly worse than their peers on all the cognitive-linguistic tasks. Analyses of individual performance also revealed that over half of the dyslexic readers exhibited deficits in syntactic and discourse skills. Moreover, syntactic skills, morphological skills, and rapid naming best distinguished dyslexic from non-dyslexic readers. Findings underscore the significance of syntactic and discourse skills for understanding reading impairment in Chinese adolescent readers. 相似文献
16.
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
17.
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
18.
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
19.
Leinonen Seija Müller Kurt Leppänen Paavo H.T. Aro Mikko Ahonen Timo Lyytinen Heikki 《Reading and writing》2001,14(3-4):265-296
Subgroups of Finnish dyslexic adults (N = 84)displaying, relative to each other, a distinctivecombination of accuracy and speed of oral text readingwere compared in phonological and orthographicprocessing, verbal short-term memory and readinghabits. Inaccurate phonological decoding appeared todetermine the number of errors made in text reading,while inability to utilize effectively rapid lexicalaccess of words manifested as slow text reading speed.Phonological and orthographic word recognitionprocesses were less tightly integrated among dyslexicthan normal readers. Our results indicate thatadvanced orthographic processing skills might help anumber of the dyslexic readers to compensate for theirserious phonological deficits. The subgroups alsodiffered from each other in reading habits. Arelatively fast reading speed, even with numerouserrors, appears to be more rewarding in everydayreading than a slower but more accurate readingstyle. 相似文献
20.
The current study examined the use of sublexical clusters in normal and dyslexic readers. We focused primarily on onset consonantal clusters, but the use of rimes and digraphs was also considered. A segmentation paradigm, the separation of two adjacent letters in a word by a nonletter symbol, was used. We hypothesized that the effect of this distortion on reading would be larger if two adjacent letters functioned as a cluster. In the first study, naming and lexical decision tasks were administered to 24 normal reading and 24 dyslexic fourth-grade children. In a second study, the same tasks were administered to 24 skilled adult readers. The results did not support the use of consonantal onsets and rimes during reading. However, we did find that digraphs were used, because their distortion had a relatively large effect on reading speed. This effect was similar in normal and dyslexic readers. 相似文献