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1.

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.

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2.
Limited research has examined the skills of children with a reading disability (RD) and children with RD and a mathematics disability (MD). Even less research has examined the phonological awareness (PA) and rapid automatized naming (RAN) skills in these two groups of children and how these skills relate to reading and math achievement. Additionally, various classification criteria are frequently implemented to classify children with MD. The purpose of this study, therefore, was to examine the PA and RAN skills in children who met different criteria for RD only and children with RD who are at risk for mathematics difficulties (MDR). Participants were 114 second‐ or third‐grade students with RD from public elementary schools in three large metropolitan areas. Students were classified as at risk for mathematics difficulties utilizing a 25th‐percentile cutoff and a 15th‐percentile cutoff as assessed by the KeyMath‐Revised Test ( Connolly, 1988 ). A series of PA and RAN measures were administered along with a range of reading and mathematics measures. Hierarchical regression analyses indicated that children with RD only evidenced a different pattern of results compared to children with RD + MDR. Additionally, using a more stringent criterion to classify children at risk for mathematics difficulties resulted in a differential pattern of results when compared to a less stringent classification criterion.  相似文献   

3.
The purpose of this study was to describe the mathematical problem-solving profiles of students with mathematics disabilities (MD) with and without comorbid reading disabilities (RD). The disability status of fourth-grade students was verified through testing (n = 18 MD; n = 22 MD + RD). Then a hierarchy of mathematics problem-solving tasks was administered. The results demonstrated large deficits for both groups; however, the differences between students with MD and those with MD + RD were mediated by the level of problem solving (arithmetic story problems vs. complex story problems vs. real-world problem solving) and by performance dimension (operations vs. problem solving). On arithmetic story problems, the differences between the disability subtypes were similar for operations and problem solving. By contrast, on complex story problems and real-world problem solving, the differences between the subtypes were larger for problem solving than for operations.  相似文献   

4.
The double-deficit hypothesis (Wolf, 1997; Wolf & Bowers, 1999, this issue) contends that deficits in phonological awareness and deficits in visual naming speed represent two independent causal impediments to reading acquisition for children with developmental reading disabilities (RD). One hundred and sixty-six children with severe RD from 7 to 13 years of age were classified into three deficit subgroups according to a double-deficit framework. A total of 140 children with RD, 84% of the sample, were classified; 54% demonstrated a double deficit (DD), 22% a phonological deficit only (PHON), and 24% a visual-naming speed deficit only (VNS). Diagnostic test profiles highlighted the joint contributions of the two core deficits in depressing written language acquisition. The children in the DD group were more globally impaired than those in the other subgroups, and the VNS group children were the highest achieving and most selectively impaired readers. Following 35 hours of word identification training, sizable gains and significant generalization of training effects were achieved by all subgroups. A metacognitive phonics program resulted in greater generalized effects across the domain of real English words, and a phonological training program produced superior outcomes within the phonological processing domain. The greatest non-word reading gains were achieved by children with only phonological deficits.  相似文献   

5.
Using functional magnetic resonance imaging, we investigated multimodal (visual and auditory) semantic and unimodal (visual only) phonological processing in reading disabled (RD) adolescents and non-impaired (NI) control participants. We found reduced activation for RD relative to NI in a number of left-hemisphere reading-related areas across all processing tasks regardless of task type (semantic vs. phonological) or modality (auditory vs. visual modality). Moreover, activation differences in these regions, which included the inferior frontal gyrus, the superior temporal gyrus, and the occipitotemporal region, were largely independent of in-scanner performance in our auditory semantic task. That is, although RD participants and NI participants differed in performance in visually presented conditions, they did not differ significantly in the auditory condition, yet similar patterns of reduced activation were observed in these regions across conditions. These findings indicate a neurobiological marker in RD that is independent of task, modality, or performance. These findings are discussed in the context of current neurobiological models of RD.  相似文献   

6.
ABSTRACT— The majority of children who receive special education services meet criteria for reading disability (RD) or attention-deficit/hyperactivity disorder (ADHD), but additional research is needed to understand the long-term academic outcome of children in these groups. Individuals with RD only ( N = 71), ADHD only ( N = 66), both RD and ADHD ( N = 51), or neither disorder ( N = 118) were identified through the ongoing Colorado Learning Disabilities Research Center twin study and retested 5 years later. Results of the follow-up testing indicated that, in addition to ongoing reading difficulties, individuals with RD exhibited higher rates of academic difficulties, depression, and adolescent-onset conduct disorder. Initial ADHD status was associated with academic and social difficulties and elevated rates of nearly all comorbid disorders 5 years later. The group with comorbid RD and ADHD had more stable reading deficits than the group with RD without ADHD and exhibited greater impairment than groups with either disorder alone on outcome measures of academic functioning and social difficulties. These results suggest that individuals with both RD and ADHD are at increased risk for negative outcomes as adolescents and young adults and that when RD and ADHD co-occur, interventions should be provided for both disorders.  相似文献   

7.
ABSTRACT

We investigated the double-deficit hypothesis (DDH) in samples of U.S. (N = 489), Australian (N = 264), and Scandinavian (N = 293) children followed from preschool to grade 2. Children were assigned to double deficit, single deficit and no deficit subtypes in preschool, kindergarten, and grade 1 and compared on reading and spelling in grades 1 and 2. In most analyses, the double deficit subtype scored significantly lower in reading and spelling than the single deficits, a pattern of findings that was identical across samples. Moreover, across countries, RAN deficits showed a stronger effect on reading whereas PA deficits showed stronger effects on spelling. Overall, the results supported the basic premises of the DDH suggesting that the double deficit subtype represents the most impaired readers, and that RAN and PA are separable deficits with different effects on reading and spelling. The results also supported a universal view of literacy development, with similar predictive patterns of DDH subtypes across orthographies.  相似文献   

8.
Reading-related skills were tested in adults with and without reading disabilities (RD) and adults with profound hearing impairment (PHI) who did not differ on average Performance IQ. The RD group and the PHI group both demonstrated levels of phonological awareness lower than the control group's, but only the RD group also exhibited deficits in other skills, including verbal short-term memory, morphological awareness, speeded written naming, and reading comprehension. The average reading level of the PHI group was significantly higher than that of the RD group. Three control group members also demonstrated limited phonological awareness without other deficits in a pilot study, performing similarly to the PHI group. The results support other studies suggesting that processes dependent on memory, not solely phonological awareness, may contribute to determining reading achievement.  相似文献   

9.
The purpose of this study was to investigate whether changes in working memory (WM) of children with reading disabilities (RD) were related to a domain-specific or a domain-general system. Based on Daneman and Carpenter's (1980) Sentence Listening Span task, children were subgrouped into a group of high executive processing (high listening span) children without RD, a group of low executive processing (low listening span) children with RD, and a group of children with and without RD matched on executive processing (moderate listening span). Subgroups were compared on phonological, visual-spatial, and semantic WM tasks across initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The results showed that (a) children without RD high in executive processing ability outperformed all other subgroups, (b) the RD subgroup low in executive processing performed poorly relative to all other subgroups across task and memory conditions, (c) children with and without RD matched on executive processing were comparable in WM span and changes in WM for all tasks, and (d) WM performance of children with RD was a strong linear function of the high executive processing group, suggesting that the nature or the specific componential makeup of the tasks are not the main contributors to WM performance. Taken together, the results suggest that a domain-general system may partially contribute to poor WM in children with RD, and that this system may operate independently of their reading deficits.  相似文献   

10.
The present study investigated the persistent nature of naming speed deficits within the context of the double-deficit hypothesis in a university sample of adults with reading disabilities (RD). Twenty-five university students with RD were compared to 28 typically achieving readers on measures of reading skill, phonological processing, and naming speed. The results indicated that both naming speed and phonological processing deficits characterized the RD group. In a regression analysis, neither naming speed nor phonological processing were important variables in explaining comprehension when reading rate was in the model. The results of the present study are mixed at best and are consistent with earlier conclusions that support for the double-deficit hypothesis of dyslexia remains limited.  相似文献   

11.
The present study examined the comorbidity between attention-deficit/hyperactivity disorder (ADHD) and reading disability (RD) in male adults. Participants were 120 men, of whom 24 were classified as having ADHD. The basis for the diagnosis was two self-report scales validated by interviews and background data. An extensive battery was used to assess phonological abilities and various aspects of reading skills. No differences were obtained between adults with and without ADHD on measures of either phonological processing skills or word decoding, indicating a low comorbidity with RD. This finding was valid even when different criteria were used to diagnose RD. However, the two groups differed in reading comprehension, with individuals with ADHD performing poorly in tests of reading comprehension. These results are compatible with the view that reading comprehension involves many of the higher cognitive control functions assumed to be impaired in ADHD. However, these attentional control functions are not critical to word recognition, which is determined by a more encapsulated phonological processing module. The pattern of associations between ADHD and RD observed in the present study is explained with reference to the differential attentional demands of the two aspects of reading.  相似文献   

12.
It has been proposed that the phonological coredeficit that is linked to reading failure hasas its underlying cause a deficit in temporalprocessing. In a multivariate investigationdesigned to examine the temporal processingdeficit hypothesis, thirty reading-disabled(RD) adults, thirty-two normally achievingadults and thirty-one normally achievingchildren (reading-level controls) wereadministered a comprehensive battery thatincluded a wide range of timing tasks, inaddition to reading and phonological measures. Although adults with RD displayed overallperformance that was below that of normallyachieving adults on most of the timing tasks,their performance was not differentiallyinfluenced by rate of stimulus presentation. Although the RD adults displayed the typicalpattern of impaired phonological awareness andpseudoword reading relative to reading-levelmatched children, the reading-disabled adultsoutperformed the children on the timing tasks. Finally, with the exception of continuousnaming, the timing tasks shared little variancewith phonological sensitivity and contributedlittle unique variance to word reading. Although these findings undermine the timingdeficit hypothesis, they do provide evidencefor the involvement of naming deficits inreading disability.  相似文献   

13.
This article reviews the results of a meta-analysis of the experimental published literature that compares the academic, cognitive, and behavioral performance of adults with reading disabilities (RD) with average achieving adult readers. The meta-analysis shows that deficits independent of the classification measures emerged for adults with RD on measures of vocabulary, math, spelling, and specific cognitive process related to naming speed, phonological processing, and verbal memory. The results also showed that adults with high verbal IQs (scores > 100) but low word recognition standard scores (< 90) yielded greater deficits related to their average reading counterparts when compared to studies that included adults with RD with verbal IQ and reading scores in the same low range. Implications of the findings related to assessment and intervention are discussed.  相似文献   

14.
It is not clear from research whether, or to what extent, reading comprehension is impaired in adults who have learning disabilities (LD). The influence of perceptual organization (PO) and phonological awareness (PA) on reading comprehension was investigated. PO and PA are cognitive functions that have been examined in previous research for their roles in nonverbal LD and phonological dyslexia, respectively. Nonverbal tests of PO and non-reading tests of PA were administered to a sample of adults with postsecondary education. Approximately two thirds of the sample had previously been diagnosed as having LD. In a multiple regression analysis, tests of PO and PA were used to predict scores for tests of reading comprehension and mechanics. Despite the nonverbal nature of the perceptual organizational test stimuli, PO strongly predicted reading comprehension. Tests of PA predicted decoding and reading speed. Results were interpreted as supporting the hypothesis that integrative processes usually characterized as nonverbal were nonetheless used by readers with and without disabilities to understand text. The study’s findings have implications for understanding the reading of adults with learning disabilities, and the nature of reading comprehension in general.  相似文献   

15.
When one or both parents have a history of developmental reading disorder (RD) in childhood, the risk to their offspring for developing reading problems is substantially increased. However, risk research has usually assumed a stability of reading problems across the lifespan (i.e., if a parent was affected in childhood, he or she remains affected in adulthood). Yet, some individuals with RD in childhood compensate for the disorder as they grow older. Both an environmental and genetic hypothesis would predict that the risk for RD in offspring will vary as a function of parental compensation. This study examined whether risk to offspring was dependent on the parents' successful or unsuccessful compensation for their childhood reading problems. Two large family data sets were analyzed (N=907). Diagnoses with either an age discrepant or IQ discrepant criteria essentially showed that having at least one still affected parent (i.e., RD both as a child and as an adult) put the offspring at a higher risk for RD than having at least one compensated parent (i.e., RD as a child but not as an adult). The lowest risk to an offspring occurred when both parents were never affected (i.e., not RD as a child or as an adult). The implications of these findings are discussed with regard to counseling and early diagnosis of reading problems.  相似文献   

16.
17.
The current meta-analysis synthesized findings from profiling research on Chinese children with reading difficulties (RD). We reviewed a total of 81 studies published between 1964 and May 2015, representing a total of 9735 Chinese children. There are 982 effect sizes for the comparison between children with RD and age-matched typically developing (A-TD) children and 152 effect sizes for the comparison between children with RD and reading-level-matched typically developing (R-TD) children on multiple linguistic and cognitive skills. Results showed that compared to A-TD children, children with RD have severe deficits in morphological awareness, orthographic knowledge, phonological awareness, rapid naming, working memory, and visual skills and moderate deficits in short-term memory and motor skills. Compared to R-TD children, children with RD only have moderate deficits in rapid naming and mild deficits in orthographic knowledge. Moderation analyses for the comparison between RD and A-TD children revealed that children with more severe RD show more severe deficits in morphological awareness, phonological awareness, rapid naming, and visual skills. However, neither location (Mainland vs. Hong Kong) nor type of reading screening (character recognition vs. character recognition combined with reading comprehension) emerged as a moderator of the deficit profiles. These findings indicate that Chinese children with RD have deficits on a wide range of cognitive and linguistic skills. Deficits in rapid naming and orthographic knowledge may be potential causal factors for RD in Chinese based on existing evidence. Implications for the diagnosis and instructions of Chinese children with RD were discussed.  相似文献   

18.
The aims of this study were (a) to determine whether Spanish children with reading disabilities (RD) show a speech perception deficit and (b) to explore the locus and nature of this perceptive deficit. A group of 29 children with RD, 41 chronological age-matched controls, and 27 reading ability-matched younger controls were tested on tasks of speech perception. The effect of linguistic unit (word vs. syllable) and type of phonetic contrast (voicing, place and manner of articulation) were analyzed in terms of the number of errors and the response time. The results revealed a speech perception deficit in Spanish children with RD that was independent of the type of phonetic contrast and of linguistic unit.  相似文献   

19.
Reading difficulty (RD; or dyslexia) is a heritable condition characterized by slow, inaccurate reading accompanied by executive dysfunction, specifically with respect to visual attention. The current study was designed to examine the effect of familial history of RD on the relationship between reading and visual attention abilities in children with RD using a functional MRI reading task. Seventy-one children with RD participated in the study. Based on parental reports of the existence of RD in one or both of each child’s parents, children with RD were divided into two groups: (1) those with a familial history of RD and (2) those without a familial history of RD. Reading and visual attention measures were collected from all participants. Functional MRI data during word reading was acquired in 30 participants of the entire cohort. Children with or without a familial history of RD demonstrated below-average reading and visual attention scores, with greater interaction between these measures in the group with a familial history of RD. Greater bilateral and diffused activation during word reading also were found in this group. We suggest that a familial history of RD is related to greater association between lower reading abilities and visual attention abilities. Parental history of RD therefore may be an important preschool screener (before reading age) to prompt early intervention focused on executive functions and reading-related skills.  相似文献   

20.
The majority of work on the double-deficit hypothesis (DDH) of dyslexia has been done at the letter and word levels of reading. Key research questions addressed in this study are (a) do readers with different subtypes of dyslexia display differences in fluency at particular reading levels (e.g., letter, word, and connected text)? and (b) do children with dyslexia identified by either low-achievement or ability-achievement discrepancy criteria show similar differences when classified by the DDH? To address these questions, the authors assessed a sample of 158 children with severe reading impairments in second and third grades on an extensive battery and classified them into three reader subtypes using the DDH. The results demonstrated that the three DDH subtypes exhibited differences in fluency at different levels of reading (letter, word, and connected text), underscoring the separate reading profiles of these subtypes and the different possible routes to dysfluency in reading disabilities. Furthermore, the results suggest that the different patterns among DDH subtypes are primarily driven by the ability-achievement discrepancy group. The implications of these findings are discussed for intervention, reading theory, and a more refined understanding of heterogeneity.  相似文献   

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