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1.
Richard K. Olson 《Reading and writing》2007,20(1-2):1-11
This introduction to the special issue on Genes, Environment, and Reading presents an overview of the background for behavior-
and molecular-genetic research on dyslexia and individual differences across the normal range. The general methods, questions
addressed, and selected results are summarized for each of the papers in the order of their presentation in the special issue.
Concluding comments reflect on the influence of environmental range on estimates of genetic and environmental influences,
and the future of behavior- and molecular-genetic research on reading. 相似文献
2.
Stefan Samuelsson Richard Olson Sally Wadsworth Robin Corley John C. DeFries Erik Willcutt Jacqueline Hulslander Brian Byrne 《Reading and writing》2007,20(1-2):51-75
Genetic and environmental influences on prereading skills in preschool and on early reading and spelling development at the
end of kindergarten were compared among samples of identical and fraternal twins from the U.S. (Colorado), Australia, and
Scandinavia. Mean comparisons revealed significantly lower preschool print knowledge in Scandinavia, consistent with the relatively
lower amount of shared book reading and letter-based activities with parents, and lack of emphasis on print knowledge in Scandinavian
preschools. The patterns of correlations between all preschool environment measures and prereading skills within the samples
were remarkably similar, as were the patterns of genetic, shared environment, and non-shared environment estimates: in all
samples, genetic influence was substantial and shared environment influence was relatively weak for phonological awareness,
rapid naming, and verbal memory; genetic influence was weak, and shared environment influence was relatively strong for vocabulary
and print knowledge. In contrast, for reading and spelling assessed at the end of kindergarten in the Australian and U.S.
samples, there was some preliminary evidence for country differences in the magnitude of genetic and environmental influences.
We argue that the apparently higher genetic and lower shared environment influence in the Australian sample was related to
a greater emphasis on formal reading instruction, resulting in more advanced reading and spelling skills at the end of kindergarten,
and thus there was greater opportunity to observe genetic influences on response to systematic reading instruction among the
Australian twins. 相似文献
3.
Micaela E. Christopher Jacqueline Hulslander Brian Byrne Stefan Samuelsson Janice M. Keenan Bruce Pennington 《Scientific Studies of Reading》2013,17(5):350-368
We explored the etiology of individual differences in reading development from post-kindergarten to post–4th grade by analyzing data from 487 twin pairs tested in Colorado. Data from three reading measures and one spelling measure were fit to biometric latent growth curve models, allowing us to extend previous behavioral genetic studies of the etiology of early reading development at specific time points. We found primarily genetic influences on individual differences at post–1st grade for all measures. Genetic influences on variance in growth rates were also found, with evidence of small, nonsignificant, shared environmental influences for two measures. We discuss our results, including their implications for educational policy. 相似文献
4.
The primary objectives of the present study are to introduce the Colorado Longitudinal Twin Study of Reading Disability, the
first longitudinal twin study in which subjects have been specifically selected for having a history of reading difficulties,
and to present some initial assessments of the stability of reading performance and cognitive abilities in this sample. Preliminary
examination of the test scores of 124 twins with a history of reading difficulties and 154 twins with no history of reading
difficulties indicates that over the 5- to 6-year interval between assessments, cognitive and reading performance are highly
stable. As a group, those subjects with a history of reading difficulties had substantial deficits relative to control subjects
on all measures at initial assessment, and significant deficits remained at follow-up. The stability noted for all cognitive
and achievement measures was highest for a composite measure of reading, whose average stability correlation across groups
was 0.80. Results of preliminary behavior genetic analyses for this measure indicated that shared genetic influences accounted
for 86% and 49% of the phenotypic correlations between the two assessments for twin pairs with and without reading difficulties,
respectively. In addition, genetic correlations reached unity for both groups, suggesting that the same genetic influences
are manifested at both time points. 相似文献
5.
There is a growing body of evidence that children with dyslexia have problems not just in reading but in a range of skills
including several unrelated to reading. In an attempt to compare the severity and incidence of deficits across these varied
domains, children with dyslexia (mean ages 8, 12, and 16 years), and control groups of normally achieving children matched
for IQ and for age or reading age, were tested on a range of primitive (basic) skills. The children with dyslexia performed
significantly worse than the same-age controls on most tasks, and significantly worse even than the reading-age controls on
phoneme segmentation, picture naming speed, word tachistoscopic word recognition, speeded bead threading and some balance
tasks. The overall performance of the children with dyslexia is interpreted as showing less complete automatization than normal. 相似文献
6.
Janice M. Keenan Rebecca S. Betjemann Sally J. Wadsworth John C. DeFries Richard K. Olson 《Journal of Research in Reading》2006,29(1):75-91
We report preliminary behaviour genetic analyses of reading and listening comprehension from The Colorado Learning Disabilities Research Center. Although the twin sample with these new measures is still of limited size, we find substantial, and significant, genetic influences on individual differences in both reading and listening comprehension. In addition, word recognition and listening comprehension each accounted for significant independent genetic influences on reading comprehension. Together, they accounted for all the genetic influence on reading comprehension, indicating a largely genetic basis for the ‘simple model’ of individual differences in reading comprehension proposed by Hoover and Gough (1990) . 相似文献
7.
Brian Byrne Cara Delaland Ruth Fielding-Barnsley Peter Quain Stefan Samuelsson Torleiv Høien Robin Corley John C. DeFries Sally Wadsworth Erik Willcutt Richard K. Olson 《Annals of dyslexia》2002,52(1):47-73
We have initiated parallel longitudinal studies in Australia (Byrne, PI), the United States (Olson, PI), and Norway (Samuelsson,
PI) of identical and fraternal twins who are being tested in preschool for prereading skills, and in kindergarten, first grade,
and second grade for the development of early reading, spelling, and related cognitive skills. Comparisons of the similarities
of identical and fraternal twins will reveal the relative influence of genetic, shared family environment, and nonshared environment
on individual differences at and across different stages of development. Family and twin-specific environmental information
is also being directly assessed through parent questionnaires and observations by testers. Most of the data collected so far
have been from preschool twins (146 in Australia, 284 in the United States, and 70 in Norway). Preliminary analyses for the
preschool cognitive measures showed reliable genetic influences on phonological awareness and several measures of memory and
learning. In contrast, vocabulary, grammar, and morphology showed significant shared environment and negligible genetic effects.
A print knowledge composite showed both genetic and shared environment influence. 相似文献
8.
Brian Byrne Stefan Samuelsson Sally Wadsworth Jacqueline Hulslander Robin Corley John C. DeFries Peter Quain Erik G. Willcutt Richard K. Olson 《Reading and writing》2007,20(1-2):77-102
Grade 1 literacy skills of twin children in Australia (New South Wales) and the United States (Colorado) were explored in
a genetically sensitive design (N = 319 pairs). Analyses indicated strong genetic influence on word and nonword identification, reading comprehension, and
spelling. Rapid naming showed more modest, though reliable, genetic influence. Phonological awareness was subject to high
nonshared environment and no reliable genetic effects, and individual measures of memory and learning were also less affected
by genes than nonshared environment. Multivariate analyses showed that the same genes affected word identification, reading
comprehension, and spelling. Country comparisons indicated that the patterns of genetic influence on reading and spelling
in Grade 1 were similar, though for the U.S. but not the Australian children new genes came on stream in the move from kindergarten
to Grade 1. We suggest that this is because the more intensive kindergarten literacy curriculum in New South Wales compared
with Colorado, consistent with the mean differences between the two countries, means that more of the genes are “online” sooner
in Australia because of accelerated overall reading development. 相似文献
9.
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
10.
The genetic and environmental origins of learning abilities and disabilities in the early school years 总被引：3，自引：0，他引：3
Kovas Y Haworth CM Dale PS Plomin R 《Monographs of the Society for Research in Child Development》2007,72(3):vii, 1-vii144
Despite the importance of learning abilities and disabilities in education and child development, little is known about their genetic and environmental origins in the early school years. We report results for English (which includes reading, writing, and speaking), mathematics, and science as well as general cognitive ability in a large and representative sample of U.K. twins studied at 7, 9, and 10 years of age. Although preliminary reports of some of these data have been published, the purpose of this monograph is to present new univariate, multivariate, and longitudinal analyses that systematically examine genetic and environmental influences for the entire sample at all ages for all measures for both the low extremes (disabilities) and the entire sample (abilities). English, mathematics, and science yielded similarly high heritabilities and modest shared environmental influences at 7, 9, and 10 years despite major changes in content across these years. We draw three conclusions that go beyond estimating heritability. First, the abnormal is normal: Low performance is the quantitative extreme of the same genetic and environmental influences that operate throughout the normal distribution. Second, continuity is genetic and change is environmental: Longitudinal analyses suggest that age-to-age stability is primarily mediated genetically, whereas the environment contributes to change from age to age. Third, genes are generalists and environments are specialists: Multivariate analyses indicate that genes largely contribute to similarity in performance within and between the three domains--and with general cognitive ability--whereas the environment contributes to differences in performance. These conclusions have far-reaching implications for education and child development as well as for molecular genetics and neuroscience. 相似文献
11.
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
12.
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
13.
Cross-linguistic studies provide a unique tool for the identification of universal processes in oral and written language, both in development and in breakdown (Annual Review of psychology, 52, 369–396). Examining the differential strengths and weaknesses of children with dyslexia in contrasting orthographies can help illumine both the more universal aspects of reading disabilities, as well as their individual language-specific attributes. The aim of this study, was to investigate the shared and distinctive characteristics of readers with dyslexia on reading and reading fluency across Hebrew and English orthographies. Differences between 60 Hebrew and English-speaking children with dyslexia on a battery of cognitive, linguistic, and reading measures will be discussed along with theoretical implications. 相似文献
14.
The reading levels and reading strategies of 43 children with genetic dyslexia, right-hemisphere lesions/dysfunction, and
left-hemisphere lesions/dysfunction were retrospectively compared. Age and IQ were comparable. Only children who had a verbal
or performance IQ over 90 were included in the study. Although the genetic dyslexics had a significantly higher Full Scale
IQ than the other two groups, their reading level was significantly lower. This suggests that a disturbance of the normal
processes of neuronal migration during fetal development may have profound effects on specific cognitive processes, without
affecting others. In contrast, 50 percent of the boys with left-hemisphere deficits were disabled readers. One-third of the
boys with right-hemisphere deficits were also poor readers. With one exception, the girls, who had comparable deficits, were
good readers. A comparison was made between the groups in terms of reading strategies and patterns of errors. 相似文献
15.
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
16.
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
17.
Although genetic influences on individual differences in activity level (AL) are well documented, few studies have considered the etiology of AL from a contextual perspective. In the present study, cross-situational and context-specific genetic effects on individual differences in AL at age 2 were examined. The AL of 312 twin pairs (144 monozygotic and 168 dzygotic) was mechanically assessed with actigraphs in the home and in laboratory test and play situations. AL displayed significant genetic variance in all 3 situations. Moreover, actigraph scores significantly correlated across situations. Multivariate genetic model-fitting analyses found that the observed cross-situational continuity in AL was due entirely to genetic factors. Situational differences in AL arise from genetic, shared environmental, and nonshared environmental influences. 相似文献
18.
Previous twin studies of reading disability employed a comparison of concordance rates in identical and fraternal twin pairs
as a test for genetic etiology. Recently, a statistically more powerful multiple regression analysis of twin data has been
formulated to assess the importance of genetic factors in the development of reading difficulties. Application of this analysis
to twin data from the Colorado Reading Project yields definitive evidence for a genetic etiology. Results from this study
suggest that approximately 40 percent of the deficit observed in the disabled readers is due to genetic factors, 35 percent
is due to environmental influences shared by members of twin pairs, and about 25 percent is the result of environmental factors
unique to the individual and/or error variance.
This work was supported in part by a program project grant from the NICHD (HD-11681). 相似文献
19.
Brian Byrne Richard K. Olson Stefan Samuelsson Sally Wadsworth Robin Corley John C. DeFries Erik Willcutt 《Journal of Research in Reading》2006,29(1):33-49
Prereading and early reading skills of preschool twin children in Australia, Scandinavia and the United States were explored in a genetically sensitive design (max. N=627 preschool pairs and 422 kindergarten pairs). Analyses indicated a strong genetic influence on preschool phonological awareness, rapid naming and verbal memory. Print awareness, vocabulary and grammar/morphology were subject primarily to shared environment effects. There were significant genetic and shared environment correlations among the preschool traits. Kindergarten reading, phonological awareness and rapid naming were primarily affected by genes, and spelling was equally affected by genes and shared environment. Multivariate analyses revealed genetic and environmental overlap and independence among kindergarten variables. Longitudinal analyses showed genetic continuity as well as change in phonological awareness and rapid naming across the 2 years. Relations among the preschool variables of print awareness, phonological awareness and rapid naming and kindergarten reading were also explored in longitudinal analyses. Educational implications are discussed. 相似文献
20.
Coventry WL Byrne B Olson RK Corley R Samuelsson S 《Journal of learning disabilities》2011,44(4):322-329
The genetic and environmental overlap between static and dynamic measures of preschool phonological awareness (PA) and their relation to preschool letter knowledge (LK) and kindergarten reading were examined using monozygotic and dizygotic twin children (maximum N = 1,988). The static tests were those typically used to assess a child's current level of PA such as blending and elision, and the dynamic test included instruction in phoneme identity to assess the child's ability to respond to this instruction. Both forms were influenced by genes and by shared and nonshared environment. The static and dynamic versions were influenced by the same genes, and part of the total genetic influence was shared with LK. They were subject to both overlapping and independent shared environment influences, with the component in common also affecting LK. Nonshared environment influences were mostly independent. Scores from dynamic assessment added only minimally to variance explained in kindergarten reading after LK and static assessment had been factored in. Although one of the genetic factors that influenced both forms of PA also affected kindergarten reading, it was only the one shared with LK. The authors conclude that dynamic assessment of PA in preschool offers little advantage over the more commonly used static forms, especially if LK scores are available, although they acknowledge its potential in cases of preschool educational disadvantage. 相似文献