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Wei W, Ma S, Fu B, Song R, Guo H. Human-specific insights into candidate genes and boosted discoveries of novel loci illuminate roles of neuroglia in reading disorders. GENES, BRAIN, AND BEHAVIOR 2024; 23:e12899. [PMID: 38752599 PMCID: PMC11097622 DOI: 10.1111/gbb.12899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/19/2024]
Abstract
Reading disorders (RD) are human-specific neuropsychological conditions associated with decoding printed words and/or reading comprehension. So far only a handful of candidate genes segregated in families and 42 loci from genome-wide association study (GWAS) have been identified that jointly provided little clues of pathophysiology. Leveraging human-specific genomic information, we critically assessed the RD candidates for the first time and found substantial human-specific features within. The GWAS candidates (i.e., population signals) were distinct from the familial counterparts and were more likely pleiotropic in neuropsychiatric traits and to harbor human-specific regulatory elements (HSREs). Candidate genes associated with human cortical morphology indeed showed human-specific expression in adult brain cortices, particularly in neuroglia likely regulated by HSREs. Expression levels of candidate genes across human brain developmental stages showed a clear pattern of uplifted expression in early brain development crucial to RD development. Following the new insights and loci pleiotropic in cognitive traits, we identified four novel genes from the GWAS sub-significant associations (i.e., FOXO3, MAPT, KMT2E and HTT) and the Semaphorin gene family with functional priors (i.e., SEMA3A, SEMA3E and SEMA5B). These novel genes were related to neuronal plasticity and disorders, mostly conserved the pattern of uplifted expression in early brain development and had evident expression in cortical neuroglial cells. Our findings jointly illuminated the association of RD with neuroglia regulation-an emerging hotspot in studying neurodevelopmental disorders, and highlighted the need of improving RD phenotyping to avoid jeopardizing future genetic studies of RD.
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Affiliation(s)
- Wen‐Hua Wei
- Centre for Biostatistics, Division of Population Health, Health Services Research and Primary CareThe University of ManchesterManchesterUK
| | - Shaowei Ma
- Hebei Key Laboratory of Children's Cognition and Digital Education and School of Foreign LanguagesLangfang Normal UniversityLangfangChina
| | - Bo Fu
- School of Data ScienceFudan UniversityShanghaiChina
| | - Ranran Song
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Laboratory of Environment and Health, School of Public Health, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Hui Guo
- Centre for Biostatistics, Division of Population Health, Health Services Research and Primary CareThe University of ManchesterManchesterUK
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2
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Blockmans L, Kievit R, Wouters J, Ghesquière P, Vandermosten M. Dynamics of cognitive predictors during reading acquisition in a sample of children overrepresented for dyslexia risk. Dev Sci 2024; 27:e13412. [PMID: 37219071 DOI: 10.1111/desc.13412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 04/07/2023] [Accepted: 05/09/2023] [Indexed: 05/24/2023]
Abstract
Literacy acquisition is a complex process with genetic and environmental factors influencing cognitive and neural processes associated with reading. Previous research identified factors that predict word reading fluency (WRF), including phonological awareness (PA), rapid automatized naming (RAN), and speech-in-noise perception (SPIN). Recent theoretical accounts suggest dynamic interactions between these factors and reading, but direct investigations of such dynamics are lacking. Here, we investigated the dynamic effect of phonological processing and speech perception on WRF. More specifically, we evaluated the dynamic influence of PA, RAN, and SPIN measured in kindergarten (the year prior to formal reading instruction), first grade (the first year of formal reading instruction) and second grade on WRF in second and third grade. We also assessed the effect of an indirect proxy of family risk for reading difficulties using a parental questionnaire (Adult Reading History Questionnaire, ARHQ). We applied path modeling in a longitudinal sample of 162 Dutch-speaking children of whom the majority was selected to have an increased family and/or cognitive risk for dyslexia. We showed that parental ARHQ had a significant effect on WRF, RAN and SPIN, but unexpectedly not on PA. We also found effects of RAN and PA directly on WRF that were limited to first and second grade respectively, in contrast to previous research reporting pre-reading PA effects and prolonged RAN effects throughout reading acquisition. Our study provides important new insights into early prediction of later word reading abilities and into the optimal time window to target a specific reading-related subskill during intervention.
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Affiliation(s)
- Lauren Blockmans
- Research Group ExpORL, Department of Neuroscience, KU Leuven, Leuven, Belgium
| | - Rogier Kievit
- Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, The Netherlands
| | - Jan Wouters
- Research Group ExpORL, Department of Neuroscience, KU Leuven, Leuven, Belgium
| | - Pol Ghesquière
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| | - Maaike Vandermosten
- Research Group ExpORL, Department of Neuroscience, KU Leuven, Leuven, Belgium
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3
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Wang Z, Zhao S, Zhang L, Yang Q, Cheng C, Ding N, Zhu Z, Shu H, Liu C, Zhao J. A genome-wide association study identifies a new variant associated with word reading fluency in Chinese children. GENES, BRAIN, AND BEHAVIOR 2023; 22:e12833. [PMID: 36514817 PMCID: PMC9994172 DOI: 10.1111/gbb.12833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 11/20/2022] [Accepted: 11/29/2022] [Indexed: 12/15/2022]
Abstract
Reading disability exhibited defects in different cognitive domains, including word reading fluency, word reading accuracy, phonological awareness, rapid automatized naming and morphological awareness. To identify the genetic basis of Chinese reading disability, we conducted a genome-wide association study (GWAS) of the cognitive traits related to Chinese reading disability in 2284 unrelated Chinese children. Among the traits analyzed in the present GWAS, we detected one genome-wide significant association (p < 5 × 10-8 ) on word reading fluency for one SNP on 4p16.2, within EVC genes (rs6446395, p = 7.33 × 10-10 ). Rs6446395 also showed significant association with Chinese character reading accuracy (p = 2.95 × 10-4 ), phonological awareness (p = 7.11 × 10-3 ) and rapid automatized naming (p = 4.71 × 10-3 ), implying multiple effects of this variant. The eQTL data showed that rs6446395 affected EVC expression in the cerebellum. Gene-based analyses identified a gene (PRDM10) to be associated with word reading fluency at the genome-wide level. Our study discovered a new candidate susceptibility variant for reading ability and provided new insights into the genetics of developmental dyslexia in Chinese children.
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Affiliation(s)
- Zhengjun Wang
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
| | - Shunan Zhao
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
| | - Liming Zhang
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
| | - Qing Yang
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
| | - Chen Cheng
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
| | - Ning Ding
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
| | - Zijian Zhu
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
| | - Hua Shu
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Chunyu Liu
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China.,The School of Life Sciences, Central South University, Changsha, China.,Department of Psychiatry, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jingjing Zhao
- School of Psychology, Shaanxi Normal University and Shaanxi Provincial Key Research Center of Child Mental and Behavioral Health, Xi'an, China
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4
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Courtright-Lim A. "CRISPR for Disabilities: How to Self-Regulate" or Something? JOURNAL OF BIOETHICAL INQUIRY 2022; 19:151-161. [PMID: 35362932 PMCID: PMC9007770 DOI: 10.1007/s11673-021-10162-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 04/24/2021] [Indexed: 05/24/2023]
Abstract
The development of the CRISPR gene editing technique has been hyped as a technique that could fundamentally change scientific research and its clinical application. Unrecognized is the fact that it joins other technologies that have tried and failed under the same discourse of scientific hype. These technologies, like gene therapy and stem cell research, have moved quickly passed basic research into clinical application with dire consequences. Before hastily moving to clinical applications, it is necessary to consider basic research and determine how CRISPR/Cas systems should be applied. In the case of single gene diseases, that application is expected to have positive impacts, but as we shift to more complex diseases, the impact could be unintentionally negative. In the context of common disabilities, the level of genetic complexity may render this technology useless but potentially toxic, aggravating a social discourse that devalues those with disabilities. This paper intends to define the issues related to disability that are associated with using the CRIPSR/Cas system in basic research. It also aims to provide a decision tree to help determine whether the technology should be utilized or if alternative approaches beyond scientific research could lead to a better use of limited funding resources.
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Affiliation(s)
- Amanda Courtright-Lim
- Cardiff University, Cardiff, Wales, CF10 3AT, UK.
- Translational Genomic Research Institute, 445 N. 5th Street, Phoenix, AZ, 85004, USA.
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5
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Helland T, Morken F, Helland WA. Kindergarten screening tools filled out by parents and teachers targeting dyslexia. Predictions and developmental trajectories from age 5 to age 15 years. DYSLEXIA (CHICHESTER, ENGLAND) 2021; 27:413-435. [PMID: 34585461 DOI: 10.1002/dys.1698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 07/21/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
The concept of early 'efforts' has led to discussions for and against introducing language assessment for all kindergarten children. Evidence-based kindergarten screening tools completed by close caregivers could solve this controversy as the children themselves would only be indirectly involved. The aim of this study was to see whether the scores of such early screening tools aiming at developmental dyslexia could predict school marks of literacy competence 10 years later, and to see whether these screening tools would reveal different dyslexia trajectories. The study is part of the Bergen Longitudinal Dyslexia Study, and the results from individual testing are reported elsewhere. Here, the caregivers' views isolated from the rest of the study are focused. Three tools were used: the RI-5, a questionnaire assessing the risk of dyslexia; the TRAS, a non-standardized observation tool of children's communication skills; and the CCC-2, a questionnaire assessing Developmental Language Disorders. Screening was performed at age 5 (TP1), age 11, (TP2) and age 15 (TP3). At TP2, when dyslexia was identified, 13 children formed the dyslexia group, and the rest formed the control group. At TP3, the RI-5 and CCC-2 turned out to be predictive of literacy competence as measured by school marks. Developmental trajectories were seen through the regroupings and scorings into a persistent group, a late onset group and a resolving group. Evidence-based preschool screening tools filled out by close caregivers offer valid information on later literacy developmental trajectories.
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Affiliation(s)
- Turid Helland
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - Frøydis Morken
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - Wenche A Helland
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
- Department of Research and Innovation, Helse Fonna Health Authority, Norway Helse Fonna HF, Haugesund, Norway
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Hamilton LG, Hayiou‐Thomas ME, Snowling MJ. Shared storybook reading with children at family risk of dyslexia. JOURNAL OF RESEARCH IN READING 2021; 44:859-881. [PMID: 35368878 PMCID: PMC8940243 DOI: 10.1111/1467-9817.12375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 07/20/2021] [Accepted: 07/27/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Shared storybook reading is an important context for language learning and often constitutes young children's first encounter with the printed word. The quality of early shared reading interactions is a known predictor of language and reading development, but few studies have examined these interactions in children at family risk of dyslexia. METHODS This exploratory study describes the quality of shared storybook reading between mothers and their 3- to 4-year-old children at family risk of dyslexia (FR; n = 18) in comparison with dyads with no known risk (no-FR; n = 13). Mother-child interactions while sharing a familiar and an unfamiliar storybook were coded for type of extra-textual talk (meaning-related talk at the concrete and abstract levels; print-related talk) and affective quality. Maternal and child language and literacy skills were considered as potential correlates of shared reading quality. RESULTS The linguistic and affective quality of shared reading was broadly comparable across FR and no-FR dyads, particularly when sharing a book they knew well, with large within-group variation. Mothers contributed more concrete meaning-related talk when introducing an unfamiliar book to their children; children contributed more extra-textual talk overall when sharing a familiar book. Maternal language, but not reading, skills were related to the linguistic quality of shared reading. The affective quality of reading interactions was rated more highly in dyads where mothers and children had stronger language skills. CONCLUSIONS These results suggest that the quality of shared reading does not vary systematically as a function of children's risk of dyslexia but is related to maternal language skills. This finding needs to be replicated in a larger sample in order to better understand the risk and protective factors associated with dyslexia. HIGHLIGHTS What is already known about this topic The quality of extra-textual talk during shared reading between parents and preschoolers predicts later language and literacy outcomes in typically developing children.The affective quality of early shared reading predicts children's motivation to read independently in later childhood.Children at family risk of dyslexia are more likely than their peers with no family risk to have difficulty learning to read and may show weaknesses in oral language skills. What this paper adds The linguistic and affective quality of shared reading between mothers and preschool children is broadly similar when children are at family risk of dyslexia compared with no family risk.The type and quantity of extra-textual talk contributed by mothers and children appears to differ according to the familiarity of the storybook, but replication of the findings in a larger sample is required.The linguistic and affective quality of shared reading is related to maternal language skills. Implications for theory, policy or practice Shared storybook reading offers rich language learning opportunities for children at family risk of dyslexia.Maternal language skills may be an important determinant of the interactional quality of shared reading.The linguistic and affective quality of shared reading is not clearly associated with maternal reading difficulties.
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Affiliation(s)
- Lorna G. Hamilton
- School of Education, Language and PsychologyYork St John UniversityYorkUK
| | | | - Margaret J. Snowling
- Department of Experimental Psychology and St John's CollegeUniversity of OxfordOxfordUK
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7
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Developmental Dyslexia: Environment Matters. Brain Sci 2021; 11:brainsci11060782. [PMID: 34199166 PMCID: PMC8231524 DOI: 10.3390/brainsci11060782] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 12/15/2022] Open
Abstract
Developmental dyslexia (DD) is a multifactorial, specific learning disorder. Susceptibility genes have been identified, but there is growing evidence that environmental factors, and especially stress, may act as triggering factors that determine an individual's risk of developing DD. In DD, as in most complex phenotypes, the presence of a genetic mutation fails to explain the broad phenotypic spectrum observed. Early life stress has been repeatedly associated with the risk of multifactorial disorders, due to its effects on chromatin regulation, gene expression, HPA axis function and its long-term effects on the systemic stress response. Based on recent evidence, we discuss the potential role of stress on DD occurrence, its putative epigenetic effects on the HPA axis of affected individuals, as well as the necessity of early and appropriate intervention, based on the individual stress-associated (endo)phenotype.
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8
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Whole-genome sequencing identifies functional noncoding variation in SEMA3C that cosegregates with dyslexia in a multigenerational family. Hum Genet 2021; 140:1183-1200. [PMID: 34076780 PMCID: PMC8263547 DOI: 10.1007/s00439-021-02289-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 04/27/2021] [Indexed: 12/11/2022]
Abstract
Dyslexia is a common heritable developmental disorder involving impaired reading abilities. Its genetic underpinnings are thought to be complex and heterogeneous, involving common and rare genetic variation. Multigenerational families segregating apparent monogenic forms of language-related disorders can provide useful entrypoints into biological pathways. In the present study, we performed a genome-wide linkage scan in a three-generational family in which dyslexia affects 14 of its 30 members and seems to be transmitted with an autosomal dominant pattern of inheritance. We identified a locus on chromosome 7q21.11 which cosegregated with dyslexia status, with the exception of two cases of phenocopy (LOD = 2.83). Whole-genome sequencing of key individuals enabled the assessment of coding and noncoding variation in the family. Two rare single-nucleotide variants (rs144517871 and rs143835534) within the first intron of the SEMA3C gene cosegregated with the 7q21.11 risk haplotype. In silico characterization of these two variants predicted effects on gene regulation, which we functionally validated for rs144517871 in human cell lines using luciferase reporter assays. SEMA3C encodes a secreted protein that acts as a guidance cue in several processes, including cortical neuronal migration and cellular polarization. We hypothesize that these intronic variants could have a cis-regulatory effect on SEMA3C expression, making a contribution to dyslexia susceptibility in this family.
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9
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Snowling MJ, Hulme C. Annual Research Review: Reading disorders revisited - the critical importance of oral language. J Child Psychol Psychiatry 2021; 62:635-653. [PMID: 32956509 DOI: 10.1111/jcpp.13324] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/24/2020] [Accepted: 08/11/2020] [Indexed: 02/06/2023]
Abstract
This paper discusses research on reading disorders during the period since their classification within the overarching category of neurodevelopmental disorders (Journal of Child Psychology and Psychiatry, 53, 2012, 593). Following a review of the predictors of learning to read across languages, and the role of language skills as critical foundations for literacy, profiles of reading disorders are discussed and putative causal risk factors at the cognitive, biological, and environmental levels of explanation considered. Reading disorders are highly heritable and highly comorbid with disorders of language, attention, and other learning disorders, notably mathematics disorders. The home literacy environment, reflecting gene-environment correlation, is one of several factors that promote reading development and highlight an important target for intervention. The multiple deficit view of dyslexia (Cognition, 101, 2006, 385) suggests that risks accumulate to a diagnostic threshold although categorical diagnoses tend to be unstable. Implications for assessment and intervention are discussed.
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Affiliation(s)
- Margaret J Snowling
- Department of Experimental Psychology, University of Oxford, Oxford, UK.,St John's College, University of Oxford, Oxford, UK
| | - Charles Hulme
- Department of Education, University of Oxford, Oxford, UK
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10
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The heritability of reading and reading-related neurocognitive components: A multi-level meta-analysis. Neurosci Biobehav Rev 2020; 121:175-200. [PMID: 33246020 DOI: 10.1016/j.neubiorev.2020.11.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 11/13/2020] [Accepted: 11/19/2020] [Indexed: 01/25/2023]
Abstract
Reading ability is a complex task requiring the integration of multiple cognitive and perceptual systems supporting language, visual and orthographic processes, working memory, attention, motor movements, and higher-level comprehension and cognition. Estimates of genetic and environmental influences for some of these reading-related neurocognitive components vary across reports. By using a multi-level meta-analysis approach, we synthesized the results of behavioral genetic research on reading-related neurocognitive components (i.e. general reading, letter-word knowledge, phonological decoding, reading comprehension, spelling, phonological awareness, rapid automatized naming, and language) of 49 twin studies spanning 4.1-18.5 years of age, with a total sample size of more than 38,000 individuals. Except for language for which shared environment seems to play a more important role, the causal architecture across most of the reading-related neurocognitive components can be represented by the following equation a² > e² > c². Moderators analysis revealed that sex and spoken language did not affect the heritability of any reading-related skills; school grade levels moderated the heritability of general reading, reading comprehension and phonological awareness.
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11
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Nishiyama KV, Satta Y, Gojobori J. Do Genes Associated with Dyslexia of Chinese Characters Evolve Neutrally? Genes (Basel) 2020; 11:genes11060658. [PMID: 32560373 PMCID: PMC7349701 DOI: 10.3390/genes11060658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/13/2020] [Accepted: 06/13/2020] [Indexed: 12/29/2022] Open
Abstract
Dyslexia, or reading disability, is found to have a genetic basis, and several related genes have been reported. We investigated whether natural selection has acted on single nucleotide polymorphisms (SNPs) that were reported to be associated with risk/non-risk for the reading disability of Chinese characters. We applied recently developed 2D SFS-based statistics to SNP data of East Asian populations to examine whether there is any sign of selective sweep. While neutrality was not rejected for most SNPs, significant signs of selection were detected for two linkage disequilibrium (LD) regions containing the reported SNPs of GNPTAB and DCDC2. Furthermore, we searched for a selection target site among the SNPs in these LD regions, because a causal site is not necessarily a reported SNP but could instead be a tightly linked site. In both LD regions, we found candidate target sites, which may have an effect on expression regulation and have been selected, although which genes these SNPs affect remains unknown. Because most people were not engaged in reading until recently, it is unlikely that there has been selective pressure on reading ability itself. Consistent with this, our results suggest a possibility of genetic hitchhiking, whereby alleles of the reported SNPs may have increased in frequency together with the selected target, which could have functions for other genes and traits apart from reading ability.
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12
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Caldani S, Gerard CL, Peyre H, Bucci MP. Pursuit eye movements in dyslexic children: evidence for an immaturity of brain oculomotor structures? J Eye Mov Res 2020; 13. [PMID: 33828780 PMCID: PMC7881873 DOI: 10.16910/jemr.13.1.5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Background: Dyslexia is a disorder found in 5-10% of school-aged children. Several studies reported visual deficits and oculomotor abnormalities in dyslexic children. The objective of our study was to examine horizontal pursuit performance in dyslexic children, despite its poor involvement in reading. Methods: Eye movements were recorded by video-oculography in 92 children (46 dyslexic children, mean age: 9.77 ± 0.26 and 46 non dyslexic, IQ- and age-matched children). Both the number of catch-up saccades occurring during pursuit task and the gain of pursuit were measured. Results: Catch-up saccades were significantly more frequent in the dyslexic group than in the non-dyslexic group of children. Pursuit performance (in terms of the number of catch-up saccades and gain) significantly improved with increasing age in the non-dyslexic children group only. Conclusions: The atypical pursuit patterns observed in dyslexic children suggest a deficiency in the visual attentional processing and an immaturity of brain structures responsible for pursuit triggering. This finding needs to be validated by neuroimaging studies on dyslexia population.
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13
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The Association of Dyslexia and Developmental Speech and Language Disorder Candidate Genes with Reading and Language Abilities in Adults. Twin Res Hum Genet 2020; 23:23-32. [PMID: 32248883 DOI: 10.1017/thg.2020.7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Reading and language abilities are critical for educational achievement and success in adulthood. Variation in these traits is highly heritable, but the underlying genetic architecture is largely undiscovered. Genetic studies of reading and language skills traditionally focus on children with developmental disorders; however, much larger unselected adult samples are available, increasing power to identify associations with specific genetic variants of small effect size. We introduce an Australian adult population cohort (41.7-73.2 years of age, N = 1505) in which we obtained data using validated measures of several aspects of reading and language abilities. We performed genetic association analysis for a reading and spelling composite score, nonword reading (assessing phonological processing: a core component in learning to read), phonetic spelling, self-reported reading impairment and nonword repetition (a marker of language ability). Given the limited power in a sample of this size (~80% power to find a minimum effect size of 0.005), we focused on analyzing candidate genes that have been associated with dyslexia and developmental speech and language disorders in prior studies. In gene-based tests, FOXP2, a gene implicated in speech/language disorders, was associated with nonword repetition (p < .001), phonetic spelling (p = .002) and the reading and spelling composite score (p < .001). Gene-set analyses of candidate dyslexia and speech/language disorder genes were not significant. These findings contribute to the assessment of genetic associations in reading and language disorders, crucial for understanding their etiology and informing intervention strategies, and validate the approach of using unselected adult samples for gene discovery in language and reading.
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14
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Ladányi E, Persici V, Fiveash A, Tillmann B, Gordon RL. Is atypical rhythm a risk factor for developmental speech and language disorders? WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2020; 11:e1528. [PMID: 32244259 PMCID: PMC7415602 DOI: 10.1002/wcs.1528] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 01/07/2023]
Abstract
Although a growing literature points to substantial variation in speech/language abilities related to individual differences in musical abilities, mainstream models of communication sciences and disorders have not yet incorporated these individual differences into childhood speech/language development. This article reviews three sources of evidence in a comprehensive body of research aligning with three main themes: (a) associations between musical rhythm and speech/language processing, (b) musical rhythm in children with developmental speech/language disorders and common comorbid attentional and motor disorders, and (c) individual differences in mechanisms underlying rhythm processing in infants and their relationship with later speech/language development. In light of converging evidence on associations between musical rhythm and speech/language processing, we propose the Atypical Rhythm Risk Hypothesis, which posits that individuals with atypical rhythm are at higher risk for developmental speech/language disorders. The hypothesis is framed within the larger epidemiological literature in which recent methodological advances allow for large-scale testing of shared underlying biology across clinically distinct disorders. A series of predictions for future work testing the Atypical Rhythm Risk Hypothesis are outlined. We suggest that if a significant body of evidence is found to support this hypothesis, we can envision new risk factor models that incorporate atypical rhythm to predict the risk of developing speech/language disorders. Given the high prevalence of speech/language disorders in the population and the negative long-term social and economic consequences of gaps in identifying children at-risk, these new lines of research could potentially positively impact access to early identification and treatment. This article is categorized under: Linguistics > Language in Mind and Brain Neuroscience > Development Linguistics > Language Acquisition.
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Affiliation(s)
- Enikő Ladányi
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Valentina Persici
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Psychology, Università degli Studi di Milano - Bicocca, Milan, Italy.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Anna Fiveash
- Lyon Neuroscience Research Center, Auditory Cognition and Psychoacoustics Team, CRNL, INSERM, University of Lyon 1, U1028, CNRS, UMR5292, Lyon, France
| | - Barbara Tillmann
- Lyon Neuroscience Research Center, Auditory Cognition and Psychoacoustics Team, CRNL, INSERM, University of Lyon 1, U1028, CNRS, UMR5292, Lyon, France
| | - Reyna L Gordon
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Genetics Institute, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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15
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Peyre H, Mohanpuria N, Jednoróg K, Heim S, Grande M, van Ermingen-Marbach M, Altarelli I, Monzalvo K, Williams CM, Germanaud D, Toro R, Ramus F. Neuroanatomy of dyslexia: An allometric approach. Eur J Neurosci 2020; 52:3595-3609. [PMID: 31991019 DOI: 10.1111/ejn.14690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/04/2020] [Accepted: 01/17/2020] [Indexed: 01/06/2023]
Abstract
Despite evidence for a difference in total brain volume between dyslexic and good readers, no previous neuroimaging study examined differences in allometric scaling (i.e. differences in the relationship between regional and total brain volumes) between dyslexic and good readers. The present study aims to fill this gap by testing differences in allometric scaling and regional brain volume differences in dyslexic and good readers. Object-based morphometry analysis was used to determine grey and white matter volumes of the four lobes, the cerebellum and limbic structures in 130 dyslexic and 106 good readers aged 8-14 years. Data were collected across three countries (France, Poland and Germany). Three methodological approaches were used as follows: principal component analysis (PCA), linear regression and multiple-group confirmatory factor analysis (MGCFA). Difference in total brain volume between good and dyslexic readers was Cohen's d = 0.39. We found no difference in allometric scaling, nor in regional brain volume between dyslexic and good readers. Results of our three methodological approaches (PCA, linear regression and MGCFA) were consistent. This study provides evidence for total brain volume differences between dyslexic and control children, but no evidence for differences in the volumes of the four lobes, the cerebellum or limbic structures, once allometry is taken into account. It also finds no evidence for a difference in allometric relationships between the groups. We highlight the methodological interest of the MGCFA approach to investigate such research issues.
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Affiliation(s)
- Hugo Peyre
- Laboratoire de Sciences Cognitives et Psycholinguistique (ENS, EHESS, CNRS), Ecole Normale Supérieure, PSL University, Paris, France.,Neurodiderot, INSERM UMR 1141, Paris Diderot University, Paris, France.,Department of Child and Adolescent Psychiatry, Robert Debré Hospital, APHP, Paris, France
| | - Neha Mohanpuria
- Laboratoire de Sciences Cognitives et Psycholinguistique (ENS, EHESS, CNRS), Ecole Normale Supérieure, PSL University, Paris, France
| | - Katarzyna Jednoróg
- Laboratory of Language Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences (PAS), Warsaw, Poland
| | - Stefan Heim
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Institute of Neuroscience and Medicine (INM-1), Helmholtz-Gemeinschaft Deutscher Forschungszentren (HZ), Jülich, Germany
| | - Marion Grande
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Muna van Ermingen-Marbach
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Irene Altarelli
- Laboratory for the Psychology of Child Development and Education, CNRS UMR 8240, Université de Paris, Paris, France
| | - Karla Monzalvo
- INSERM, UMR992, CEA, NeuroSpin Center, University Paris Saclay, Gif-sur-Yvette, France
| | - Camille Michèle Williams
- Laboratoire de Sciences Cognitives et Psycholinguistique (ENS, EHESS, CNRS), Ecole Normale Supérieure, PSL University, Paris, France
| | - David Germanaud
- Neurodiderot, INSERM UMR 1141, Paris Diderot University, Paris, France.,INSERM, UMR992, CEA, NeuroSpin Center, University Paris Saclay, Gif-sur-Yvette, France.,Department of Pediatric Neurology and Metabolic Diseases, Robert Debré Hospital, APHP, Paris, France.,INSERM, CEA, UMR 1129, Sorbonne Paris Cité University (USPC), Paris, France
| | - Roberto Toro
- Human Genetics and Cognitive Functions, Institut Pasteur, Paris, France
| | - Franck Ramus
- Laboratoire de Sciences Cognitives et Psycholinguistique (ENS, EHESS, CNRS), Ecole Normale Supérieure, PSL University, Paris, France
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16
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Protopapas A. Evolving Concepts of Dyslexia and Their Implications for Research and Remediation. Front Psychol 2019; 10:2873. [PMID: 31920890 PMCID: PMC6930188 DOI: 10.3389/fpsyg.2019.02873] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 12/04/2019] [Indexed: 11/13/2022] Open
Abstract
Aspects of dyslexia definitions are framed as a contrast between the past and the future, focusing on implications for research and remedial education, highlighting assumptions that bias or limit research or clinical practice. A crucial development is evident in understanding dyslexia, moving from its conceptualization as a discrete identifiable condition toward the realization of continuity with the general population with no clear boundaries and no qualitative differences. This conceptual evolution amounts to a transition from considering dyslexia to be some entity that causes poor reading toward considering the term dyslexia to simply label poor reading performance. This renders obsolete any searches for abnormalities and directs efforts toward understanding reading skill as a multifaceted domain following a complex multifactorial developmental course.
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17
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Del Tufo SN, Earle FS, Cutting LE. The impact of expressive language development and the left inferior longitudinal fasciculus on listening and reading comprehension. J Neurodev Disord 2019; 11:37. [PMID: 31838999 PMCID: PMC6912995 DOI: 10.1186/s11689-019-9296-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/11/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND During the first 3-years of life, as the brain undergoes dramatic growth, children begin to develop speech and language. Hallmarks of this progression are seen when children reach developmental milestones, forming the foundation of language. Expressive language milestones, such as the production of a child's first word, are delayed in 5-8% of children. While for some children delays in reaching these milestones are harbingers of developmental disorders, for others expressive language delays appear to resolve. Regardless of whether or not early language skills appear resolved, difficulty with later comprehension is a likely outcome. Whether this heightened risk for poor comprehension differs based on text features, individual characteristics, or receipt of intervention remains unknown. Moreover, this relationship between expressive language development and comprehension is not yet linked to neurobiology, though the inferior longitudinal fasciculus (ILF) is a potential neurobiological correlate. Therefore, we investigated the impact of, and interactions between, expressive language development, early intervention, and the ILF on comprehension. METHODS Longitudinal recurrent survival analyses predicted the risk of answering a comprehension question incorrectly. Predictors of comprehension included expressive language development, passage features, participant characteristics, fractional anisotropy, receipt of early intervention, and later diagnosis of speech or language disorders. RESULTS Children with later expressive language milestones had poorer comprehension. When comprehension text features were examined, children with later milestones had poorer listening and reading comprehension, and poorer narrative and expository comprehension. The left ILF acted as a neurodevelopmental correlate, one that moderated the relationship between expressive language milestones and comprehension. Specifically, the left ILF exacerbated the relationship for those who did not receive early intervention and buffered the relationship for those who received intervention services. Early intervention decreased the risk of poor comprehension by 39% for children later diagnosed with a speech or language disorder. CONCLUSIONS Early intervention should be provided for children with delayed expressive language milestones, particularly those who are at risk for speech or language disorders. The ILF plays a critical role in the relationship between expressive language development and comprehension, which may be that of a protective factor for children with the most severe early issues with speech and language.
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Affiliation(s)
- Stephanie N Del Tufo
- Peabody College of Education and Human Development, Vanderbilt University, 416C One Magnolia Circle, Box 228, Nashville, TN, 37203, USA.,Vanderbilt Brain Institute, Vanderbilt University School of Medicine, 6133 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, USA.,Vanderbilt Kennedy Center, Vanderbilt University, 110 Magnolia Circle, Nashville, TN, 37203, USA.,College of Education and Human Development, University of Delaware, 106 Alison Hall West, Newark, DE, 19716, USA
| | - F Sayako Earle
- Communication Sciences and Disorders, University of Delaware, 100 Discovery Boulevard, Newark, DE, 19713, USA
| | - Laurie E Cutting
- Peabody College of Education and Human Development, Vanderbilt University, 416C One Magnolia Circle, Box 228, Nashville, TN, 37203, USA. .,Vanderbilt Brain Institute, Vanderbilt University School of Medicine, 6133 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, USA. .,Vanderbilt Kennedy Center, Vanderbilt University, 110 Magnolia Circle, Nashville, TN, 37203, USA.
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18
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Bucci MP. Visual training could be useful for improving reading capabilities in dyslexia. APPLIED NEUROPSYCHOLOGY-CHILD 2019; 10:199-208. [PMID: 31407599 DOI: 10.1080/21622965.2019.1646649] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The term dyslexia originated in 1887 when an ophthalmologist described the difficulty of learning to read. After more than a century of research, we still do not know the etiology of such pathology. Several hypotheses have been suggested to explain dyslexia and in the present article we will describe in detail the visual attentional deficits reported in dyslexia. Reading is a complex cognitive process during which several mechanisms are involved (visual perception, eye movements -saccades and fixations-, semantic and linguistic abilities); consequently, a deficit in one of these different components could cause impairment in reading acquisition. In children with dyslexia, we observed abnormal oculomotor patterns during reading: frequent saccades of small amplitude, long-term fixation, high number of saccades to the left (retro-saccades), and poor binocular coordination during and after the saccades. These results suggest a deficit of visual information processing as well as an immaturity of the interaction between the saccade and vergence systems. In the present review, we will discuss different methods that use short periods of visual rehabilitation or text manipulation, and by using an eye tracker in order to obtain objective information on eye movement's performance during reading, assist in improved reading performance of dyslexic children.
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Affiliation(s)
- Maria Pia Bucci
- UMR 1141 Inserm - Paris Diderot University, Robert Debré Hospital, Paris, France
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19
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Peters L, Ansari D. Are specific learning disorders truly specific, and are they disorders? Trends Neurosci Educ 2019; 17:100115. [PMID: 31685130 DOI: 10.1016/j.tine.2019.100115] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 05/30/2019] [Accepted: 07/05/2019] [Indexed: 12/12/2022]
Abstract
Specific learning disorders, such as dyslexia and dyscalculia, are frequently studied to inform our understanding of cognitive development, genetic mechanisms and brain function. In this Opinion Paper, we discuss limitations of this research approach, including the use of arbitrary criteria to select groups of children, heterogeneity within groups and overlap between domains of learning. By drawing on evidence from cognitive science, neuroscience and genetics, we propose an alternative, dimensional framework. We argue that we need to overcome the problems associated with a categorical approach by taking into account interacting factors at multiple levels of analysis that are associated with overlapping rather than entirely distinct domains of learning. We conclude that this research strategy will allow for a richer understanding of learning and development.
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Affiliation(s)
- Lien Peters
- Numerical Cognition Laboratory, Department of Psychology, Faculty of Education & Brain and Mind Institute, University of Western Ontario, Western Interdisciplinary Research Building, 1151 Richmond Street North, London, ON N6A 5B7, Canada.
| | - Daniel Ansari
- Numerical Cognition Laboratory, Department of Psychology, Faculty of Education & Brain and Mind Institute, University of Western Ontario, Western Interdisciplinary Research Building, 1151 Richmond Street North, London, ON N6A 5B7, Canada
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20
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D'Mello AM, Gabrieli JDE. Cognitive Neuroscience of Dyslexia. Lang Speech Hear Serv Sch 2019; 49:798-809. [PMID: 30458541 DOI: 10.1044/2018_lshss-dyslc-18-0020] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/08/2018] [Indexed: 01/16/2023] Open
Abstract
Purpose This review summarizes what is known about the structural and functional brain bases of dyslexia. Method We review the current literature on structural and functional brain differences in dyslexia. This includes evidence about differences in gray matter anatomy, white matter connectivity, and functional activations in response to print and language. We also summarize findings concerning brain plasticity in response to interventions. Results We highlight evidence relating brain function and structure to instructional issues such as diagnosis and prognosis. We also highlight evidence about brain differences in early childhood, before formal reading instruction in school, which supports the importance of early identification and intervention. Conclusion Neuroimaging studies of dyslexia reveal how the disorder is related to differences in structure and function in multiple neural circuits.
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Affiliation(s)
- Anila M D'Mello
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge
| | - John D E Gabrieli
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge
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21
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Same or Different: The Overlap Between Children With Auditory Processing Disorders and Children With Other Developmental Disorders: A Systematic Review. Ear Hear 2019; 39:1-19. [PMID: 28863035 PMCID: PMC7654752 DOI: 10.1097/aud.0000000000000479] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Supplemental Digital Content is available in the text. Objectives: Children diagnosed with auditory processing disorders (APD) experience difficulties in auditory functioning and with memory, attention, language, and reading tasks. However, it is not clear whether the behavioral characteristics of these children are distinctive from the behavioral characteristics of children diagnosed with a different developmental disorder, such as specific language impairment (SLI), dyslexia, attention-deficit hyperactivity disorder (ADHD), learning disorder (LD), or autism spectrum disorder. This study describes the performance of children diagnosed with APD, SLI, dyslexia, ADHD, and LD to different outcome measurements. The aim of this study was to determine (1) which characteristics of APD overlap with the characteristics of children with SLI, dyslexia, ADHD, LD, or autism spectrum disorder; and (2) if there are characteristics that distinguish children diagnosed with APD from children diagnosed with other developmental disorders. Design: A systematic review. Six electronic databases (Pubmed, CINAHL, Eric, PsychINFO, Communication & Mass Media Complete, and EMBASE) were searched to find peer-reviewed studies from 1954 to May 2015. The authors included studies reporting behaviors and performance of children with (suspected) APD and children diagnosed with a different developmental disorder (SLI, Dyslexia, ADHD, and LD). Two researchers identified and screened the studies independently. Methodological quality of the included studies was assessed with the American Speech-Language-Hearing Association’s levels-of-evidence scheme. Results: In total, 13 studies of which the methodological quality was moderate were included in this systematic review. In five studies, the performance of children diagnosed with APD was compared with the performance of children diagnosed with SLI: in two with children diagnosed with dyslexia, one with children diagnosed with ADHD, and in another one with children diagnosed with LD. Ten of the studies included children who met the criteria for more than one diagnosis. In four studies, there was a comparison made between the performances of children with comorbid disorders. There were no studies found in which the performance of children diagnosed with APD was compared with the performance of children diagnosed with autism spectrum disorder. Children diagnosed with APD broadly share the same characteristics as children diagnosed with other developmental disorders, with only minor differences between them. Differences were determined with the auditory and visual Duration Pattern Test, the Children’s Auditory Processing Performance Scale questionnaire, and the subtests of the Listening in Spatialized Noise-Sentences test, in which noise is spatially separated from target sentences. However, these differences are not consistent between studies and are not found in comparison to all groups of children with other developmental disorders. Conclusions: Children diagnosed with APD perform equally to children diagnosed with SLI, dyslexia, ADHD, and LD on tests of intelligence, memory or attention, and language tests. Only small differences between groups were found for sensory and perceptual functioning tasks (auditory and visual). In addition, children diagnosed with dyslexia performed poorer in reading tasks compared with children diagnosed with APD. The result is possibly confounded by poor quality of the research studies and the low quality of the used outcome measures. More research with higher scientific rigor is required to better understand the differences and similarities in children with various neurodevelopmental disorders.
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22
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Saffran JR. Statistical learning as a window into developmental disabilities. J Neurodev Disord 2018; 10:35. [PMID: 30541453 PMCID: PMC6292000 DOI: 10.1186/s11689-018-9252-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 11/14/2018] [Indexed: 01/30/2023] Open
Abstract
Until recently, most behavioral studies of children with intellectual and developmental disabilities (IDD) have used standardized assessments as a means to probe etiology and to characterize phenotypes. Over the past decade, however, tasks originally developed to investigate learning processes in typical development have been brought to bear on developmental processes in children with IDD. This brief review will focus on one learning process in particular—statistical learning—and will provide an overview of what has been learned thus far from studies using statistical learning tasks with different groups of children with IDD conditions. While a full picture is not yet available, results to date suggest that studies of learning are both feasible and informative about learning processes that may differ across diagnostic groups, particularly as they relate to language acquisition. More generally, studies focused on learning processes may be highly informative about different developmental trajectories both across groups and within groups of children.
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Affiliation(s)
- Jenny R Saffran
- Waisman Center, University of Wisconsin-Madison, 1500 Highland Ave, Madison, WI, 53705, USA.
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23
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Guidi LG, Velayos‐Baeza A, Martinez‐Garay I, Monaco AP, Paracchini S, Bishop DVM, Molnár Z. The neuronal migration hypothesis of dyslexia: A critical evaluation 30 years on. Eur J Neurosci 2018; 48:3212-3233. [PMID: 30218584 PMCID: PMC6282621 DOI: 10.1111/ejn.14149] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/06/2018] [Accepted: 08/13/2018] [Indexed: 12/29/2022]
Abstract
The capacity for language is one of the key features underlying the complexity of human cognition and its evolution. However, little is known about the neurobiological mechanisms that mediate normal or impaired linguistic ability. For developmental dyslexia, early postmortem studies conducted in the 1980s linked the disorder to subtle defects in the migration of neurons in the developing neocortex. These early studies were reinforced by human genetic analyses that identified dyslexia susceptibility genes and subsequent evidence of their involvement in neuronal migration. In this review, we examine recent experimental evidence that does not support the link between dyslexia and neuronal migration. We critically evaluate gene function studies conducted in rodent models and draw attention to the lack of robust evidence from histopathological and imaging studies in humans. Our review suggests that the neuronal migration hypothesis of dyslexia should be reconsidered, and the neurobiological basis of dyslexia should be approached with a fresh start.
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Affiliation(s)
- Luiz G. Guidi
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Antonio Velayos‐Baeza
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Isabel Martinez‐Garay
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Division of NeuroscienceSchool of BiosciencesCardiff UniversityCardiffUK
| | | | | | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
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24
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Mascheretti S, Andreola C, Scaini S, Sulpizio S. Beyond genes: A systematic review of environmental risk factors in specific reading disorder. RESEARCH IN DEVELOPMENTAL DISABILITIES 2018; 82:147-152. [PMID: 29566979 DOI: 10.1016/j.ridd.2018.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 03/10/2018] [Accepted: 03/11/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND While an understanding of the genetic contributions to specific reading disorder (RD) is emerging, there is no agreement about which putative hazard factors are clearly involved in the aetiology of this disorder. AIMS A literature review looking at the impact of environmental risk variables implicated in RD either per se or when interacting with the genes. METHODS AND PROCEDURES We performed a systematic literature review using the following keywords: dyslexia OR reading disability AND environmental risk factors OR environmental hazard factors, in the following electronic databases: PubMed, Scopus and PsycINFO, without any time restrictions. OUTCOMES AND RESULTS Gestational weeks and birth weight are among the pre- and peri-natal risk factors shown to reliably predict reading readiness and the odds of having RD. Inconclusive findings have been reported for maternal cigarette smoking, family history of psychiatric and medical diseases, and risk of miscarriage. A broad definition of familial socio-economic status and home literacy environment have been identified as good life-long risk predictors of reading skills. CONCLUSIONS AND IMPLICATIONS We highlighted the need to consider environmental hazards, their interactions and interactions with RD-candidate genes in the study of the aetiology of RD in order to provide much-needed insight into how these variables influence reading skills.
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Affiliation(s)
- Sara Mascheretti
- Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Chiara Andreola
- Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Italy
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25
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Colenbrander D, Ricketts J, Breadmore HL. Early Identification of Dyslexia: Understanding the Issues. Lang Speech Hear Serv Sch 2018; 49:817-828. [DOI: 10.1044/2018_lshss-dyslc-18-0007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 06/05/2018] [Indexed: 11/09/2022] Open
Abstract
Purpose
The purpose of this tutorial is to provide an overview of the benefits and challenges associated with the early identification of dyslexia.
Method
The literature on the early identification of dyslexia is reviewed. Theoretical arguments and research evidence are summarized. An overview of response to intervention as a method of early identification is provided, and the benefits and challenges associated with it are discussed. Finally, the role of speech-language pathologists in the early identification process is addressed.
Conclusions
Early identification of dyslexia is crucial to ensure that children are able to maximize their educational potential, and speech-language pathologists are well placed to play a role in this process. However, early identification alone is not sufficient—difficulties with reading may persist or become apparent later in schooling. Therefore, continuing progress monitoring and access to suitable intervention programs are essential.
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Affiliation(s)
- Danielle Colenbrander
- School of Experimental Psychology, University of Bristol, United Kingdom
- Department of Cognitive Science, ARC Centre of Excellence in Cognition and its Disorders (CCD), Macquarie University, Sydney, Australia
| | - Jessie Ricketts
- Department of Psychology, Royal Holloway University of London, Egham England
| | - Helen L. Breadmore
- Centre for Advances in Behavioural Science, Coventry University, England
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26
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Perdue MV, Mascheretti S, Kornilov SA, Jasińska KK, Ryherd K, Einar Mencl W, Frost SJ, Grigorenko EL, Pugh KR, Landi N. Common variation within the SETBP1 gene is associated with reading-related skills and patterns of functional neural activation. Neuropsychologia 2018; 130:44-51. [PMID: 30009840 DOI: 10.1016/j.neuropsychologia.2018.07.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 05/09/2018] [Accepted: 07/12/2018] [Indexed: 11/25/2022]
Abstract
Epidemiological population studies highlight the presence of substantial individual variability in reading skill, with approximately 5-10% of individuals characterized as having specific reading disability (SRD). Despite reported substantial heritability, typical for a complex trait, the specifics of the connections between reading and the genome are not understood. Recently, the SETBP1 gene has been implicated in several complex neurodevelopmental syndromes and disorders that impact language. Here, we examined the relationship between common polymorphisms in this gene, reading, and reading associated behaviors using data from an ongoing project on the genetic basis of SRD (n = 135). In addition, an exploratory analysis was conducted to examine the relationship between SETBP1 and brain activation using functional magnetic resonance imaging (fMRI; n = 73). Gene-based analyses revealed a significant association between SETBP1 and phonological working memory, with rs7230525 as the strongest associated single nucleotide polymorphism (SNP). fMRI analysis revealed that the rs7230525-T allele is associated with functional neural activation during reading and listening to words and pseudowords in the right inferior parietal lobule (IPL). These findings suggest that common genetic variation within SETBP1 is associated with reading behavior and reading-related brain activation patterns in the general population.
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Affiliation(s)
- Meaghan V Perdue
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA; Haskins Laboratories, New Haven, CT, USA
| | - Sara Mascheretti
- Child Psychopathology Unit, Scientific Institute, IRCCS E. Medea, Bosisio Parini, LC, Italy
| | - Sergey A Kornilov
- Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Kaja K Jasińska
- Haskins Laboratories, New Haven, CT, USA; Department of Linguistics and Cognitive Science, University of Delaware, Newark, DE, USA
| | - Kayleigh Ryherd
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA; Haskins Laboratories, New Haven, CT, USA
| | | | | | - Elena L Grigorenko
- Haskins Laboratories, New Haven, CT, USA; Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; St. Petersburg State University, Russia
| | - Kenneth R Pugh
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA; Haskins Laboratories, New Haven, CT, USA
| | - Nicole Landi
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA; Haskins Laboratories, New Haven, CT, USA.
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27
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The influence of DCDC2 risk genetic variants on reading: Testing main and haplotypic effects. Neuropsychologia 2018; 130:52-58. [PMID: 29803723 DOI: 10.1016/j.neuropsychologia.2018.05.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 04/17/2018] [Accepted: 05/23/2018] [Indexed: 12/28/2022]
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental heritable disorder. Among DD candidate genes, DCDC2 is one of the most replicated, with rs793862, READ1 and rs793842 likely contribute to phenotypic variability in reading (dis)ability. In this study, we tested the effects of these genetic variants on DD as a categorical trait and on quantitative reading-related measures in a sample of 555 Italian nuclear families with 930 offspring, of which 687 were diagnosed with DD. We conducted both single-marker and haplotype analyses, finding that the READ1-deletion was significantly associated with reading, whereas no significant haplotype associations were found. Our findings add further evidence to support the hypothesis of a DCDC2 contribution to inter-individual variation in distinct indicators of reading (dis)ability in transparent languages (i.e., reading accuracy and speed), suggesting a potential pleiotropic effect.
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28
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Abbott RD, Raskind WH, Matsushita M, Price ND, Richards T, Berninger VW. Patterns of biomarkers for three phenotype profiles of persisting specific learning disabilities during middle childhood and early adolescence: A preliminary study. BIOMARKERS AND GENES 2017; 1:103. [PMID: 30854516 PMCID: PMC6407889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Students without specific learning disabilities [SLDs] [n=18] and with one of three persisting SLDs in written language despite early and current specialized instruction-Dysgraphia [n=21], Dyslexia [n=40], or oral and written language learning disability OWL LD [n=14]- in grades 4 to 9 [N=56 boys, 38 girls] completed behavioral phenotyping assessment and gave a small blood or saliva sample. Molecular analyses informed by current cross-site research on gene candidates for learning disabilities identified associations between molecular genetic markers and the two defining behavioral phenotypes for each SLDs-WL; dysgraphia [impaired writing alphabet from memory for rs3743204 and sentence copying in best handwriting for rs79382 both in DYX1C1], dyslexia [impaired silent word reading/decoding rate for rs4535189 in DCDC2 and impaired spelling/encoding for rs374205 in DYX1C1], and OWL LD [impaired aural syntax comprehension for rs807701 and oral syntax construction for rs807701 both in DYX1C1]. Implications of these identified associations between molecular markers for alleles for different sites within two gene candidates [and mostly one] and hallmark phenotypes are discussed for translation science [application to practice] and neuroimaging that has identified contrasting brain bases for each of the three SLDs.
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Affiliation(s)
- Robert D. Abbott
- University of Washington, Quantitative Studies and Measurement, USA
| | - Wendy H. Raskind
- University of Washington, Medicine, USA,University of Washington, Psychiatry and Behavioral Sciences, USA
| | | | - Nathan D. Price
- Institute for Systems Biology, USA,University of Washington, Bioengineering, Computer Science & Engineering, Molecular & Cellular Biology, USA
| | - Todd Richards
- University of Washington, Integrated Brain Imaging Center and Radiology, USA
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Le Floch A, Ropars G. Left-right asymmetry of the Maxwell spot centroids in adults without and with dyslexia. Proc Biol Sci 2017; 284:20171380. [PMID: 29046375 PMCID: PMC5666095 DOI: 10.1098/rspb.2017.1380] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/22/2017] [Indexed: 12/12/2022] Open
Abstract
In human vision, the brain has to select one view of the world from our two eyes. However, the existence of a clear anatomical asymmetry providing an initial imbalance for normal neural development is still not understood. Using a so-called foveascope, we found that for a cohort of 30 normal adults, the two blue cone-free areas at the centre of the foveas are asymmetrical. The noise-stimulated afterimage dominant eye introduced here corresponds to the circular blue cone-free area, while the non-dominant eye corresponds to the diffuse and irregular elliptical outline. By contrast, we found that this asymmetry is absent or frustrated in a similar cohort of 30 adults with normal ocular status, but with dyslexia, i.e. with visual and phonological deficits. In this case, our results show that the two Maxwell centroid outlines are both circular but lead to an undetermined afterimage dominance with a coexistence of primary and mirror images. The interplay between the lack of asymmetry and the development in the neural maturation of the brain pathways suggests new implications in both fundamental and biomedical sciences.
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Affiliation(s)
- Albert Le Floch
- Laboratoire de Physique des Lasers, UFR SPM, Université de Rennes 1, 35042 Rennes, France
- Laboratoire d'Electronique Quantique et Chiralités, 20 Square Marcel Bouget, 35700 Rennes, France
- Université Bretagne Loire, 35044 Rennes, France
| | - Guy Ropars
- Laboratoire de Physique des Lasers, UFR SPM, Université de Rennes 1, 35042 Rennes, France
- Université Bretagne Loire, 35044 Rennes, France
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30
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Black JM, Xia Z, Hoeft F. Neurobiological Bases of Reading Disorder Part II: The Importance of Developmental Considerations in Typical and Atypical Reading. LANGUAGE AND LINGUISTICS COMPASS 2017; 11:e12252. [PMID: 29276529 PMCID: PMC5736136 DOI: 10.1111/lnc3.12252] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Decoding-based reading disorder (RD; aka developmental dyslexia) is one of the most common neurodevelopmental disorders, affecting approximately 5-10% of school-aged children across languages. Even though neuroimaging studies suggest an impairment of the left reading network in RD, the onset of this deficit and its developmental course, which may include constancy and change, is largely unknown. There is now growing evidence that the recruitment of brain networks underlying perceptual, cognitive and linguistic processes relevant to reading acquisition varies with age. These age-dependent changes may in turn impact the neurocognitive characteristics of RD observed at specific developmental stages. Here we synthesize findings from functional and structural magnetic resonance imaging (MRI) studies to increase our understanding of the developmental time course of the neural bases underlying (a)typical reading. We first provide an overview of the brain bases of typical and atypical (impaired) reading. Next we describe how the understanding of RD can be deepened through scientific attention to age effects, for example, by integrating findings from cross-sectional studies of RD at various ages. Finally, we accent findings from extant longitudinal studies that directly examine developmental reading trajectories beginning in the preliterate stage at both group and individual levels. Although science is at the very early stage of understanding developmental aspects of neural deficits in RD, evidence to date characterizes RD by atypical brain maturation. We know that reading impairment may adversely impact multiple life domains such as academic achievement and social relationships, and unfortunately, that these negative outcomes can persist and compound into adulthood. We contend that exploring the developmental trajectories of RD will contribute to a greater understanding of how neural systems support reading acquisition. Further, we propose and cite evidence that the etiology of RD can be better investigated by distinguishing primary deficits from secondary impairments unfolding along development. These exciting and modern investigatory efforts can also indirectly contribute to a centered practice of early and accurate identification and optimal intervention to support the development of foundational pre-literacy skills and fluent reading. In sum, integrating a developmental understanding into the science and practice of reading acquisition and intervention is both possible and necessary.
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Affiliation(s)
| | - Zhichao Xia
- Department of Psychiatry and Weill Institute for Neurosciences,
University of California, San Francisco (UCSF), USA
- State Key Laboratory of Cognitive Neuroscience and Learning
& IDG/McGovern Institute for Brain Research, Beijing Normal University,
China
- Center for Collaboration and Innovation in Brain and Learning
Sciences, Beijing Normal University, China
| | - Fumiko Hoeft
- Department of Psychiatry and Weill Institute for Neurosciences,
University of California, San Francisco (UCSF), USA
- Precision Learning Center (PrecL), UC, USA
- Dyslexia Center, UCSF, USA
- Haskins Laboratories, USA
- Department of Neuropsychiatry, Keio University School of Medicine,
Japan
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31
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Bishop DV, Snowling MJ, Thompson PA, Greenhalgh T. Phase 2 of CATALISE: a multinational and multidisciplinary Delphi consensus study of problems with language development: Terminology. J Child Psychol Psychiatry 2017; 58:1068-1080. [PMID: 28369935 PMCID: PMC5638113 DOI: 10.1111/jcpp.12721] [Citation(s) in RCA: 615] [Impact Index Per Article: 87.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/22/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Lack of agreement about criteria and terminology for children's language problems affects access to services as well as hindering research and practice. We report the second phase of a study using an online Delphi method to address these issues. In the first phase, we focused on criteria for language disorder. Here we consider terminology. METHODS The Delphi method is an iterative process in which an initial set of statements is rated by a panel of experts, who then have the opportunity to view anonymised ratings from other panel members. On this basis they can either revise their views or make a case for their position. The statements are then revised based on panel feedback, and again rated by and commented on by the panel. In this study, feedback from a second round was used to prepare a final set of statements in narrative form. The panel included 57 individuals representing a range of professions and nationalities. RESULTS We achieved at least 78% agreement for 19 of 21 statements within two rounds of ratings. These were collapsed into 12 statements for the final consensus reported here. The term 'Language Disorder' is recommended to refer to a profile of difficulties that causes functional impairment in everyday life and is associated with poor prognosis. The term, 'Developmental Language Disorder' (DLD) was endorsed for use when the language disorder was not associated with a known biomedical aetiology. It was also agreed that (a) presence of risk factors (neurobiological or environmental) does not preclude a diagnosis of DLD, (b) DLD can co-occur with other neurodevelopmental disorders (e.g. ADHD) and (c) DLD does not require a mismatch between verbal and nonverbal ability. CONCLUSIONS This Delphi exercise highlights reasons for disagreements about terminology for language disorders and proposes standard definitions and nomenclature.
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Affiliation(s)
| | | | - Paul A. Thompson
- Department of Experimental PsychologyUniversity of OxfordOxfordUK
| | - Trisha Greenhalgh
- Nuffield Department of Primary Care Health SciencesUniversity of OxfordOxfordUK
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Mascheretti S, Gori S, Trezzi V, Ruffino M, Facoetti A, Marino C. Visual motion and rapid auditory processing are solid endophenotypes of developmental dyslexia. GENES BRAIN AND BEHAVIOR 2017; 17:70-81. [PMID: 28834383 DOI: 10.1111/gbb.12409] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/19/2017] [Accepted: 08/14/2017] [Indexed: 12/18/2022]
Abstract
Although a genetic component is known to have an important role in the etiology of developmental dyslexia (DD), we are far from understanding the molecular etiopathogenetic pathways. Reduced measures of neurobiological functioning related to reading (dis)ability, i.e. endophenotypes (EPs), are promising targets for gene finding and the elucidation of the underlying mechanisms. In a sample of 100 nuclear families with DD (229 offspring) and 83 unrelated typical readers, we tested whether a set of well-established, cognitive phenotypes related to DD [i.e. rapid auditory processing (RAP), rapid automatized naming (RAN), multisensory nonspatial attention and visual motion processing] fulfilled the criteria of the EP construct. Visual motion and RAP satisfied all testable criteria (i.e. they are heritable, associate with the disorder, co-segregate with the disorder within a family and represent reproducible measures) and are therefore solid EPs of DD. Multisensory nonspatial attention satisfied three of four criteria (i.e. it associates with the disorder, co-segregates with the disorder within a family and represents a reproducible measure) and is therefore a potential EP for DD. Rapid automatized naming is heritable but does not meet other criteria of the EP construct. We provide the first evidence of a methodologically and statistically sound approach for identifying EPs for DD to be exploited as a solid alternative basis to clinical phenotypes in neuroscience.
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Affiliation(s)
- S. Mascheretti
- Child Psychopathology Unit; Scientific Institute, IRCCS Eugenio Medea; Bosisio Parini Italy
| | - S. Gori
- Child Psychopathology Unit; Scientific Institute, IRCCS Eugenio Medea; Bosisio Parini Italy
- Department of Human and Social Sciences; University of Bergamo; Bergamo Italy
| | - V. Trezzi
- Child Psychopathology Unit; Scientific Institute, IRCCS Eugenio Medea; Bosisio Parini Italy
| | - M. Ruffino
- Child Psychopathology Unit; Scientific Institute, IRCCS Eugenio Medea; Bosisio Parini Italy
| | - A. Facoetti
- Child Psychopathology Unit; Scientific Institute, IRCCS Eugenio Medea; Bosisio Parini Italy
- Developmental Cognitive Neuroscience Lab, Department of General Psychology; University of Padua; Padua Italy
| | - C. Marino
- Child Psychopathology Unit; Scientific Institute, IRCCS Eugenio Medea; Bosisio Parini Italy
- Centre for Addiction and Mental Health; University of Toronto; ON Canada
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33
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The role of READ1 and KIAA0319 genetic variations in developmental dyslexia: testing main and interactive effects. J Hum Genet 2017; 62:949-955. [DOI: 10.1038/jhg.2017.80] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/30/2017] [Accepted: 07/02/2017] [Indexed: 12/23/2022]
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34
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Parrila RK, Protopapas A. Dyslexia and word reading problems. STUDIES IN WRITTEN LANGUAGE AND LITERACY 2017. [DOI: 10.1075/swll.15.19par] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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35
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Selzam S, Dale PS, Wagner RK, DeFries JC, Cederlöf M, O’Reilly PF, Krapohl E, Plomin R. Genome-Wide Polygenic Scores Predict Reading Performance Throughout the School Years. SCIENTIFIC STUDIES OF READING : THE OFFICIAL JOURNAL OF THE SOCIETY FOR THE SCIENTIFIC STUDY OF READING 2017; 21:334-349. [PMID: 28706435 PMCID: PMC5490720 DOI: 10.1080/10888438.2017.1299152] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
It is now possible to create individual-specific genetic scores, called genome-wide polygenic scores (GPS). We used a GPS for years of education (EduYears) to predict reading performance assessed at UK National Curriculum Key Stages 1 (age 7), 2 (age 12) and 3 (age 14) and on reading tests administered at ages 7 and 12 in a UK sample of 5,825 unrelated individuals. EduYears GPS accounts for up to 5% of the variance in reading performance at age 14. GPS predictions remained significant after accounting for general cognitive ability and family socioeconomic status. Reading performance of children in the lowest and highest 12.5% of the EduYears GPS distribution differed by a mean growth in reading ability of approximately two school years. It seems certain that polygenic scores will be used to predict strengths and weaknesses in education.
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36
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Schaars MM, Segers E, Verhoeven L. Word Decoding Development during Phonics Instruction in Children at Risk for Dyslexia. DYSLEXIA (CHICHESTER, ENGLAND) 2017; 23:141-160. [PMID: 28470910 PMCID: PMC6084288 DOI: 10.1002/dys.1556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/20/2017] [Accepted: 03/20/2017] [Indexed: 06/07/2023]
Abstract
In the present study, we examined the early word decoding development of 73 children at genetic risk of dyslexia and 73 matched controls. We conducted monthly curriculum-embedded word decoding measures during the first 5 months of phonics-based reading instruction followed by standardized word decoding measures halfway and by the end of first grade. In kindergarten, vocabulary, phonological awareness, lexical retrieval, and verbal and visual short-term memory were assessed. The results showed that the children at risk were less skilled in phonemic awareness in kindergarten. During the first 5 months of reading instruction, children at risk were less efficient in word decoding and the discrepancy increased over the months. In subsequent months, the discrepancy prevailed for simple words but increased for more complex words. Phonemic awareness and lexical retrieval predicted the reading development in children at risk and controls to the same extent. It is concluded that children at risk are behind their typical peers in word decoding development starting from the very beginning. Furthermore, it is concluded that the disadvantage increased during phonics instruction and that the same predictors underlie the development of word decoding in the two groups of children. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Eliane Segers
- Behavioural Science InstituteRadboud UniversityNijmegenThe Netherlands
| | - Ludo Verhoeven
- Behavioural Science InstituteRadboud UniversityNijmegenThe Netherlands
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37
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Shriberg LD, Strand EA, Fourakis M, Jakielski KJ, Hall SD, Karlsson HB, Mabie HL, McSweeny JL, Tilkens CM, Wilson DL. A Diagnostic Marker to Discriminate Childhood Apraxia of Speech From Speech Delay: IV. The Pause Marker Index. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2017; 60:S1153-S1169. [PMID: 28384662 PMCID: PMC5548089 DOI: 10.1044/2016_jslhr-s-16-0149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 08/02/2016] [Accepted: 08/21/2016] [Indexed: 05/07/2023]
Abstract
Purpose Three previous articles provided rationale, methods, and several forms of validity support for a diagnostic marker of childhood apraxia of speech (CAS), termed the pause marker (PM). Goals of the present article were to assess the validity and stability of the PM Index (PMI) to scale CAS severity. Method PM scores and speech, prosody, and voice precision-stability data were obtained for participants with CAS in idiopathic, neurogenetic, and complex neurodevelopmental disorders; adult-onset apraxia of speech consequent to stroke and primary progressive apraxia; and idiopathic speech delay. Three studies were completed including criterion and concurrent validity studies of the PMI and a temporal stability study of the PMI using retrospective case studies. Results PM scores were significantly correlated with other signs of CAS precision and stability. The best fit of the distribution of PM scores to index CAS severity was obtained by dividing scores into 4 ordinal severity classifications: mild, mild-moderate, moderate-severe, and severe. Severity findings for the 4 classifications and retrospective longitudinal findings from 8 participants with CAS supported the validity and stability of the PMI. Conclusion Findings support research and clinical use of the PMI to scale the severity of CAS.
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Affiliation(s)
| | | | | | - Kathy J. Jakielski
- Department of Communication Sciences and Disorders, Augustana College, Rock Island, IL
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38
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Ulfarsson MO, Walters GB, Gustafsson O, Steinberg S, Silva A, Doyle OM, Brammer M, Gudbjartsson DF, Arnarsdottir S, Jonsdottir GA, Gisladottir RS, Bjornsdottir G, Helgason H, Ellingsen LM, Halldorsson JG, Saemundsen E, Stefansdottir B, Jonsson L, Eiriksdottir VK, Eiriksdottir GR, Johannesdottir GH, Unnsteinsdottir U, Jonsdottir B, Magnusdottir BB, Sulem P, Thorsteinsdottir U, Sigurdsson E, Brandeis D, Meyer-Lindenberg A, Stefansson H, Stefansson K. 15q11.2 CNV affects cognitive, structural and functional correlates of dyslexia and dyscalculia. Transl Psychiatry 2017; 7:e1109. [PMID: 28440815 PMCID: PMC5416713 DOI: 10.1038/tp.2017.77] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 02/07/2023] Open
Abstract
Several copy number variants have been associated with neuropsychiatric disorders and these variants have been shown to also influence cognitive abilities in carriers unaffected by psychiatric disorders. Previously, we associated the 15q11.2(BP1-BP2) deletion with specific learning disabilities and a larger corpus callosum. Here we investigate, in a much larger sample, the effect of the 15q11.2(BP1-BP2) deletion on cognitive, structural and functional correlates of dyslexia and dyscalculia. We report that the deletion confers greatest risk of the combined phenotype of dyslexia and dyscalculia. We also show that the deletion associates with a smaller left fusiform gyrus. Moreover, tailored functional magnetic resonance imaging experiments using phonological lexical decision and multiplication verification tasks demonstrate altered activation in the left fusiform and the left angular gyri in carriers. Thus, by using convergent evidence from neuropsychological testing, and structural and functional neuroimaging, we show that the 15q11.2(BP1-BP2) deletion affects cognitive, structural and functional correlates of both dyslexia and dyscalculia.
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Affiliation(s)
- M O Ulfarsson
- deCODE Genetics/Amgen, Reykjavik, Iceland,Faculty of Electrical and Computer Engineering, University of Iceland, Reykjavik, Iceland,deCODE Genetics/Amgen, Sturlugata 8, 101 Reykjavik, Iceland. E-mail: or
| | | | | | | | - A Silva
- Cardiff University Brain Imaging Research Center, Cardiff University, Cardiff, UK
| | - O M Doyle
- Institute of Psychiatry, King's College, London, UK
| | - M Brammer
- Institute of Psychiatry, King's College, London, UK
| | - D F Gudbjartsson
- deCODE Genetics/Amgen, Reykjavik, Iceland,Faculty of Physical Sciences, University of Iceland, Reykjavik, Iceland
| | - S Arnarsdottir
- deCODE Genetics/Amgen, Reykjavik, Iceland,Department of Psychiatry, Landspitali National University Hospital, Reykjavik, Iceland
| | | | | | | | - H Helgason
- deCODE Genetics/Amgen, Reykjavik, Iceland,Faculty of Electrical and Computer Engineering, University of Iceland, Reykjavik, Iceland
| | - L M Ellingsen
- Faculty of Electrical and Computer Engineering, University of Iceland, Reykjavik, Iceland
| | - J G Halldorsson
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - E Saemundsen
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland,The State Diagnosis and Counselling Center, Kopavogur, Iceland
| | | | - L Jonsson
- deCODE Genetics/Amgen, Reykjavik, Iceland
| | | | | | | | | | | | - B B Magnusdottir
- Department of Psychiatry, Landspitali National University Hospital, Reykjavik, Iceland,School of Business, University of Reykjavik, Reykavik, Iceland
| | - P Sulem
- deCODE Genetics/Amgen, Reykjavik, Iceland
| | - U Thorsteinsdottir
- deCODE Genetics/Amgen, Reykjavik, Iceland,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - E Sigurdsson
- Department of Psychiatry, Landspitali National University Hospital, Reykjavik, Iceland,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - D Brandeis
- Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric Hospital, University of Zurich, Zurich, Switzerland,Central Institute of Mental Health, University of Heidelberg Medical Faculty Mannheim, Mannheim, Germany
| | - A Meyer-Lindenberg
- Central Institute of Mental Health, University of Heidelberg Medical Faculty Mannheim, Mannheim, Germany
| | | | - K Stefansson
- deCODE Genetics/Amgen, Reykjavik, Iceland,Faculty of Medicine, University of Iceland, Reykjavik, Iceland,deCODE Genetics/Amgen, Sturlugata 8, 101 Reykjavik, Iceland. E-mail: or
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39
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A Psychometric Tool for a Virtual Reality Rehabilitation Approach for Dyslexia. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2017; 2017:7048676. [PMID: 28286543 PMCID: PMC5327757 DOI: 10.1155/2017/7048676] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 01/19/2017] [Indexed: 11/18/2022]
Abstract
Dyslexia is a chronic problem that affects the life of subjects and often influences their life choices. The standard rehabilitation methods all use a classic paper and pencil training format but these exercises are boring and demanding for children who may have difficulty in completing the treatments. It is important to develop a new rehabilitation program that would help children in a funny and engaging way. A Wii-based game was developed to demonstrate that a short treatment with an action video game, rather than phonological or orthographic training, may improve the reading abilities in dyslexic children. According to the results, an approach using cues in the context of a virtual environment may represent a promising tool to improve attentional skills. On the other hand, our results do not demonstrate an immediate effect on reading performance, suggesting that a more prolonged protocol may be a future direction.
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40
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Neurogenetics of developmental dyslexia: from genes to behavior through brain neuroimaging and cognitive and sensorial mechanisms. Transl Psychiatry 2017; 7:e987. [PMID: 28045463 PMCID: PMC5545717 DOI: 10.1038/tp.2016.240] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/15/2016] [Indexed: 01/18/2023] Open
Abstract
Developmental dyslexia (DD) is a complex neurodevelopmental deficit characterized by impaired reading acquisition, in spite of adequate neurological and sensorial conditions, educational opportunities and normal intelligence. Despite the successful characterization of DD-susceptibility genes, we are far from understanding the molecular etiological pathways underlying the development of reading (dis)ability. By focusing mainly on clinical phenotypes, the molecular genetics approach has yielded mixed results. More optimally reduced measures of functioning, that is, intermediate phenotypes (IPs), represent a target for researching disease-associated genetic variants and for elucidating the underlying mechanisms. Imaging data provide a viable IP for complex neurobehavioral disorders and have been extensively used to investigate both morphological, structural and functional brain abnormalities in DD. Performing joint genetic and neuroimaging studies in humans is an emerging strategy to link DD-candidate genes to the brain structure and function. A limited number of studies has already pursued the imaging-genetics integration in DD. However, the results are still not sufficient to unravel the complexity of the reading circuit due to heterogeneous study design and data processing. Here, we propose an interdisciplinary, multilevel, imaging-genetic approach to disentangle the pathways from genes to behavior. As the presence of putative functional genetic variants has been provided and as genetic associations with specific cognitive/sensorial mechanisms have been reported, new hypothesis-driven imaging-genetic studies must gain momentum. This approach would lead to the optimization of diagnostic criteria and to the early identification of 'biologically at-risk' children, supporting the definition of adequate and well-timed prevention strategies and the implementation of novel, specific remediation approach.
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41
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Hart S. Precision Education Initiative: Moving Towards Personalized Education. MIND, BRAIN AND EDUCATION : THE OFFICIAL JOURNAL OF THE INTERNATIONAL MIND, BRAIN, AND EDUCATION SOCIETY 2016; 10:209-211. [PMID: 28642807 PMCID: PMC5476312 DOI: 10.1111/mbe.12109] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
ABSTRACTThis article propose the Precision Education Initiative, which is the tailoring of education to the specific characteristics of the individual student. Mirroring precision medicine, the author lays out both near‐term and longer term goals that educational research, and importantly educational practice, should follow.
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Affiliation(s)
- S.A. Hart
- Department of Psychology, Florida Center for Reading Research, Florida State University
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42
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Powers SJ, Wang Y, Beach SD, Sideridis GD, Gaab N. Examining the relationship between home literacy environment and neural correlates of phonological processing in beginning readers with and without a familial risk for dyslexia: an fMRI study. ANNALS OF DYSLEXIA 2016; 66:337-360. [PMID: 27550556 PMCID: PMC5061614 DOI: 10.1007/s11881-016-0134-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/03/2016] [Indexed: 05/13/2023]
Abstract
Developmental dyslexia is a language-based learning disability characterized by persistent difficulty in learning to read. While an understanding of genetic contributions is emerging, the ways the environment affects brain functioning in children with developmental dyslexia are poorly understood. A relationship between the home literacy environment (HLE) and neural correlates of reading has been identified in typically developing children, yet it remains unclear whether similar effects are observable in children with a genetic predisposition for dyslexia. Understanding environmental contributions is important given that we do not understand why some genetically at-risk children do not develop dyslexia. Here, we investigate for the first time the relationship between HLE and the neural correlates of phonological processing in beginning readers with (FHD+, n = 29) and without (FHD-, n = 21) a family history of developmental dyslexia. We further controlled for socioeconomic status to isolate the neurobiological mechanism by which HLE affects reading development. Group differences revealed stronger correlation of HLE with brain activation in the left inferior/middle frontal and right fusiform gyri in FHD- compared to FHD+ children, suggesting greater impact of HLE on manipulation of phonological codes and recruitment of orthographic representations in typically developing children. In contrast, activation in the right precentral gyrus showed a significantly stronger correlation with HLE in FHD+ compared to FHD- children, suggesting emerging compensatory networks in genetically at-risk children. Overall, our results suggest that genetic predisposition for dyslexia alters contributions of HLE to early reading skills before formal reading instruction, which has important implications for educational practice and intervention models.
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Affiliation(s)
- Sara J Powers
- Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Yingying Wang
- Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Sara D Beach
- Speech and Hearing Bioscience and Technology Program, Division of Medical Sciences, Harvard University, Boston, MA, USA
| | - Georgios D Sideridis
- Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Nadine Gaab
- Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
- Harvard Graduate School of Education, Cambridge, MA, USA.
- Department of Medicine, Division of Developmental Medicine, Laboratories of Cognitive Neuroscience, Children's Hospital, Boston, 1 Autumn Street, Mailbox # 713, Boston, MA, 02115, USA.
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Gabel LA, Manglani M, Escalona N, Cysner J, Hamilton R, Pfaffmann J, Johnson E. Translating dyslexia across species. ANNALS OF DYSLEXIA 2016; 66:319-336. [PMID: 27013331 DOI: 10.1007/s11881-016-0125-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 02/01/2016] [Indexed: 06/05/2023]
Abstract
Direct relationships between induced mutation in the DCDC2 candidate dyslexia susceptibility gene in mice and changes in behavioral measures of visual spatial learning have been reported. We were interested in determining whether performance on a visual-spatial learning and memory task could be translated across species (study 1) and whether children with reading impairment showed a similar impairment to animal models of the disorder (study 2). Study 1 included 37 participants who completed six trials of four different virtual Hebb-Williams maze configurations. A 2 × 4 × 6 mixed factorial repeated measures ANOVA indicated consistency in performance between humans and mice on these tasks, enabling us to translate across species. Study 2 included a total of 91 participants (age range = 8-13 years). Eighteen participants were identified with reading disorder by performance on the Woodcock-Johnson III Tests of Achievement. Participants completed six trials of five separate virtual Hebb-Williams maze configurations. A 2 × 5 × 6 mixed factorial ANCOVA (gender as covariate) indicated that individuals with reading impairment demonstrated impaired visuo-spatial performance on this task. Overall, results from this study suggest that we are able to translate behavioral deficits observed in genetic animal models of dyslexia to humans with reading impairment. Future studies will utilize the virtual environment to further explore the underlying basis for this impairment.
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Affiliation(s)
- Lisa A Gabel
- Department of Psychology, Lafayette College, Easton, PA, USA.
- Program in Neuroscience, Lafayette College, Easton, PA, USA.
| | | | | | - Jessica Cysner
- Program in Neuroscience, Lafayette College, Easton, PA, USA
| | | | | | - Evelyn Johnson
- Department of Special Education, Boise State University, Boise, ID, USA
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Konrad K, Schulte-Körne G. [Specific Learning Disabilities: Current challenges and opportunities]. ZEITSCHRIFT FUR KINDER-UND JUGENDPSYCHIATRIE UND PSYCHOTHERAPIE 2016; 44:329-332. [PMID: 27658625 DOI: 10.1024/1422-4917/a000470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Kerstin Konrad
- 1 Lehr- und Forschungsgebiet Klinische Neuropsychologie des Kindes- und Jugendalters, Klinik für Kinder- und Jugendpsychiatrie, -psychosomatik und -psychotherapie, Universitätsklinikum der RWTH Aachen, Deutschland.,2 JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH und RWTH Aachen University, Deutschland
| | - Gerd Schulte-Körne
- 3 Klinik und Poliklinik für Kinder- und Jugendpsychiatrie, Psychosomatik und Psychotherapie, Klinikum der Universität München, Deutschland
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45
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Little CW, Haughbrook R, Hart SA. Cross-Study Differences in the Etiology of Reading Comprehension: a Meta-Analytical Review of Twin Studies. Behav Genet 2016; 47:52-76. [PMID: 27630039 DOI: 10.1007/s10519-016-9810-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 08/24/2016] [Indexed: 11/28/2022]
Abstract
Numerous twin studies have examined the genetic and environmental etiology of reading comprehension, though it is likely that etiological estimates are influenced by unidentified sample conditions (e.g. Tucker-Drob and Bates, Psychol Sci:0956797615612727, 2015). The purpose of this meta-analysis was to average the etiological influences of reading comprehension and to explore the potential moderators influencing these estimates. Results revealed an average heritability estimate of h2 = 0.59, with significant variation in estimates across studies, suggesting potential moderation. Moderation results indicated publication year, grade level, project, zygosity methods, and response type moderated heritability estimates. The average shared environmental estimate was c2 = 0.16, with publication year, grade and zygosity methods acting as significant moderators. These findings support the role of genetics on reading comprehension, and a small significant role of shared environmental influences. The results suggest that our interpretation of how genes and environments influence reading comprehension should reflect aspects of study and sample.
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Affiliation(s)
- Callie W Little
- Department of Psychology, Florida State University, 1107 W. Call Street, Tallahassee, FL, 32306, USA.
| | - Rasheda Haughbrook
- Department of Psychology, Florida State University, 1107 W. Call Street, Tallahassee, FL, 32306, USA
| | - Sara A Hart
- Department of Psychology, Florida State University, 1107 W. Call Street, Tallahassee, FL, 32306, USA.,Florida Center for Reading Research, Florida State University, 2010 Levy Avenue, Tallahassee, FL, 32310, USA
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46
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Paracchini S, Diaz R, Stein J. Advances in Dyslexia Genetics—New Insights Into the Role of Brain Asymmetries. ADVANCES IN GENETICS 2016; 96:53-97. [DOI: 10.1016/bs.adgen.2016.08.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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47
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Cappa C, Giulivi S, Schilirò A, Bastiani L, Muzio C, Meloni F. A screening on Specific Learning Disorders in an Italian speaking high genetic homogeneity area. RESEARCH IN DEVELOPMENTAL DISABILITIES 2015; 45-46:329-342. [PMID: 26296080 DOI: 10.1016/j.ridd.2015.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 07/09/2015] [Accepted: 07/13/2015] [Indexed: 06/04/2023]
Abstract
The aim of the present research is to investigate the prevalence of Specific Learning Disorders (SLD) in Ogliastra, an area of the island of Sardinia, Italy. Having experienced centuries of isolation, Ogliastra has become a high genetic homogeneity area, and is considered particularly interesting for studies on different kinds of pathologies. Here we are going to describe the results of a screening carried out throughout 2 consecutive years in 49 second grade classes (24 considered in the first year and 25 in the second year of the study) of the Ogliastra region. A total of 610 pupils (average age 7.54 years; 293 female, 317 male) corresponding to 68.69% of all pupils who were attending second grade in the area, took part in the study. The tool used for the screening was "RSR-DSA. Questionnaire for the detection of learning difficulties and disorders", which allowed the identification of 83 subjects at risk (13.61% of the whole sample involved in the study). These subjects took part in an enhancement training program of about 6 months. After the program, pupils underwent assessment for reading, writing and calculation abilities, as well as cognitive assessment. According to the results of the assessment, the prevalence of SLDs is 6.06%. For what concerns dyslexia, 4.75% of the total sample manifested this disorder either in isolation or in comorbidity with other disorders. According to the first national epidemiological investigation carried out in Italy, the prevalence of dyslexia is 3.1-3.2%, which is lower than the prevalence obtained in the present study. Given the genetic basis of SLDs, this result, together with the presence of several cases of SLD in isolation (17.14%) and with a 3:1 ratio of males to females diagnosed with a SLD, was to be expected in a sample coming from a high genetic homogeneity area.
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Affiliation(s)
- Claudia Cappa
- Institute of Clinical Physiology (IFC), CNR, Pisa, Italy.
| | - Sara Giulivi
- Department of Teaching and Learning (DFA) - University School of Applied Sciences and Arts of Southern Switzerland (SUPSI), Locarno, Switzerland.
| | - Antonino Schilirò
- Service of Child Neuropsychiatry, Azienda Sanitaria Locale 4, Lanusei, Italy.
| | - Luca Bastiani
- Institute of Clinical Physiology (IFC), CNR, Pisa, Italy.
| | - Carlo Muzio
- Istituto Santo Stefano, Porto Potenza Picena (MC), Italy.
| | - Fabrizio Meloni
- Service of Child Neuropsychiatry, Azienda Sanitaria Locale 4, Lanusei, Italy.
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