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Lasnick OHM, Hoeft F. Sensory temporal sampling in time: an integrated model of the TSF and neural noise hypothesis as an etiological pathway for dyslexia. Front Hum Neurosci 2024; 17:1294941. [PMID: 38234592 PMCID: PMC10792016 DOI: 10.3389/fnhum.2023.1294941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/04/2023] [Indexed: 01/19/2024] Open
Abstract
Much progress has been made in research on the causal mechanisms of developmental dyslexia. In recent years, the "temporal sampling" account of dyslexia has evolved considerably, with contributions from neurogenetics and novel imaging methods resulting in a much more complex etiological view of the disorder. The original temporal sampling framework implicates disrupted neural entrainment to speech as a causal factor for atypical phonological representations. Yet, empirical findings have not provided clear evidence of a low-level etiology for this endophenotype. In contrast, the neural noise hypothesis presents a theoretical view of the manifestation of dyslexia from the level of genes to behavior. However, its relative novelty (published in 2017) means that empirical research focused on specific predictions is sparse. The current paper reviews dyslexia research using a dual framework from the temporal sampling and neural noise hypotheses and discusses the complementary nature of these two views of dyslexia. We present an argument for an integrated model of sensory temporal sampling as an etiological pathway for dyslexia. Finally, we conclude with a brief discussion of outstanding questions.
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Affiliation(s)
- Oliver H. M. Lasnick
- brainLENS Laboratory, Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
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2
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Zaki ZMM, Ali SA, Ghazali MM, Jam FA. Genetic Modifications of Developmental Dyslexia and Its Representation Using In Vivo, In Vitro Model. Glob Med Genet 2024; 11:76-85. [PMID: 38414980 PMCID: PMC10898997 DOI: 10.1055/s-0044-1781456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024] Open
Abstract
Dyslexia is a genetic and heritable disorder that has yet to discover the treatment of it, especially at the molecular and drug intervention levels. This review provides an overview of the current findings on the environmental and genetic factors involved in developmental dyslexia. The latest techniques used in diagnosing the disease and macromolecular factors findings may contribute to a higher degree of development in detangling the proper management and treatment for dyslexic individuals. Furthermore, this review tried to put together all the models used in the current dyslexia research for references in future studies that include animal models as well as in vitro models and how the previous research has provided consistent data across many years and regions. Thus, we suggest furthering the studies using an organoid model based on the existing gene polymorphism, pathways, and neuronal function input.
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Affiliation(s)
- Zakiyyah M M Zaki
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Siti A Ali
- Department of Electronic Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
- Centre for Healthcare Science and Technology, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
| | - Mazira M Ghazali
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
- Faculty of Medicine, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Faidruz A Jam
- Department of Biochemistry, Faculty of Medicine, Manipal University College Malaysia, Melaka, Malaysia
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3
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Barrington E, Sarkisian SM, Feldman HM, Yeatman JD. Rapid Online Assessment of Reading (ROAR): Evaluation of an Online Tool for Screening Reading Skills in a Developmental-Behavioral Pediatrics Clinic. J Dev Behav Pediatr 2023; 44:e604-e610. [PMID: 38016008 PMCID: PMC10686102 DOI: 10.1097/dbp.0000000000001226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/18/2023] [Indexed: 11/30/2023]
Abstract
OBJECTIVE Reading difficulties are highly prevalent and frequently co-occur with other neurodevelopmental/behavioral conditions. It is difficult to assess reading routinely in pediatric clinical practice because of time and resource constraints. Rapid Online Assessment of Reading (ROAR) is an objective, gamified assessment that children take in a web browser without adult supervision. This study's purpose was to evaluate ROAR as a screening tool for reading difficulties in a clinical setting. METHOD A convenience sample of 6- to 14-year-old children, attending an in-person or telehealth visit in a developmental-behavioral pediatrics (DBP) clinic participated. Children took ROAR and completed the Woodcock-Johnson IV Letter-Word Identification (LWID) and Word Attack (WA). Basic Reading Skills (BRS), a standardized aggregate score of LWID and WA, was used as the gold-standard assessment. The strength of association between standard scores on ROAR and BRS was calculated. BRS scores < 90 (bottom quartile) were classified as poor readers. Receiver operating characteristic (ROC) curve analysis was used to assess the quality of ROAR as a screening test. RESULTS A sample of 41 children, 78% boys, mean age 9.5 years (SD 2.0 years), completed the study. The correlation of ROAR standard score with BRS was r = 0.66, p < 0.001. ROC curve analysis with ROAR scores accurately classified poor readers with an area under the curve (AUC) of 0.90. CONCLUSION ROAR is a useful objective screening tool to identify children at high risk for reading difficulties. Assessment of the tool during a busy clinic was challenging, and a larger replication is warranted.
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Affiliation(s)
- Elizabeth Barrington
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, School of Medicine, Stanford University, Stanford CA
| | | | - Heidi M. Feldman
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, School of Medicine, Stanford University, Stanford CA
| | - Jason D. Yeatman
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, School of Medicine, Stanford University, Stanford CA
- Graduate School of Education, Stanford University
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Glatz T, Tops W, Borleffs E, Richardson U, Maurits N, Desoete A, Maassen B. Dynamic assessment of the effectiveness of digital game-based literacy training in beginning readers: a cluster randomised controlled trial. PeerJ 2023; 11:e15499. [PMID: 37547712 PMCID: PMC10399564 DOI: 10.7717/peerj.15499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 05/12/2023] [Indexed: 08/08/2023] Open
Abstract
In this article, we report on a study evaluating the effectiveness of a digital game-based learning (DGBL) tool for beginning readers of Dutch, employing active (math game) and passive (no game) control conditions. This classroom-level randomized controlled trial included 247 first graders from 16 classrooms in the Netherlands and the Dutch-speaking part of Belgium. The intervention consisted of 10 to 15 min of daily playing during school time for a period of up to 7 weeks. Our outcome measures included reading fluency, phonological skills, as well as purpose built in-game proficiency levels to measure written lexical decision and letter speech sound association. After an average of 28 playing sessions, the literacy game improved letter knowledge at a scale generalizable for all children in the classroom compared to the two control conditions. In addition to a small classroom wide benefit in terms of reading fluency, we furthermore discovered that children who scored high on phonological awareness prior to training were more fluent readers after extensive exposure to the reading game. This study is among the first to exploit game generated data for the evaluation of DGBL for literacy interventions.
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Affiliation(s)
- Toivo Glatz
- Center for Language and Cognition (CLCG), Faculty of Arts, University of Groningen, Groningen, Netherlands
- Institute of Public Health, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Behaviour and Cognitive Neuroscience (BCN), University Medical Center Groningen (UMCG), University of Groningen, Groningen, Netherlands
| | - Wim Tops
- School of Educational Studies, Universiteit Hasselt, Hasselt, Belgium
| | - Elisabeth Borleffs
- Center for Language and Cognition (CLCG), Faculty of Arts, University of Groningen, Groningen, Netherlands
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry, University of Zurich, Zurich, Switzerland
| | - Ulla Richardson
- Centre for Applied Language Studies, University of Jyväskylä, Jyväskylä, Finland
| | - Natasha Maurits
- Behaviour and Cognitive Neuroscience (BCN), University Medical Center Groningen (UMCG), University of Groningen, Groningen, Netherlands
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Annemie Desoete
- Department of Experimental Clinical and Health Psychology Ghent University, Gent, Belgium
- Artevelde University College of Applied Sciences, Gent, Belgium
| | - Ben Maassen
- Center for Language and Cognition (CLCG), Faculty of Arts, University of Groningen, Groningen, Netherlands
- Behaviour and Cognitive Neuroscience (BCN), University Medical Center Groningen (UMCG), University of Groningen, Groningen, Netherlands
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5
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Kristjánsson Á, Sigurdardottir HM. The Role of Visual Factors in Dyslexia. J Cogn 2023; 6:31. [PMID: 37397349 PMCID: PMC10312247 DOI: 10.5334/joc.287] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 06/13/2023] [Indexed: 07/04/2023] Open
Abstract
What are the causes of dyslexia? Decades of research reflect a determined search for a single cause where a common assumption is that dyslexia is a consequence of problems with converting phonological information into lexical codes. But reading is a highly complex activity requiring many well-functioning mechanisms, and several different visual problems have been documented in dyslexic readers. We critically review evidence from various sources for the role of visual factors in dyslexia, from magnocellular dysfunction through accounts based on abnormal eye movements and attentional processing, to recent proposals that problems with high-level vision contribute to dyslexia. We believe that the role of visual problems in dyslexia has been underestimated in the literature, to the detriment of the understanding and treatment of the disorder. We propose that rather than focusing on a single core cause, the role of visual factors in dyslexia fits well with risk and resilience models that assume that several variables interact throughout prenatal and postnatal development to either promote or hinder efficient reading.
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Affiliation(s)
- Árni Kristjánsson
- Icelandic Vision Lab, Department of Psychology, University of Iceland, IS
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Rinaldi P, Bello A, Simonelli I, Caselli MC. Is Specific Learning Disorder Predicted by Developmental Language Disorder? Evidence from a Follow-Up Study on Italian Children. Brain Sci 2023; 13:brainsci13040701. [PMID: 37190666 DOI: 10.3390/brainsci13040701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 05/17/2023] Open
Abstract
Specific Learning Disorder (SLD) is a complex disorder with a strong genetic component, characterized by varying manifestations and considerable differences among children. Several studies have highlighted that difficulties in language acquisition and the presence of Developmental Language Disorders (DLDs) are frequently associated with SLD, suggesting a continuity between the two disorders. This study aimed to add evidence on the proximal and distal predictors of SLD, focusing on the eventual continuity for the presence of DLD at 4-5 years, on some linguistic and communicative abilities at 27-30 months, and on biological and environmental factors. Our sample consisted of 528 families, whose children (Italian monolingual) participated in a screening program at the age of 27-30 months. When children were on average 8.05 years old, parents were asked to answer an interview aimed at collecting information about the children's language and learning development. Results showed that the prevalence of children with an SLD (7.01%) was in line with those reported in other similar studies. The diagnosis of SLD was significantly predicted by the previous diagnosis of DLD, by male sex/gender, and by the familial risk of SLD. Children with these characteristics had a 54% probability of presenting an SLD.
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Affiliation(s)
- Pasquale Rinaldi
- Institute of Cognitive Sciences and Technologies, National Research Council, Via Nomentana 56, 00161 Rome, Italy
| | - Arianna Bello
- Department of Education, Roma Tre University, Via Castro Pretorio 20, 00185 Rome, Italy
| | - Ilaria Simonelli
- Clinical Trial Center Fatebenefratelli Tiberina Island-Gemelli Island, Via di Ponte Quattro Capi 39, 00186 Rome, Italy
| | - Maria Cristina Caselli
- Institute of Cognitive Sciences and Technologies, National Research Council, Via Nomentana 56, 00161 Rome, Italy
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Church JA, Grigorenko EL, Fletcher JM. The Role of Neural and Genetic Processes in Learning to Read and Specific Reading Disabilities: Implications for Instruction. READING RESEARCH QUARTERLY 2023; 58:203-219. [PMID: 37456924 PMCID: PMC10348696 DOI: 10.1002/rrq.439] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 06/29/2021] [Indexed: 07/18/2023]
Abstract
To learn to read, the brain must repurpose neural systems for oral language and visual processing to mediate written language. We begin with a description of computational models for how alphabetic written language is processed. Next, we explain the roles of a dorsal sublexical system in the brain that relates print and speech, a ventral lexical system that develops the visual expertise for rapid orthographic processing at the word level, and the role of cognitive control networks that regulate attentional processes as children read. We then use studies of children, adult illiterates learning to read, and studies of poor readers involved in intervention, to demonstrate the plasticity of these neural networks in development and in relation to instruction. We provide a brief overview of the rapid increase in the field's understanding and technology for assessing genetic influence on reading. Family studies of twins have shown that reading skills are heritable, and molecular genetic studies have identified numerous regions of the genome that may harbor candidate genes for the heritability of reading. In selected families, reading impairment has been associated with major genetic effects, despite individual gene contributions across the broader population that appear to be small. Neural and genetic studies do not prescribe how children should be taught to read, but these studies have underscored the critical role of early intervention and ongoing support. These studies also have highlighted how structured instruction that facilitates access to the sublexical components of words is a critical part of training the brain to read.
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Affiliation(s)
| | - Elena L Grigorenko
- University of Houston, Texas, USA; Baylor College of Medicine, Houston, Texas, USA; and St. Petersburg State University, Russia
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8
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Price KM, Wigg KG, Nigam A, Feng Y, Blokland K, Wilkinson M, Kerr EN, Guger SL, Lovett MW, Strug LJ, Tripathy SJ, Barr CL. Identification of brain cell types underlying genetic association with word reading and correlated traits. Mol Psychiatry 2023; 28:1719-1730. [PMID: 36750735 DOI: 10.1038/s41380-023-01970-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 01/10/2023] [Accepted: 01/17/2023] [Indexed: 02/09/2023]
Abstract
Neuroimaging studies implicate multiple cortical regions in reading ability/disability. However, the neural cell types integral to the reading process are unknown. To contribute to this gap in knowledge, we integrated genetic results from genome-wide association studies for word reading (n = 5054) with gene expression datasets from adult/fetal human brain. Linkage disequilibrium score regression (LDSC) suggested that variants associated with word reading were enriched in genes expressed in adult excitatory neurons, specifically layer 5 and 6 FEZF2 expressing neurons and intratelencephalic (IT) neurons, which express the marker genes LINC00507, THEMIS, or RORB. Inhibitory neurons (VIP, SST, and PVALB) were also found. This finding was interesting as neurometabolite studies previously implicated excitatory-inhibitory imbalances in the etiology of reading disabilities (RD). We also tested traits that shared genetic etiology with word reading (previously determined by polygenic risk scores): attention-deficit/hyperactivity disorder (ADHD), educational attainment, and cognitive ability. For ADHD, we identified enrichment in L4 IT adult excitatory neurons. For educational attainment and cognitive ability, we confirmed previous studies identifying multiple subclasses of adult cortical excitatory and inhibitory neurons, as well as astrocytes and oligodendrocytes. For educational attainment and cognitive ability, we also identified enrichment in multiple fetal cortical excitatory and inhibitory neurons, intermediate progenitor cells, and radial glial cells. In summary, this study supports a role of excitatory and inhibitory neurons in reading and excitatory neurons in ADHD and contributes new information on fetal cell types enriched in educational attainment and cognitive ability, thereby improving our understanding of the neurobiological basis of reading/correlated traits.
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Affiliation(s)
- Kaitlyn M Price
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Karen G Wigg
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Anukrati Nigam
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Yu Feng
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Kirsten Blokland
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
| | - Margaret Wilkinson
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
| | - Elizabeth N Kerr
- Department of Psychology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics, University of Toronto, Toronto, ON, Canada
| | - Sharon L Guger
- Department of Psychology, Hospital for Sick Children, Toronto, ON, Canada
| | - Maureen W Lovett
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, ON, Canada.,Department of Pediatrics, University of Toronto, Toronto, ON, Canada
| | - Lisa J Strug
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON, Canada.,Departments of Statistical Sciences and Computer Science, Faculty of Arts and Science and Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Shreejoy J Tripathy
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Cathy L Barr
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada. .,Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, ON, Canada. .,Department of Physiology, University of Toronto, Toronto, ON, Canada. .,Institute of Medical Science, University of Toronto, Toronto, ON, Canada. .,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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9
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Price KM, Wigg KG, Eising E, Feng Y, Blokland K, Wilkinson M, Kerr EN, Guger SL, Fisher SE, Lovett MW, Strug LJ, Barr CL. Hypothesis-driven genome-wide association studies provide novel insights into genetics of reading disabilities. Transl Psychiatry 2022; 12:495. [PMID: 36446759 PMCID: PMC9709072 DOI: 10.1038/s41398-022-02250-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 11/30/2022] Open
Abstract
Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were located near to or in genes involved in neuronal migration/axon guidance (NM/AG) or loci implicated in autism spectrum disorder (ASD). A prominent theory of RD etiology posits that it involves disturbed neuronal migration, while potential links between RD-ASD have not been extensively investigated. To improve power to identify associated loci, we up-weighted variants involved in NM/AG or ASD, separately, and performed a new Hypothesis-Driven (HD)-GWAS. The approach was applied to a Toronto RD sample and a meta-analysis of the GenLang Consortium. For the Toronto sample (n = 624), no SNPs reached significance; however, by gene-set analysis, the joint contribution of ASD-related genes passed the threshold (p~1.45 × 10-2, threshold = 2.5 × 10-2). For the GenLang Cohort (n = 26,558), SNPs in DOCK7 and CDH4 showed significant association for the NM/AG hypothesis (sFDR q = 1.02 × 10-2). To make the GenLang dataset more similar to Toronto, we repeated the analysis restricting to samples selected for reading/language deficits (n = 4152). In this GenLang selected subset, we found significant association for a locus intergenic between BTG3-C21orf91 for both hypotheses (sFDR q < 9.00 × 10-4). This study contributes candidate loci to the genetics of word reading. Data also suggest that, although different variants may be involved, alleles implicated in ASD risk may be found in the same genes as those implicated in word reading. This finding is limited to the Toronto sample suggesting that ascertainment influences genetic associations.
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Affiliation(s)
- Kaitlyn M Price
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen G Wigg
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Else Eising
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Yu Feng
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kirsten Blokland
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Margaret Wilkinson
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth N Kerr
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Sharon L Guger
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Simon E Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Maureen W Lovett
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Lisa J Strug
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Departments of Statistical Sciences and Computer Science, Faculty of Arts and Science and Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Cathy L Barr
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
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10
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Silva PB, Oliveira DG, Cardoso AD, Laurence PG, Boggio PS, Macedo EC. Event-related potential and lexical decision task in dyslexic adults: Lexical and lateralization effects. Front Psychol 2022; 13:852219. [PMID: 36438365 PMCID: PMC9682126 DOI: 10.3389/fpsyg.2022.852219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 09/20/2022] [Indexed: 11/11/2022] Open
Abstract
Developmental dyslexia is a specific learning disorder that presents cognitive and neurobiological impairments related to different patterns of brain activation throughout development, continuing in adulthood. Lexical decision tasks, together with electroencephalography (EEG) measures that have great temporal precision, allow the capture of cognitive processes during the task, and can assist in the understanding of altered brain activation processes in adult dyslexics. High-density EEG allows the use of temporal analyses through event-related potentials (ERPs). The aim of this study was to compare and measure the pattern of ERPs in adults with developmental dyslexia and good readers, and to characterize and compare reading patterns between groups. Twenty university adults diagnosed with developmental dyslexia and 23 healthy adult readers paired with dyslexics participated in the study. The groups were assessed in tests of intelligence, phonological awareness, reading, and writing, as well as through the lexical decision test (LDT). During LDT, ERPs were recorded using a 128-channel EEG device. The ERPs P100 occipital, N170 occipito-temporal, N400 centro-parietal, and LPC centro-parietal were analyzed. The results showed a different cognitive profile between the groups in the reading, phonological awareness, and writing tests but not in the intelligence test. In addition, the brain activation pattern of the ERPs was different between the groups in terms of hemispheric lateralization, with higher amplitude of N170 in the dyslexia group in the right hemisphere and opposite pattern in the control group and specificities in relation to the items of the LDT, as the N400 were more negative in the Dyslexia group for words, while in the control group, this ERP was more pronounced in the pseudowords. These results are important for understanding different brain patterns in developmental dyslexia and can better guide future interventions according to the changes found in the profile.
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Affiliation(s)
| | | | | | | | | | - Elizeu Coutinho Macedo
- Social and Cognitive Neuroscience Laboratory, Developmental Disorders Program, Center for Health and Biological Sciences, Mackenzie Presbyterian University, São Paulo, Brazil
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11
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Wu Y, Cheng Y, Yang X, Yu W, Wan Y. Dyslexia: A Bibliometric and Visualization Analysis. Front Public Health 2022; 10:915053. [PMID: 35812514 PMCID: PMC9260156 DOI: 10.3389/fpubh.2022.915053] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/24/2022] [Indexed: 12/04/2022] Open
Abstract
Dyslexia is a disorder characterized by an impaired ability to understand written and printed words or phrases. Epidemiological longitudinal data show that dyslexia is highly prevalent, affecting 10-20% of the population regardless of gender. This study aims to provide a detailed overview of research status and development characteristics of dyslexia from types of articles, years, countries, institutions, journals, authors, author keywords, and highly cited papers. A total of 9,166 publications have been retrieved from the Social Sciences Citation Index (SSCI) and Science Citation Index Expanded (SCI-E) from 2000 to 2021. The United States of America, United Kingdom, and Germany were the top three most productive countries in terms of the number of publications. China, Israel, and Japan led the Asia research on dyslexia. University of Oxford had the most publications and won first place in terms of h-index. Dyslexia was the most productive journal in this field and Psychology was the most used subject category. Keywords analysis indicated that "developmental dyslexia," "phonological awareness," children and fMRI were still the main research topics. "Literacy," "rapid automatized naming (RAN)," "assessment," "intervention," "meta-analysis," "Chinese," "executive function," "morphological awareness," "decoding," "dyscalculia," "EEG," "Eye tracking," "rhythm," "bilingualism," and "functional connectivity" might become the new research hotspots.
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Affiliation(s)
- Yanqi Wu
- Institute of Information Resource, Zhejiang University of Technology, Hangzhou, China
- Library, Zhejiang University of Technology, Hangzhou, China
| | - Yanxia Cheng
- Institute of Information Resource, Zhejiang University of Technology, Hangzhou, China
- Library, Zhejiang University of Technology, Hangzhou, China
| | - Xianlin Yang
- Institute of Information Resource, Zhejiang University of Technology, Hangzhou, China
- Library, Zhejiang University of Technology, Hangzhou, China
| | - Wenyan Yu
- Library, Zhejiang University of Technology, Hangzhou, China
| | - Yuehua Wan
- Institute of Information Resource, Zhejiang University of Technology, Hangzhou, China
- Library, Zhejiang University of Technology, Hangzhou, China
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12
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Lasnick O, Feng J, Quirion A, Hart S, Hoeft F. The Importance of Family History in Dyslexia. THE READING LEAGUE JOURNAL 2022; 3:35-42. [PMID: 37384069 PMCID: PMC10306169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
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13
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Perrino PA, Chasse RY, Monaco AP, Molnár Z, Velayos‐Baeza A, Fitch RH. Rapid auditory processing and medial geniculate nucleus anomalies in Kiaa0319 knockout mice. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12808. [PMID: 35419947 PMCID: PMC9744489 DOI: 10.1111/gbb.12808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 03/23/2022] [Accepted: 03/31/2022] [Indexed: 11/29/2022]
Abstract
Developmental dyslexia is a common neurodevelopmental disorder characterized by difficulties in reading and writing. Although underlying biological and genetic mechanisms remain unclear, anomalies in phonological processing and auditory processing have been associated with dyslexia. Several candidate risk genes have also been identified, with KIAA0319 as a main candidate. Animal models targeting the rodent homolog (Kiaa0319) have been used to explore putative behavioral and anatomic anomalies, with mixed results. For example after downregulation of Kiaa0319 expression in rats via shRNA, significant adult rapid auditory processing impairments were reported, along with cortical anomalies reflecting atypical neuronal migration. Conversely, Kiaa0319 knockout (KO) mice were reported to have typical adult auditory processing, and no visible cortical anomalies. To address these inconsistencies, we tested Kiaa0319 KO mice on auditory processing tasks similar to those used previously in rat shRNA knockdown studies. Subsequent neuroanatomic analyses on these same mice targeted medial geniculate nucleus (MGN), a receptive communication-related brain structure. Results confirm that Kiaa0319 KO mice exhibit significant auditory processing impairments specific to rapid/brief stimuli, and also show significant volumetric reductions and a shift toward fewer large and smaller neurons in the MGN. The latter finding is consistent with post mortem MGN data from human dyslexic brains. Combined evidence supports a role for KIAA0319 in the development of auditory CNS pathways subserving rapid auditory processing functions critical to the development of speech processing, language, and ultimately reading. Results affirm KIAA0319 variation as a possible risk factor for dyslexia specifically via anomalies in central acoustic processing pathways.
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Affiliation(s)
- Peter A. Perrino
- Department of Psychological Science/Behavioral NeuroscienceUniversity of ConnecticutStorrsConnecticutUSA
| | - Renee Y. Chasse
- Department of Psychological Science/Behavioral NeuroscienceUniversity of ConnecticutStorrsConnecticutUSA
| | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
| | - Antonio Velayos‐Baeza
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK,Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - R. Holly Fitch
- Department of Psychological Science/Behavioral NeuroscienceUniversity of ConnecticutStorrsConnecticutUSA
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14
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Later but Not Weaker: Neural Categorization of Native Vowels of Children at Familial Risk of Dyslexia. Brain Sci 2022; 12:brainsci12030412. [PMID: 35326368 PMCID: PMC8946763 DOI: 10.3390/brainsci12030412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/11/2022] [Accepted: 03/11/2022] [Indexed: 02/04/2023] Open
Abstract
Although allophonic speech processing has been hypothesized to be a contributing factor in developmental dyslexia, experimental evidence is limited and inconsistent. The current study compared the categorization of native similar sounding vowels of typically developing (TD) children and children at familial risk (FR) of dyslexia. EEG response was collected in a non-attentive passive oddball paradigm from 35 TD and 35 FR Dutch 20-month-old infants who were matched on vocabulary. The children were presented with two nonwords “giep” [ɣip] and “gip” [ɣIp] that contrasted solely with respect to the vowel. In the multiple-speaker condition, both nonwords were produced by twelve different speakers while in the single-speaker condition, single tokens of each word were used as stimuli. For both conditions and for both groups, infant positive mismatch response (p-MMR) was elicited, and the p-MMR amplitude was comparable between the two groups, although the FR children had a later p-MMR peak than the TD children in the multiple-speaker condition. These findings indicate that FR children are able to categorize speech sounds, but that they may do so in a more effortful way than TDs.
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15
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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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16
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Bülbül T, Baharlooie M, Safaeinejad Z, Gure AO, Ghaedi K. Hypothetical molecular interconnection between type 2 diabetes and dyslexia. BMC Neurosci 2021; 22:63. [PMID: 34674647 PMCID: PMC8529849 DOI: 10.1186/s12868-021-00666-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 10/05/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Dyslexia is one of the most common learning disabilities, especially among children. Type 2 diabetes is a metabolic disorder that affects a large population globally, with metabolic disorders. There have been several genes that are identified as causes of Dyslexia, and in recent studies, it has been found out that some of those genes are also involved in several metabolic pathways. For several years, it has been known that type 2 diabetes causes several neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. Furthermore, in several studies, it was suggested that type 2 diabetes also has some associations with learning disabilities. This raises the question of whether "Is there a connection between type 2 diabetes and dyslexia?". In this study, this question is elaborated by linking their developmental processes via bioinformatics analysis about these two diseases individually and collectively. RESULT The literature review for dyslexia and type two diabetes was completed. As the result of this literature review, the genes that are associated to type 2 diabetes and dyslexia were identified. The biological pathways of dyslexia, and dyslexia associated genes, type 2 diabetes, and type 2 diabetes associated genes were identified. The association of these genes, regarding to their association with pathways were analysed, and using STRING database the gene associations were analysed and identified. CONCLUSION The findings of this research included the interaction analysis via gene association, co-expression and protein-protein interaction. These findings clarified the interconnection between dyslexia and type 2 diabetes in molecular level and it will be the beginning of an answer regarding to the relationship between T2D and dyslexia. Finally, by improving the understanding this paper aims to open the way for the possible future approach to examine this hypothesis.
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Affiliation(s)
- Tuğba Bülbül
- Department of Biomedical Sciences, Faculty of Health and Life Sciences, Coventry University, Coventry, West Midlands, UK
- Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara, Turkey
| | - Maryam Baharlooie
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Hezar Jerib Avenue, Azadi Sq., P.O.Code 81746-73441, Isfahan, Iran
| | - Zahra Safaeinejad
- Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Ali Osmay Gure
- Department of Medical Biology, Acibadem University, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara, Turkey
| | - Kamran Ghaedi
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Hezar Jerib Avenue, Azadi Sq., P.O.Code 81746-73441, Isfahan, Iran.
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17
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Kim SK. Recent update on reading disability (dyslexia) focused on neurobiology. Clin Exp Pediatr 2021; 64:497-503. [PMID: 33677854 PMCID: PMC8498014 DOI: 10.3345/cep.2020.01543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 01/21/2021] [Indexed: 01/10/2023] Open
Abstract
Reading disability (dyslexia) refers to an unexpected difficulty with reading for an individual who has the intelligence to be a much better reader. Dyslexia is most commonly caused by a difficulty in phonological processing (the appreciation of the individual sounds of spoken language), which affects the ability of an individual to speak, read, and spell. In this paper, I describe reading disabilities by focusing on their underlying neurobiological mechanisms. Neurobiological studies using functional brain imaging have uncovered the reading pathways, brain regions involved in reading, and neurobiological abnormalities of dyslexia. The reading pathway is in the order of visual analysis, letter recognition, word recognition, meaning (semantics), phonological processing, and speech production. According to functional neuroimaging studies, the important areas of the brain related to reading include the inferior frontal cortex (Broca's area), the midtemporal lobe region, the inferior parieto-temporal area, and the left occipitotemporal region (visual word form area). Interventions for dyslexia can affect reading ability by causing changes in brain function and structure. An accurate diagnosis and timely specialized intervention are important in children with dyslexia. In cases in which national infant development screening tests have been conducted, as in Korea, if language developmental delay and early predictors of dyslexia are detected, careful observation of the progression to dyslexia and early intervention should be made.
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Affiliation(s)
- Sung Koo Kim
- Department of Pediatrics, Hallym University Dongtan Sacred Heart Hospital, Hallym University College of Medicine, Hwaseong, Korea
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18
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Ostertag C, Reynolds JE, Dewey D, Landman B, Huo Y, Lebel C. Altered gray matter development in pre-reading children with a family history of reading disorder. Dev Sci 2021; 25:e13160. [PMID: 34278658 DOI: 10.1111/desc.13160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 12/23/2022]
Abstract
Reading disorders are common in children and can impact academic success, mental health, and career prospects. Reading is supported by network of interconnected left hemisphere brain regions, including temporo-parietal, occipito-temporal, and inferior-frontal circuits. Poor readers often show hypoactivation and reduced gray matter volumes in this reading network, with hyperactivation and increased volumes in the posterior right hemisphere. We assessed gray matter development longitudinally in pre-reading children aged 2-5 years using magnetic resonance imaging (MRI) (N = 32, 110 MRI scans; mean age: 4.40 ± 0.77 years), half of whom had a family history of reading disorder. The family history group showed slower proportional growth (relative to total brain volume) in the left supramarginal and inferior frontal gyri, and faster proportional growth in the right angular, right fusiform, and bilateral lingual gyri. This suggests delayed development of left hemisphere reading areas in children with a family history of dyslexia, along with faster growth in right homologues. This alternate development pattern may predispose the brain to later reading difficulties and may later manifest as the commonly noted compensatory mechanisms. The results of this study further shows our understanding of structural brain alterations that may form the neurological basis of reading difficulties.
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Affiliation(s)
- Curtis Ostertag
- Department of Radiology, University of Calgary, Calgary, AB, Canada.,Owerko Centre, Alberta Children Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Jess E Reynolds
- Department of Radiology, University of Calgary, Calgary, AB, Canada.,Owerko Centre, Alberta Children Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Deborah Dewey
- Owerko Centre, Alberta Children Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Pediatrics, University of Calgary, Calgary, AB, Canada.,Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada
| | - Bennett Landman
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Yuankai Huo
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Catherine Lebel
- Department of Radiology, University of Calgary, Calgary, AB, Canada.,Owerko Centre, Alberta Children Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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19
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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: 11] [Impact Index Per Article: 3.7] [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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20
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The Polygenic Nature and Complex Genetic Architecture of Specific Learning Disorder. Brain Sci 2021; 11:brainsci11050631. [PMID: 34068951 PMCID: PMC8156942 DOI: 10.3390/brainsci11050631] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/16/2022] Open
Abstract
Specific Learning Disorder (SLD) is a multifactorial, neurodevelopmental disorder which may involve persistent difficulties in reading (dyslexia), written expression and/or mathematics. Dyslexia is characterized by difficulties with speed and accuracy of word reading, deficient decoding abilities, and poor spelling. Several studies from different, but complementary, scientific disciplines have investigated possible causal/risk factors for SLD. Biological, neurological, hereditary, cognitive, linguistic-phonological, developmental and environmental factors have been incriminated. Despite worldwide agreement that SLD is highly heritable, its exact biological basis remains elusive. We herein present: (a) an update of studies that have shaped our current knowledge on the disorder’s genetic architecture; (b) a discussion on whether this genetic architecture is ‘unique’ to SLD or, alternatively, whether there is an underlying common genetic background with other neurodevelopmental disorders; and, (c) a brief discussion on whether we are at a position of generating meaningful correlations between genetic findings and anatomical data from neuroimaging studies or specific molecular/cellular pathways. We conclude with open research questions that could drive future research directions.
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21
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Thomas T, Perdue MV, Khalaf S, Landi N, Hoeft F, Pugh K, Grigorenko EL. Neuroimaging genetic associations between SEMA6D, brain structure, and reading skills. J Clin Exp Neuropsychol 2021; 43:276-289. [PMID: 33960276 PMCID: PMC8225580 DOI: 10.1080/13803395.2021.1912300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/30/2021] [Indexed: 01/15/2023]
Abstract
Specific reading disability (SRD) is defined by genetic and neural risk factors that are not fully understood. The current study used imaging genetics methodology to investigate relationships between SEMA6D, brain structure, and reading. SEMA6D, located on SRD risk locus DYX1, is involved in axon guidance, synapse formation, and dendrite development. SEMA6D's associations with brain structure in reading-related regions of interest (ROIs) were investigated in a sample of children with a range of reading performance, from sites in Connecticut, CT (n = 67, 6-13 years, mean age = 9.07) and San Francisco, SF (n = 28, 5-8 years, mean age = 6.5). Multiple regression analyses revealed significant associations between SEMA6D's rs16959669 and cortical thickness in the fusiform gyrus and rs4270119 and gyrification in the supramarginal gyrus in the CT sample, but this was not replicated in the SF sample. Significant clusters were not associated with reading. For white matter volume, combined analyses across both samples revealed associations between reading and the left transverse temporal gyrus, left pars triangularis, left cerebellum, and right cerebellum. White matter volume in the left transverse temporal gyrus was nominally related to rs1817178, rs12050859, and rs1898110 in SEMA6D, and rs1817178 was significantly related to reading. Haplotype analyses revealed significant associations between the whole gene and brain phenotypes. Results suggest SEMA6D likely has an impact on multiple reading-related neural structures, but only white matter volume in the transverse temporal gyrus was significantly related to reading in the current sample. As the sample was young, the transverse temporal gyrus, involved in auditory perception, may be more strongly involved in reading because phonological processing is still being learned. The relationship between SEMA6D and reading may change as different brain regions are involved during reading development. Future research should examine mediating effects, use additional brain measures, and use an older sample to better understand effects.
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Affiliation(s)
- Tina Thomas
- Department of Psychology, University of Houston, Houston, TX, USA
| | - Meaghan V. Perdue
- University of Connecticut Dept. of Psychological Sciences, Storrs, CT, USA
- Haskins Laboratories, University of Connecticut, New Haven, CT, USA
| | - Shiva Khalaf
- Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA
| | - Nicole Landi
- University of Connecticut Dept. of Psychological Sciences, Storrs, CT, USA
- Haskins Laboratories, University of Connecticut, New Haven, CT, USA
| | - Fumiko Hoeft
- University of Connecticut Dept. of Psychological Sciences, Storrs, CT, USA
- Department of Psychiatry, University of California, San Francisco, CA, USA
| | - Kenneth Pugh
- University of Connecticut Dept. of Psychological Sciences, Storrs, CT, USA
- Haskins Laboratories, University of Connecticut, New Haven, CT, USA
| | - Elena L. Grigorenko
- Department of Psychology, University of Houston, Houston, TX, USA
- Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, Houston, TX, USA
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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22
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Romanovska L, Janssen R, Bonte M. Cortical responses to letters and ambiguous speech vary with reading skills in dyslexic and typically reading children. NEUROIMAGE-CLINICAL 2021; 30:102588. [PMID: 33618236 PMCID: PMC7907898 DOI: 10.1016/j.nicl.2021.102588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/26/2021] [Accepted: 02/02/2021] [Indexed: 11/25/2022]
Abstract
Text recalibrates ambiguous speech perception in children with and without dyslexia. Dyslexia and poorer reading skills are linked to reduced left fusiform activation. Poorer letter-speech sound matching is linked to higher superior temporal activation.
One of the proposed issues underlying reading difficulties in dyslexia is insufficiently automatized letter-speech sound associations. In the current fMRI experiment, we employ text-based recalibration to investigate letter-speech sound mappings in 8–10 year-old children with and without dyslexia. Here an ambiguous speech sound /a?a/ midway between /aba/ and /ada/ is combined with disambiguating “aba” or “ada” text causing a perceptual shift of the ambiguous /a?a/ sound towards the text (recalibration). This perceptual shift has been found to be reduced in adults but not in children with dyslexia compared to typical readers. Our fMRI results show significantly reduced activation in the left fusiform in dyslexic compared to typical readers, despite comparable behavioural performance. Furthermore, enhanced audio-visual activation within this region was linked to better reading and phonological skills. In contrast, higher activation in bilateral superior temporal cortex was associated with lower letter-speech sound identification fluency. These findings reflect individual differences during the early stages of reading development with reduced recruitment of the left fusiform in dyslexic readers together with an increased involvement of the superior temporal cortex in children with less automatized letter-speech sound associations.
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Affiliation(s)
- Linda Romanovska
- Maastricht Brain Imaging Center, Department Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.
| | - Roef Janssen
- Maastricht Brain Imaging Center, Department Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Milene Bonte
- Maastricht Brain Imaging Center, Department Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
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23
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Grimm T, Garshasbi M, Puettmann L, Chen W, Ullmann R, Müller-Myhsok B, Klopocki E, Herbst L, Haug J, Jensen LR, Fischer C, Nöthen M, Ludwig K, Warnke A, Ott J, Schulte-Körne G, Ropers HH, Kuss AW. A Novel Locus and Candidate Gene for Familial Developmental Dyslexia on Chromosome 4q. ZEITSCHRIFT FUR KINDER-UND JUGENDPSYCHIATRIE UND PSYCHOTHERAPIE 2020; 48:478-489. [PMID: 33172359 DOI: 10.1024/1422-4917/a000758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Objective: Developmental dyslexia is a highly heritable specific reading and writing disability. To identify a possible new locus and candidate gene for this disability, we investigated a four-generation pedigree where transmission of dyslexia is consistent with an autosomal dominant inheritance pattern. Methods: We performed genome wide array-based SNP genotyping and parametric linkage analysis and sequencing analysis of protein-coding exons, exon-intron boundaries and conserved extragenic regions within the haplotype cosegregating with dyslexia in DNA from one affected and one unaffected family member. Cosegregation was confirmed by sequencing all available family members. Additionally, we analyzed 96 dyslexic individuals who had previously shown positive LOD scores on chromosome 4q28 as well as an even larger sample (n = 2591). Results: We found a single prominent linkage interval on chromosome 4q, where sequence analysis revealed a nucleotide variant in the 3' UTR of brain expressed SPRY1 in the dyslexic family member that cosegregated with dyslexia. This sequence alteration might affect the binding efficiency of the IGF2BP1 RNA-binding protein and thus influence the expression level of the SPRY1 gene product. An analysis of 96 individuals from a cohort of dyslexic individuals revealed a second heterozygous variant in this gene, which was absent in the unaffected sister of the proband. An investigation of the region in a much larger sample further found a nominal p-value of 0.0016 for verbal short-term memory (digit span) in 2,591 individuals for a neighboring SNV. After correcting for the local number of analyzed SNVs, and after taking into account linkage disequilibrium, we found this corresponds to a p-value of 0.0678 for this phenotype. Conclusions: We describe a new locus for familial dyslexia and discuss the possibility that SPRY1 might play a role in the etiology of a monogenic form of dyslexia.
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Affiliation(s)
- Tiemo Grimm
- Department of Human Genetics, Biozentrum, University of Würzburg, Germany
| | - Masoud Garshasbi
- Department for Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Lucia Puettmann
- Department for Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Wei Chen
- Department for Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Reinhard Ullmann
- Department for Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | | | - Eva Klopocki
- Department of Human Genetics, Biozentrum, University of Würzburg, Germany
| | - Lina Herbst
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Janina Haug
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Lars R Jensen
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | | | - Markus Nöthen
- Institute of Human Genetics, University of Bonn, Germany
| | - Kerstin Ludwig
- Institute of Human Genetics, University of Bonn, Germany
| | - Andreas Warnke
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Würzburg, Germany
| | - Jürg Ott
- Laboratory of Statistical Genetics, Rockefeller University, New York, USA
| | - Gerd Schulte-Körne
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Munich, Germany
| | - Hans-Hilger Ropers
- Department for Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Andreas W Kuss
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Germany
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24
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Conant LL, Liebenthal E, Desai A, Seidenberg MS, Binder JR. Differential activation of the visual word form area during auditory phoneme perception in youth with dyslexia. Neuropsychologia 2020; 146:107543. [PMID: 32598966 DOI: 10.1016/j.neuropsychologia.2020.107543] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/16/2020] [Accepted: 06/21/2020] [Indexed: 12/12/2022]
Abstract
Developmental dyslexia is a learning disorder characterized by difficulties reading words accurately and/or fluently. Several behavioral studies have suggested the presence of anomalies at an early stage of phoneme processing, when the complex spectrotemporal patterns in the speech signal are analyzed and assigned to phonemic categories. In this study, fMRI was used to compare brain responses associated with categorical discrimination of speech syllables (P) and acoustically matched nonphonemic stimuli (N) in children and adolescents with dyslexia and in typically developing (TD) controls, aged 8-17 years. The TD group showed significantly greater activation during the P condition relative to N in an area of the left ventral occipitotemporal cortex that corresponds well with the region referred to as the "visual word form area" (VWFA). Regression analyses using reading performance as a continuous variable across the full group of participants yielded similar results. Overall, the findings are consistent with those of previous neuroimaging studies using print stimuli in individuals with dyslexia that found reduced activation in left occipitotemporal regions; however, the current study shows that these activation differences seen during reading are apparent during auditory phoneme discrimination in youth with dyslexia, suggesting that the primary deficit in at least a subset of children may lie early in the speech processing stream and that categorical perception may be an important target of early intervention in children at risk for dyslexia.
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Affiliation(s)
- Lisa L Conant
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Einat Liebenthal
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Psychiatry, McLean Hospital, Harvard Medical School, Boston, MA, USA
| | - Anjali Desai
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Mark S Seidenberg
- Department of Psychology, University of Wisconsin-Madison, Madison, WI, USA
| | - Jeffrey R Binder
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
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25
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Balestra S, Eugster B, Liebert H. Summer-born struggle: The effect of school starting age on health, education, and work. HEALTH ECONOMICS 2020; 29:591-607. [PMID: 32052533 PMCID: PMC9328428 DOI: 10.1002/hec.4005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 01/07/2020] [Accepted: 01/20/2020] [Indexed: 06/10/2023]
Abstract
Children starting school older consistently exhibit better educational outcomes. In this paper, we underscore child development as a mechanism driving this effect. Using unique administrative data on health examinations, we study the causal effect of school starting age (SSA) on a child's probability of being diagnosed with special educational needs in early grades. Results show that children with higher SSA are less likely to develop behavioral problems and speech impediments, whereas learning disabilities, ADHD, and dyslexia/dyscalculia remain unaffected. Importantly, these effects only arise after primary school entry and are not due to preexisting health conditions. We also find that teachers tend to over-refer relatively young children to special needs services, but this over-referring behavior is not driving the results, which are based on psychologists' diagnoses. The SSA effect persists throughout compulsory schooling, resulting in higher test scores and better quality vocational training contracts. However, SSA does not affect employment, earnings, or disability insurance benefits at labor market entry.
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Affiliation(s)
- Simone Balestra
- Center for Disability and Integration, Department of EconomicsUniversity of St. GallenSt. GallenSwitzerland
| | - Beatrix Eugster
- Center for Disability and Integration, Department of EconomicsUniversity of St. GallenSt. GallenSwitzerland
| | - Helge Liebert
- Department of Health Care PolicyHarvard Medical School, Harvard UniversityCambridgeMassachusetts
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Jiménez EC, Romeo A, Pérez Zapata L, Solé Puig M, Bustos-Valenzuela P, Cañete J, Varela Casal P, Supèr H. Eye vergence responses in children with and without reading difficulties during a word detection task. Vision Res 2020; 169:6-11. [PMID: 32143068 DOI: 10.1016/j.visres.2020.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 01/31/2020] [Accepted: 02/12/2020] [Indexed: 12/21/2022]
Abstract
Vergence eye movements are movements of both eyes in opposite directions. Vergence is known to have a role in binocular vision. However recent studies link vergence eye movements also to attention and attention disorders. As attention may be involved in dyslexia, it is sensible to guess that the presence of reading difficulties can be associated with specific patterns in vergence responses. Data from school children performing a word-reading task have been analysed. In the task, children had to distinguish words from non-words (scrambled words or row of X's), while their eye positions were recorded. Our findings show that after stimulus presentation eyes briefly converge. These vergence responses depend on the stimulus type and age of the child, and are different for children with reading difficulties. Our findings support the idea of a role of attention in word reading and offer an explanation of altered attention in dyslexia.
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Affiliation(s)
- Elizabeth Carolina Jiménez
- Dept. of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain; Institute of Neurosciences of the University of Barcelona (UBNeuro), Barcelona, Spain; University of Guadalajara, Jalisco, Mexico
| | - August Romeo
- Dept. of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain; Braingaze SL, Mataró, Spain
| | - Laura Pérez Zapata
- Projecte UBinding, Unitat de Trastorns del Desenvolupament. Universitat de Barcelona, Fundació Josep Finestres, Barcelona, Spain
| | - Maria Solé Puig
- Dept. of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain
| | | | - José Cañete
- Departamento de Psiquiatría del Hospital de Mataró, Mataró, Spain
| | - Paloma Varela Casal
- Departamento de Psiquiatría del Hospital de Mataró, Mataró, Spain; Dept of Psychiatry and Forensic Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Hans Supèr
- Dept. of Cognition, Development and Educational Psychology, University of Barcelona, Barcelona, Spain; Institute of Neurosciences of the University of Barcelona (UBNeuro), Barcelona, Spain; Braingaze SL, Mataró, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain.
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Khalid M, Anjum G. Use of remedial teaching approaches for dyslexic students: Experiences of remedial teachers working in urban Pakistan. COGENT PSYCHOLOGY 2019. [DOI: 10.1080/23311908.2019.1580181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
| | - Gulnaz Anjum
- Department of Social Sciences and Liberal arts, Institute of Business Administration, IBA, Karachi, Pakistan
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28
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Neurobiological systems in dyslexia. Trends Neurosci Educ 2019; 14:11-24. [DOI: 10.1016/j.tine.2018.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 09/13/2018] [Accepted: 12/12/2018] [Indexed: 12/12/2022]
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Krafnick AJ, Evans TM. Neurobiological Sex Differences in Developmental Dyslexia. Front Psychol 2019; 9:2669. [PMID: 30687153 PMCID: PMC6336691 DOI: 10.3389/fpsyg.2018.02669] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 12/12/2018] [Indexed: 12/13/2022] Open
Abstract
Understanding sex differences at the neurobiological level has become increasingly crucial in both basic and applied research. In the study of developmental dyslexia, early neuroimaging investigations were dominated by male-only or male-dominated samples, due at least in part to males being diagnosed more frequently. While recent studies more consistently balance the inclusion of both sexes, there has been little movement toward directly characterizing potential sex differences of the disorder. However, a string of recent work suggests that the brain basis of dyslexia may indeed be different in males and females. This potential sex difference has implications for existing models of dyslexia, and would inform approaches to the remediation of reading difficulties. This article reviews recent evidence for sex differences in dyslexia, discusses the impact these studies have on the understanding of the brain basis of dyslexia, and provides a framework for how these differential neuroanatomical profiles may develop.
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Affiliation(s)
- Anthony J Krafnick
- Psychology Department, Dominican University, River Forest, IL, United States
| | - Tanya M Evans
- Center for Advanced Study of Teaching and Learning, Curry School of Education and Human Development, University of Virginia, Charlottesville, VA, United States
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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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32
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McDowell M. Specific learning disability. J Paediatr Child Health 2018; 54:1077-1083. [PMID: 30294983 DOI: 10.1111/jpc.14168] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 07/04/2018] [Indexed: 12/24/2022]
Abstract
Specific learning disabilities (SLD) have an impact on discrete areas of academic function. They result in a level of difficulty that is unexpected when considered in the context of a student's overall intellectual and academic competence. A common example is dyslexia, an SLD that affects the acquisition of literacy. Medical professionals have an important role to play in the evaluation and management of SLD. The medical role is founded on the fact that these conditions are biologically based and have the potential to cause significant harm for the developing child. Even if details of biological causation are not possible to demonstrate for individual children, medical professionals may, nevertheless, make an important judgement call regarding the likelihood of aetiology. When learning problems are medically based, it is clearly unreasonable to expect children to do more than they are able and to learn faster than is reasonable. Advocacy around these biological presumptions and their implications is a major contribution to the well-being of children who have SLD.
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Affiliation(s)
- Michael McDowell
- School of Medicine, University of Queensland, Brisbane, Queensland, Australia.,Child Development Network, Brisbane, Queensland, Australia.,Neurodevelopmental and Behavioural Paediatric Society of Australasia (https://nbpsa.org/)
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Peyre H, Gérard CL, Dupong Vanderhorst I, Larger S, Lemoussu C, Vesta J, Bui Quoc E, Gouleme N, Delorme R, Bucci M. Rééducation oculomotrice informatisée dans la dyslexie : essai clinique randomisé en crossover en population pédiatrique. Encephale 2018; 44:247-255. [DOI: 10.1016/j.encep.2017.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 03/11/2017] [Accepted: 03/13/2017] [Indexed: 11/16/2022]
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Child AE, Cirino PT, Fletcher JM, Willcutt EG, Fuchs LS. A Cognitive Dimensional Approach to Understanding Shared and Unique Contributions to Reading, Math, and Attention Skills. JOURNAL OF LEARNING DISABILITIES 2018; 52:15-30. [PMID: 29779434 PMCID: PMC6212329 DOI: 10.1177/0022219418775115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Disorders of reading, math, and attention frequently co-occur in children. However, it is not yet clear which cognitive factors contribute to comorbidities among multiple disorders and which uniquely relate to one, especially because they have rarely been studied as a triad. Thus, the present study considers how reading, math, and attention relate to phonological awareness, numerosity, working memory, and processing speed, all implicated as either unique or shared correlates of these disorders. In response to findings that the attributes of all three disorders exist on a continuum rather than representing qualitatively different groups, this study employed a dimensional approach. Furthermore, we used both timed and untimed academic variables in addition to attention and activity level variables. The results supported the role of working memory and phonological awareness in the overlap among reading, math, and attention, with a limited role of processing speed. Numerosity was related to the comorbidity between math and attention. The results from timed variables and activity level were similar to those from untimed and attention variables, although activity level was less strongly related to cognitive and academic/attention variables. These findings have implications for understanding cognitive deficits that contribute to comorbid reading disability, math disability, and/or attention-deficit/hyperactivity disorder.
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Affiliation(s)
| | | | | | - Erik G. Willcutt
- Department of Psychology and Neuroscience, University of Colorado
| | - Lynn S. Fuchs
- Department of Special Education, Vanderbilt University
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Rendall AR, Perrino PA, LoTurco JJ, Fitch RH. Evaluation of visual motion perception ability in mice with knockout of the dyslexia candidate susceptibility gene Dcdc2. GENES BRAIN AND BEHAVIOR 2018; 18:e12450. [PMID: 29232042 DOI: 10.1111/gbb.12450] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 12/08/2017] [Accepted: 12/08/2017] [Indexed: 12/17/2022]
Abstract
Developmental dyslexia is a heritable disability characterized by difficulties in learning to read and write. The neurobiological and genetic mechanisms underlying dyslexia remain poorly understood; however, several dyslexia candidate risk genes have been identified. One of these candidate risk genes-doublecortin domain containing 2 (DCDC2)-has been shown to play a role in neuronal migration and cilia function. At a behavioral level, variants of DCDC2 have been associated with impairments in phonological processing, working memory and reading speed. Additionally, a specific mutation in DCDC2 has been strongly linked to deficits in motion perception-a skill subserving reading abilities. To further explore the relationship between DCDC2 and dyslexia, a genetic knockout (KO) of the rodent homolog of DCDC2 (Dcdc2) was created. Initial studies showed that Dcdc2 KOs display deficits in auditory processing and working memory. The current study was designed to evaluate the association between DCDC2 and motion perception, as these skills have not yet been assessed in the Dcdc2 KO mouse model. We developed a novel motion perception task, utilizing touchscreen technology and operant conditioning. Dcdc2 KOs displayed deficits on the Pairwise Discrimination task specifically as motion was added to visual stimuli. Following behavioral assessment, brains were histologically prepared for neuroanatomical analysis of the lateral geniculate nucleus (LGN). The cumulative distribution showed that Dcdc2 KOs exhibited more small neurons and fewer larger neurons in the LGN. Results compliment findings that DCDC2 genetic alteration results in anomalies in visual motion pathways in a subpopulation of dyslexic patients.
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Affiliation(s)
- A R Rendall
- Department of Psychology/Behavioral Neuroscience and Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
| | - P A Perrino
- Department of Psychology/Behavioral Neuroscience and Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
| | - J J LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - R H Fitch
- Department of Psychology/Behavioral Neuroscience and Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
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Ancestral Variations of the PCDHG Gene Cluster Predispose to Dyslexia in a Multiplex Family. EBioMedicine 2018; 28:168-179. [PMID: 29409727 PMCID: PMC5835549 DOI: 10.1016/j.ebiom.2017.12.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 12/22/2017] [Accepted: 12/28/2017] [Indexed: 12/15/2022] Open
Abstract
Dyslexia is a heritable neurodevelopmental disorder characterized by difficulties in reading and writing. In this study, we describe the identification of a set of 17 polymorphisms located across 1.9 Mb region on chromosome 5q31.3, encompassing genes of the PCDHG cluster, TAF7, PCDH1 and ARHGAP26, dominantly inherited with dyslexia in a multi-incident family. Strikingly, the non-risk form of seven variations of the PCDHG cluster, are preponderant in the human lineage, while risk alleles are ancestral and conserved across Neanderthals to non-human primates. Four of these seven ancestral variations (c.460A > C [p.Ile154Leu], c.541G > A [p.Ala181Thr], c.2036G > C [p.Arg679Pro] and c.2059A > G [p.Lys687Glu]) result in amino acid alterations. p.Ile154Leu and p.Ala181Thr are present at EC2: EC3 interacting interface of γA3-PCDH and γA4-PCDH respectively might affect trans-homophilic interaction and hence neuronal connectivity. p.Arg679Pro and p.Lys687Glu are present within the linker region connecting trans-membrane to extracellular domain. Sequence analysis indicated the importance of p.Ile154, p.Arg679 and p.Lys687 in maintaining class specificity. Thus the observed association of PCDHG genes encoding neural adhesion proteins reinforces the hypothesis of aberrant neuronal connectivity in the pathophysiology of dyslexia. Additionally, the striking conservation of the identified variants indicates a role of PCDHG in the evolution of highly specialized cognitive skills critical to reading. A set of seventeen common variations on chr5q31.3 co-segregate with dyslexia Ancestral risk forms are conserved throughoutNeanderthals to primates while non-risks are preponderant in modern humans p.Ile154Leu and p.Ala181Thr, present in interacting interface of EC2: EC3 Species specific isoform identity of p.Ile154Leu, p.Arg679Pro and p.Lys687Glu
Worldwide epidemiological data suggests that one in every ten children is affected with dyslexia which is an alarming number and possesses a serious burden on mental health. We identified single nucleotide variations on protocadherin gamma (PCDHG) gene cluster co-segregate with dyslexia in a multiincident family. The described variants present on the interacting domain of protocadherin gamma reiterates the underlying dysregulated functional connectivity in dyslexia pathophysiology. This finding may help toward understanding the basic molecular mechanisms of dyslexia, and may help in identifying points of therapeutic intervention.
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Tzeng OJL, Lee CY, Lee JR, Wu DH, Lee RRW, Hung DL. Neurolinguistic Studies of Reading in Chinese. New Dir Child Adolesc Dev 2017; 2017:55-68. [DOI: 10.1002/cad.20219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ovid J. L. Tzeng
- National Chiao Tung University, Taipei Medical University, and National Taiwan Normal University
| | | | | | | | | | - Daisy L. Hung
- National Central University & Taipei Medical University
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Rendall AR, Tarkar A, Contreras-Mora HM, LoTurco JJ, Fitch RH. Deficits in learning and memory in mice with a mutation of the candidate dyslexia susceptibility gene Dyx1c1. BRAIN AND LANGUAGE 2017; 172:30-38. [PMID: 25989970 PMCID: PMC4646737 DOI: 10.1016/j.bandl.2015.04.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/15/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
Dyslexia is a learning disability characterized by difficulty learning to read and write. The underlying biological and genetic etiology remains poorly understood. One candidate gene, dyslexia susceptibility 1 candidate 1 (DYX1C1), has been shown to be associated with deficits in short-term memory in dyslexic populations. The purpose of the current study was to examine the behavioral phenotype of a mouse model with a homozygous conditional (forebrain) knockout of the rodent homolog Dyx1c1. Twelve Dyx1c1 conditional homozygous knockouts, 7 Dyx1c1 conditional heterozygous knockouts and 6 wild-type controls were behaviorally assessed. Mice with the homozygous Dyx1c1 knockout showed deficits on memory and learning, but not on auditory or motor tasks. These findings affirm existing evidence that DYX1C1 may play an underlying role in the development of neural systems important to learning and memory, and disruption of this function could contribute to the learning deficits seen in individuals with dyslexia.
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Affiliation(s)
- Amanda R Rendall
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, United States.
| | - Aarti Tarkar
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, Unit 3156, Storrs, CT 06269, United States
| | - Hector M Contreras-Mora
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, United States
| | - Joseph J LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, Unit 3156, Storrs, CT 06269, United States
| | - R Holly Fitch
- Department of Psychology/Behavioral Neuroscience, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT 06269, United States
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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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Chen A, Wijnen F, Koster C, Schnack H. Individualized Early Prediction of Familial Risk of Dyslexia: A Study of Infant Vocabulary Development. Front Psychol 2017; 8:156. [PMID: 28270778 PMCID: PMC5318442 DOI: 10.3389/fpsyg.2017.00156] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 01/23/2017] [Indexed: 12/13/2022] Open
Abstract
We examined early vocabulary development in children at familial risk (FR) of dyslexia and typically developing (TD) children between 17 and 35 months of age. We trained a support vector machine to classify TD and FR using these vocabulary data at the individual level. The Dutch version of the McArthur-Bates Communicative Development Inventory (Words and Sentences) (N-CDI) was used to measure vocabulary development. We analyzed group-level differences for both total vocabulary as well as lexical classes: common nouns, predicates, and closed class words. The generalizability of the classification model was tested using cross-validation. At the group level, for both total vocabulary and the composites, the difference between TD and FR was most pronounced at 19-20 months, with FRs having lower scores. For the individual prediction, highest cross-validation accuracy (68%) was obtained at 19-20 months, with sensitivity (correctly classified FR) being 70% and specificity (correctly classified TD) being 67%. There is a sensitive window in which the difference between FR and TD is most evident. Machine learning methods are promising techniques for separating FR and TD children at an early age, before they start reading.
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Affiliation(s)
- Ao Chen
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, Netherlands; Utrecht Institute of Linguistics OTS, Utrecht UniversityUtrecht, Netherlands
| | - Frank Wijnen
- Utrecht Institute of Linguistics OTS, Utrecht University Utrecht, Netherlands
| | - Charlotte Koster
- Center for Language and Cognition Groningen, University of Groningen Groningen, Netherlands
| | - Hugo Schnack
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht Utrecht, Netherlands
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41
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Gilger JW, Bayda M, Olulade OA, Altman MN, O'Boyle M. Preliminary Report on Neuroanatomical Differences Among Reading Disabled, Nonverbally Gifted, and Gifted-Reading Disabled College Students. Dev Neuropsychol 2017; 42:25-38. [PMID: 28128987 DOI: 10.1080/87565641.2016.1256402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Regional comparisons (cortical surface area and thickness) were performed on a well described sample of adults with reading disability alone (RD), nonverbal giftedness alone (G), and reading disability and nonverbal giftedness combined (GRD). These anatomical results are considered in relation to behavioral and functional work previously reported on this sample. GRD-RD regional differences were found in both hemispheres and were more common than GRD-G differences. Regional differences were found in the temporal, parietal, occipital and frontal lobes. While these data are preliminary given the small sample sizes, they suggest future avenues of research on the neurodevelopment of atypical samples.
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Affiliation(s)
- Jeffrey W Gilger
- a Psychological Sciences , University of California , Merced , California
| | - Mollie Bayda
- b Department of Psychiatry , University of California , San Francisco , California
| | - Olumide A Olulade
- c Center for the Study of Learning , Georgetown University Medical Center , Washington , District of Columbia
| | - Meaghan N Altman
- a Psychological Sciences , University of California , Merced , California
| | - Michael O'Boyle
- d Department of Human Development and Family Studies , Texas Tech University , Lubbock , Texas
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42
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Neef NE, Müller B, Liebig J, Schaadt G, Grigutsch M, Gunter TC, Wilcke A, Kirsten H, Skeide MA, Kraft I, Kraus N, Emmrich F, Brauer J, Boltze J, Friederici AD. Dyslexia risk gene relates to representation of sound in the auditory brainstem. Dev Cogn Neurosci 2017; 24:63-71. [PMID: 28182973 PMCID: PMC6987796 DOI: 10.1016/j.dcn.2017.01.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/15/2017] [Accepted: 01/15/2017] [Indexed: 12/20/2022] Open
Abstract
Previous studies associate poor reading with unstable speech-evoked brainstem responses. DCDC2 and KIAA0319 risk alleles form a strong genetic link with developmental dyslexia. Genetic burden with KIAA0319 risk is related to unstable speech-evoked brainstem responses. Genetic burden with DCDC2 risk is related to intact speech-evoked brainstem responses. Revealed brain-gene relationships may inform the multifactorial pathophysiology of dyslexia.
Dyslexia is a reading disorder with strong associations with KIAA0319 and DCDC2. Both genes play a functional role in spike time precision of neurons. Strikingly, poor readers show an imprecise encoding of fast transients of speech in the auditory brainstem. Whether dyslexia risk genes are related to the quality of sound encoding in the auditory brainstem remains to be investigated. Here, we quantified the response consistency of speech-evoked brainstem responses to the acoustically presented syllable [da] in 159 genotyped, literate and preliterate children. When controlling for age, sex, familial risk and intelligence, partial correlation analyses associated a higher dyslexia risk loading with KIAA0319 with noisier responses. In contrast, a higher risk loading with DCDC2 was associated with a trend towards more stable responses. These results suggest that unstable representation of sound, and thus, reduced neural discrimination ability of stop consonants, occurred in genotypes carrying a higher amount of KIAA0319 risk alleles. Current data provide the first evidence that the dyslexia-associated gene KIAA0319 can alter brainstem responses and impair phoneme processing in the auditory brainstem. This brain-gene relationship provides insight into the complex relationships between phenotype and genotype thereby improving the understanding of the dyslexia-inherent complex multifactorial condition.
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Affiliation(s)
- Nicole E Neef
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany.
| | - Bent Müller
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany
| | - Johanna Liebig
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Gesa Schaadt
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany; Department of Psychology, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Maren Grigutsch
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Thomas C Gunter
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Arndt Wilcke
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany
| | - Holger Kirsten
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig and LIFE-Leipzig Research Center for Civilization Diseases, University of Leipzig, Germany
| | - Michael A Skeide
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Indra Kraft
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Nina Kraus
- Auditory Neuroscience Laboratory, Northwestern University, Evanston, IL 60208, USA
| | - Frank Emmrich
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany
| | - Jens Brauer
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
| | - Johannes Boltze
- Department of Cell Therapy, Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany; Department of Medical Cell Technology, Fraunhofer Research Institution for Marine Biotechnology, and Institute for Medical and Marine Biotechnology, University of Lübeck, Germany
| | - Angela D Friederici
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany
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Kong R, Song RR. [Research advances in susceptible genes for developmental dyslexia in children]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2016; 18:1308-1312. [PMID: 27974128 PMCID: PMC7403085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/24/2016] [Indexed: 12/16/2023]
Abstract
Developmental dyslexia in children is one of the neurodevelopmental disorders and is affected by various susceptible genes. In recent years, researchers have found some susceptible genes for dyslexia via chromosome analysis, genome-wide association studies, association analysis, gene function research, neuroimaging, and neurophysiological techniques. This article reviews the research advances in susceptible genes for developmental dyslexia, and with the study on susceptible genes for dyslexia, it lays a foundation for in-depth studies on the "gene-brain-behavior" level and provides scientific clues for exploring etiology and pathogenesis of dyslexia.
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Affiliation(s)
- Rui Kong
- Department of Maternal and Child Health Care, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Kong R, Song RR. [Research advances in susceptible genes for developmental dyslexia in children]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2016; 18:1308-1312. [PMID: 27974128 PMCID: PMC7403085 DOI: 10.7499/j.issn.1008-8830.2016.12.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Developmental dyslexia in children is one of the neurodevelopmental disorders and is affected by various susceptible genes. In recent years, researchers have found some susceptible genes for dyslexia via chromosome analysis, genome-wide association studies, association analysis, gene function research, neuroimaging, and neurophysiological techniques. This article reviews the research advances in susceptible genes for developmental dyslexia, and with the study on susceptible genes for dyslexia, it lays a foundation for in-depth studies on the "gene-brain-behavior" level and provides scientific clues for exploring etiology and pathogenesis of dyslexia.
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Affiliation(s)
- Rui Kong
- Department of Maternal and Child Health Care, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Gilger JW, Allen K, Castillo A. Reading disability and enhanced dynamic spatial reasoning: A review of the literature. Brain Cogn 2016; 105:55-65. [DOI: 10.1016/j.bandc.2016.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 03/19/2016] [Accepted: 03/22/2016] [Indexed: 11/24/2022]
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Alanazi MA, Alanazi SA, Osuagwu UL. Evaluation of visual stress symptoms in age-matched dyslexic, Meares-Irlen syndrome and normal adults. Int J Ophthalmol 2016; 9:617-24. [PMID: 27162739 DOI: 10.18240/ijo.2016.04.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 07/27/2015] [Indexed: 11/23/2022] Open
Abstract
AIM To examine the prevalence of dyslexia and Meares-Irlen syndrome (MIS) among female students and determine their level of visual stress in comparison with normal subjects. METHODS A random sample of 450 female medical students of King Saud University Riyadh (age range, 18-30y) responded to a wide range of questions designed to accomplish the aims of this study. The detailed questionnaire consisted of 54 questions with 12 questions enquiring on ocular history and demography of participants while 42 questions were on visual symptoms. Items were categorized into critical and non-critical questions (CQ and NCQ) and were rated on four point Likert scale. Based on the responses obtained, the subjects were grouped into normal (control), dyslexic with or without MIS (Group 1) and subjects with MIS only (Group 2). Responses were analysed as averages and mean scores were calculated and compared between groups using one way analysis of variance to evaluate total visual stress score (TVSS=NCQ+CQ), critical and non-critical visual stress scores. The relationship between categorical variables such as age, handedness and condition were assessed with Chi-square test. RESULTS The completion rate was 97.6% and majority of the respondents (92%) were normal readers, 2% dyslexic and 6% had MIS. They were age-matched. More than half of the participants had visited an eye care practitioner in the last 2y. About 13% were recommended eye exercises and one participant experienced pattern glare. Hand preference was not associated with any condition but Group 1 subjects (3/9, 33%) were significantly more likely to be diagnosed of lazy eye than Group 2 (2/27, 7%) and control (27/414, 7%) subjects. The mean±SD of TVSS responses were 63±14 and it was 44±9 for CQ and 19±5 for NCQ. Responses from all three variables were normally distributed but the CQ responses were on the average more positive (82%) in Group 2 and less positive (46%) in Group 1 than control. With NCQ, the responses were equally less positive in Group 1 and 2 than control. Group 2 subjects showed significantly higher TVSS (P=0.002), NCQ (P=0.006) and CQ (P=0.008) visual stress scores than control but no difference between Group 1 and control subjects, was observed for all scores (P>0.05, for all comparisons). CONCLUSION The prevalence of dyslexia and MIS among Saudi female students was 2% and 6%, respectively. Critical questions performed best for assessing visual stress symptoms in dyslexic and MIS subjects. Generally, students with MIS were more sensitive to visual stress than normal students but dyslexics were more likely to present with a lazy eye than MIS and normal readers.
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Affiliation(s)
- Mana A Alanazi
- Department of Optometry & Vision Science, King Saud University, Riyadh 11433, Saudi Arabia
| | - Saud A Alanazi
- Department of Optometry & Vision Science, King Saud University, Riyadh 11433, Saudi Arabia
| | - Uchechukwu L Osuagwu
- Ophthalmic and Visual Optics Laboratory Group, Institute of Health and Biomedical Innovation, Department of Optometry & Vision Sciences, Faculty of Health, Queensland University of Technology, Brisbane 4059, Queensland, Australia
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Schenkel LC, Rodenhiser DI, Ainsworth PJ, Paré G, Sadikovic B. DNA methylation analysis in constitutional disorders: Clinical implications of the epigenome. Crit Rev Clin Lab Sci 2016; 53:147-65. [PMID: 26758403 DOI: 10.3109/10408363.2015.1113496] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Genomic, chromosomal, and gene-specific changes in the DNA sequence underpin both phenotypic variations in populations as well as disease associations, and the application of genomic technologies for the identification of constitutional (inherited) or somatic (acquired) alterations in DNA sequence forms a cornerstone of clinical and molecular genetics. In addition to the disruption of primary DNA sequence, the modulation of DNA function by epigenetic phenomena, in particular by DNA methylation, has long been known to play a role in the regulation of gene expression and consequent pathogenesis. However, these epigenetic factors have been identified only in a handful of pediatric conditions, including imprinting disorders. Technological advances in the past decade that have revolutionized clinical genomics are now rapidly being applied to the emerging discipline of clinical epigenomics. Here, we present an overview of epigenetic mechanisms with a focus on DNA modifications, including the molecular mechanisms of DNA methylation and subtypes of DNA modifications, and we describe the classic and emerging genomic technologies that are being applied to this study. This review focuses primarily on constitutional epigenomic conditions associated with a spectrum of developmental and intellectual disabilities. Epigenomic disorders are discussed in the context of global genomic disorders, imprinting disorders, and single gene disorders. We include a section focused on integration of genetic and epigenetic mechanisms together with their effect on clinical phenotypes. Finally, we summarize emerging epigenomic technologies and their impact on diagnostic aspects of constitutional genetic and epigenetic disorders.
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Affiliation(s)
| | - David I Rodenhiser
- b Departments of Biochemistry , Oncology and Paediatrics, Western University , London , ON , Canada .,c London Regional Cancer Program, London Health Sciences Centre , London , ON , Canada .,e Children's Health Research Institute , London , ON , Canada
| | - Peter J Ainsworth
- a Departments of Pathology and Laboratory Medicine .,b Departments of Biochemistry , Oncology and Paediatrics, Western University , London , ON , Canada .,c London Regional Cancer Program, London Health Sciences Centre , London , ON , Canada .,d Molecular Genetics Laboratory, London Health Sciences Centre , London , ON , Canada .,e Children's Health Research Institute , London , ON , Canada
| | - Guillaume Paré
- f Department of Pathology and Molecular Medicine , and.,g Department of Clinical Epidemiology and Biostatistics , McMaster University , Hamilton , ON , Canada
| | - Bekim Sadikovic
- a Departments of Pathology and Laboratory Medicine .,c London Regional Cancer Program, London Health Sciences Centre , London , ON , Canada .,d Molecular Genetics Laboratory, London Health Sciences Centre , London , ON , Canada .,e Children's Health Research Institute , London , ON , Canada
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Einarsdottir E, Svensson I, Darki F, Peyrard-Janvid M, Lindvall JM, Ameur A, Jacobsson C, Klingberg T, Kere J, Matsson H. Mutation in CEP63 co-segregating with developmental dyslexia in a Swedish family. Hum Genet 2015; 134:1239-48. [PMID: 26400686 PMCID: PMC4628622 DOI: 10.1007/s00439-015-1602-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/15/2015] [Indexed: 01/17/2023]
Abstract
Developmental dyslexia is the most common learning disorder in children. Problems in reading and writing are likely due to a complex interaction of genetic and environmental factors, resulting in reduced power of studies of the genetic factors underlying developmental dyslexia. Our approach in the current study was to perform exome sequencing of affected and unaffected individuals within an extended pedigree with a familial form of developmental dyslexia. We identified a two-base mutation, causing a p.R229L amino acid substitution in the centrosomal protein 63 kDa (CEP63), co-segregating with developmental dyslexia in this pedigree. This mutation is novel, and predicted to be highly damaging for the function of the protein. 3D modelling suggested a distinct conformational change caused by the mutation. CEP63 is localised to the centrosome in eukaryotic cells and is required for maintaining normal centriole duplication and control of cell cycle progression. We found that a common polymorphism in the CEP63 gene had a significant association with brain white matter volume. The brain regions were partly overlapping with the previously reported region influenced by polymorphisms in the dyslexia susceptibility genes DYX1C1 and KIAA0319. We hypothesise that CEP63 is particularly important for brain development and might control the proliferation and migration of cells when those two events need to be highly coordinated.
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Affiliation(s)
- Elisabet Einarsdottir
- Department of Biosciences and Nutrition, and Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.
| | - Idor Svensson
- Department of Psychology, Linneaus University, Växjö, Sweden
| | - Fahimeh Darki
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Myriam Peyrard-Janvid
- Department of Biosciences and Nutrition, and Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Jessica M Lindvall
- Department of Biosciences and Nutrition, and Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.,Bioinformatics Infrastructure for Life Sciences (BILS), Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Stockholm, Sweden.,Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Adam Ameur
- Uppsala Genome Center, Uppsala University, Uppsala, Sweden
| | | | - Torkel Klingberg
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Juha Kere
- Department of Biosciences and Nutrition, and Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.,Science for Life Laboratory, Stockholm University, Stockholm, Sweden.,Molecular Neurology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Hans Matsson
- Department of Biosciences and Nutrition, and Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
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Abstract
Dyslexia is a specific impairment in reading that affects 1 in 10 people. Previous studies have failed to isolate a single cause of the disorder, but several candidate genes have been reported. We measured motion perception in two groups of dyslexics, with and without a deletion within the DCDC2 gene, a risk gene for dyslexia. We found impairment for motion particularly strong at high spatial frequencies in the population carrying the deletion. The data suggest that deficits in motion processing occur in a specific genotype, rather than the entire dyslexia population, contributing to the large variability in impairment of motion thresholds in dyslexia reported in the literature.
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50
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An assessment of gene-by-gene interactions as a tool to unfold missing heritability in dyslexia. Hum Genet 2015; 134:749-60. [DOI: 10.1007/s00439-015-1555-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/12/2015] [Indexed: 12/24/2022]
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