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Nandakumar R, Shi X, Gu H, Kim Y, Raskind WH, Peter B, Dinu V. Joint exome and metabolome analysis in individuals with dyslexia: Evidence for associated dysregulations of olfactory perception and autoimmune functions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.27.600448. [PMID: 39005457 PMCID: PMC11244894 DOI: 10.1101/2024.06.27.600448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Dyslexia is a learning disability that negatively affects reading, writing, and spelling development at the word level in 5%-9% of children. The phenotype is variable and complex, involving several potential cognitive and physical concomitants such as sensory dysregulation and immunodeficiencies. The biological pathogenesis is not well-understood. Toward a better understanding of the biological drivers of dyslexia, we conducted the first joint exome and metabolome investigation in a pilot sample of 30 participants with dyslexia and 13 controls. In this analysis, eight metabolites of interest emerged (pyridoxine, kynurenic acid, citraconic acid, phosphocreatine, hippuric acid, xylitol, 2-deoxyuridine, and acetylcysteine). A metabolite-metabolite interaction analysis identified Krebs cycle intermediates that may be implicated in the development of dyslexia. Gene ontology analysis based on exome variants resulted in several pathways of interest, including the sensory perception of smell (olfactory) and immune system-related responses. In the joint exome and metabolite analysis, the olfactory transduction pathway emerged as the primary pathway of interest. Although the olfactory transduction and Krebs cycle pathways have not previously been described in dyslexia literature, these pathways have been implicated in other neurodevelopmental disorders including autism spectrum disorder and obsessive-compulsive disorder, suggesting the possibility of these pathways playing a role in dyslexia as well. Immune system response pathways, on the other hand, have been implicated in both dyslexia and other neurodevelopmental disorders.
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Derbyshire E, Maes M. The Role of Choline in Neurodevelopmental Disorders-A Narrative Review Focusing on ASC, ADHD and Dyslexia. Nutrients 2023; 15:2876. [PMID: 37447203 DOI: 10.3390/nu15132876] [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: 06/02/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Neurodevelopmental disorders appear to be rising in prevalence, according to the recent Global Burden of Disease Study. This rise is likely to be multi-factorial, but the role of certain nutrients known to facilitate neurodevelopment should be considered. One possible contributing factor could be attributed to deficits in choline intake, particularly during key stages of neurodevelopment, which includes the first 1000 days of life and childhood. Choline, a key micronutrient, is crucial for optimal neurodevelopment and brain functioning of offspring. The present narrative review discusses the main research, describing the effect of choline in neurodevelopmental disorders, to better understand its role in the etiology and management of these disorders. In terms of findings, low choline intakes and reduced or altered choline status have been reported in relevant population subgroups: pregnancy (in utero), children with autism spectrum disorders, people with attention deficit hyperactivity disorder and those with dyslexia. In conclusion, an optimal choline provision may offer some neuronal protection in early life and help to mitigate some cognitive effects in later life attributed to neurodevelopmental conditions. Research indicates that choline may act as a modifiable risk factor for certain neurodevelopmental conditions. Ongoing research is needed to unravel the mechanisms and explanations.
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Affiliation(s)
| | - Michael Maes
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok 4002, Thailand
- Research Institute, Medical University of Plovdiv, 10330 Plovdiv, Bulgaria
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3
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Cecil KM, Brunst KJ, Horowitz-Kraus T. Greater reading gain following intervention is associated with low magnetic resonance spectroscopy derived concentrations in the anterior cingulate cortex in children with dyslexia. Brain Res 2021; 1759:147386. [PMID: 33631208 PMCID: PMC7980091 DOI: 10.1016/j.brainres.2021.147386] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND/OBJECTIVE The "neural noise" hypothesis suggests that individuals with dyslexia have high glutamate concentrations associated with their reading challenges. Different reading intervention programs have showed low GLX (a combined measure for glutamine and glutamate obtained with in vivo magnetic resonance spectroscopy) in association with reading improvement. Several studies demonstrated improved reading and increased activation in the anterior cingulate cortex following an-executive-function (EF)-based reading intervention. The goals of the current study are two-fold: 1) to determine if the effect of the EF-based reading program extends also to the metabolite concentrations and in particular, on the GLX concentrations in the anterior cingulate cortex; 2) to expand the neural noise hypothesis in dyslexia also to neural networks supporting additional parts of the reading networks, i.e. in specific regions related to executive function skills. METHODS Children with dyslexia and typical readers were trained on the EF-based reading program. Reading ability was assessed before and after training while spectroscopy data was obtained at the end of the program. The association between change in reading scores following intervention and GLX concentrations was examined. RESULTS Greater "gains" in word reading were associated with low GLX, Glu, Cr, and NAA concentrations for children with dyslexia compared to typical readers. CONCLUSIONS These results suggest that the improvement reported following the EF-based reading intervention program also involved a low GLX concentration, as well as additional metabolites previously associated with better reading ability (Glx, Cr, NAA) which may point at the decreased neural noise, especially in the anterior cingulate cortex, as a possible mechanism for the effect of this program.
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Affiliation(s)
- Kim M Cecil
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, United States; Imaging Research Center, Cincinnati Children's Hospital Medical Center, United States; Department of Radiology, University of Cincinnati College of Medicine, United States
| | - Kelly J Brunst
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, United States
| | - Tzipi Horowitz-Kraus
- Educational Neuroimaging Center, Faculty of Biomedical Engineering, Faculty of Education in Science and Technology, Technicon Israel Institution of Technology, Israel; Reading and Literacy Discovery Center, United States; Division of General and Community Pediatrics, Department of Pediatrics, University of Cincinnati College of Medicine, United States.
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4
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Rahul DR, Ponniah RJ. The Modularity of Dyslexia. Pediatr Neonatol 2021; 62:240-248. [PMID: 33775610 DOI: 10.1016/j.pedneo.2021.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/24/2020] [Accepted: 03/05/2021] [Indexed: 10/21/2022] Open
Abstract
There is a growing interest in understanding dyslexia and the mechanisms involved in reading difficulties. Inquiries into the morphological and physiological changes of the brain have contributed to our increased understanding of reading ability and dyslexia. Similarly, inquiries into brain chemistry and reading provide a neurometabolic framework of dyslexia in terms of poor reading and phonological measures. Also, studies of the genetic etiology of reading yield substantial evidence of genes and SNPs associated with dyslexia. However, little is known about the interface between these distinct areas of knowledge. Therefore, we offer an exhaustive perspective on dyslexia using the idea of modularity by assimilating the findings and implications from the brain morphological, neurophysiological, neurochemical, genetic, and educational insights into dyslexia. We contend that this endeavor will provide a beneficial foundation for aiming at the possibilities of a holistic intervention and informed solutions for reading difficulties.
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Affiliation(s)
- D R Rahul
- Department of Humanities and Social Sciences, National Institute of Technology, Tiruchirappalli, India
| | - R Joseph Ponniah
- Department of Humanities and Social Sciences, National Institute of Technology, Tiruchirappalli, India.
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Montani V, Chanoine V, Stoianov IP, Grainger J, Ziegler JC. Steady state visual evoked potentials in reading aloud: Effects of lexicality, frequency and orthographic familiarity. BRAIN AND LANGUAGE 2019; 192:1-14. [PMID: 30826643 DOI: 10.1016/j.bandl.2019.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/16/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
The present study explored the possibility to use Steady-State Visual Evoked Potentials (SSVEPs) as a tool to investigate the core mechanisms in visual word recognition. In particular, we investigated three benchmark effects of reading aloud: lexicality (words vs. pseudowords), frequency (high-frequency vs. low-frequency words), and orthographic familiarity ('familiar' versus 'unfamiliar' pseudowords). We found that words and pseudowords elicited robust SSVEPs. Words showed larger SSVEPs than pseudowords and high-frequency words showed larger SSVEPs than low-frequency words. SSVEPs were not sensitive to orthographic familiarity. We further localized the neural generators of the SSVEP effects. The lexicality effect was located in areas associated with early level of visual processing, i.e. in the right occipital lobe and in the right precuneus. Pseudowords produced more activation than words in left sensorimotor areas, rolandic operculum, insula, supramarginal gyrus and in the right temporal gyrus. These areas are devoted to speech processing and/or spelling-to-sound conversion. The frequency effect involved the left temporal pole and orbitofrontal cortex, areas previously implicated in semantic processing and stimulus-response associations respectively, and the right postcentral and parietal inferior gyri, possibly indicating the involvement of the right attentional network.
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Affiliation(s)
- Veronica Montani
- Aix-Marseille University and CNRS, Brain and Language Research Institute, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France.
| | - Valerie Chanoine
- Aix-Marseille University, Institute of Language, Communication and the Brain, Brain and Language Research Institute, 13100 Aix-en-Provence, France
| | - Ivilin Peev Stoianov
- Aix-Marseille University and CNRS, LPC, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France; Institute of Cognitive Sciences and Technologies, CNR, Via Martiri della Libertà 2, 35137 Padova, Italy
| | - Jonathan Grainger
- Aix-Marseille University and CNRS, LPC, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France
| | - Johannes C Ziegler
- Aix-Marseille University and CNRS, LPC, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France
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Kossowski B, Chyl K, Kacprzak A, Bogorodzki P, Jednoróg K. Dyslexia and age related effects in the neurometabolites concentration in the visual and temporo-parietal cortex. Sci Rep 2019; 9:5096. [PMID: 30911032 PMCID: PMC6434036 DOI: 10.1038/s41598-019-41473-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 02/28/2019] [Indexed: 01/18/2023] Open
Abstract
Several etiological theories, in particular neuronal noise and impaired auditory sampling, predicted neurotransmission deficits in dyslexia. Neurometabolites also affect white matter microstructure, where abnormalities were previously reported in dyslexia. However findings from only few magnetic resonance spectroscopy studies using diverse age groups, different brain regions, data processing and reference scaling are inconsistent. We used MEGA-PRESS single-voxel spectroscopy in two ROIs: left temporo-parietal and occipital cortex in 36 adults and 52 children, where half in each group had dyslexia. Dyslexics, on average, had significantly lower total N-acetylaspartate (tNAA) than controls in the occipital cortex. Adults compared to children were characterized by higher choline and creatine in both areas, higher tNAA in left temporo-parietal and lower glutamate in the visual cortex, reflecting maturational changes in cortical microstructure and metabolism. Although the current findings do not support the proposed etiological theories of dyslexia, they show, for the first time, that tNAA, considered to be a neurochemical correlate of white matter integrity, is deficient in the visual cortex in both children and adults with dyslexia. They also point that several neurotransmitters, including ones previously used as reference, change with age.
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Affiliation(s)
- Bartosz Kossowski
- Faculty of Electronics and Information Technology Warsaw University of Technology, Nowowiejska 15/19, 00-665, Warsaw, Poland.
- Laboratory of Brain Imaging, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland.
| | - Katarzyna Chyl
- Laboratory of Language Neurobiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland
| | - Agnieszka Kacprzak
- Laboratory of Language Neurobiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland
- Faculty of Psychology, University of Warsaw, Stawki 5/7, 00-183, Warsaw, Poland
| | - Piotr Bogorodzki
- Faculty of Electronics and Information Technology Warsaw University of Technology, Nowowiejska 15/19, 00-665, Warsaw, Poland
| | - Katarzyna Jednoróg
- Laboratory of Language Neurobiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland.
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Borchers LR, Bruckert L, Dodson CK, Travis KE, Marchman VA, Ben-Shachar M, Feldman HM. Microstructural properties of white matter pathways in relation to subsequent reading abilities in children: a longitudinal analysis. Brain Struct Funct 2019; 224:891-905. [PMID: 30539288 PMCID: PMC6420849 DOI: 10.1007/s00429-018-1813-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 12/04/2018] [Indexed: 01/18/2023]
Abstract
Microstructural properties of white matter pathways are associated with concurrent reading abilities in children. In this longitudinal study, we asked whether properties of white matter pathways at the onset of learning to read would be associated with reading abilities at older ages. Children (N = 37) with a wide range of reading abilities completed standardized measures of language and phonological awareness and diffusion MRI at age 6 years. Mean tract-fractional anisotropy (FA) was extracted from reading-related pathways. At age 8, the same children were re-assessed using a standardized reading measure. Using linear regressions, we examined the contribution of tract-FA at age 6 to reading outcome at age 8, beyond known demographic and pre-literacy predictors of reading. Tract-FA of the left arcuate, left and right superior longitudinal fasciculus (SLF), and left inferior cerebellar peduncle (ICP) made unique contributions to reading outcome after consideration of sex and family history of reading delays. Tract-FA of the left and right SLF and left ICP made unique contributions to reading outcome after the addition of pre-literacy skills. Thus, cerebellar and bilateral cortical pathways represented a network associated with subsequent reading abilities. Early white matter properties may be associated with other neuropsychological functions that predict reading or may influence reading development, independent of reading-related abilities. Tract FA at early stages of learning to read may serve as a biomarker of later reading abilities.
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Affiliation(s)
- Lauren R Borchers
- Division of Developmental-Behavioral Pediatrics, Stanford University School of Medicine, Medical School Office Building, 1265 Welch Rd, Mail Code 5415, Stanford, 94305, CA, USA
| | - Lisa Bruckert
- Division of Developmental-Behavioral Pediatrics, Stanford University School of Medicine, Medical School Office Building, 1265 Welch Rd, Mail Code 5415, Stanford, 94305, CA, USA
| | - Cory K Dodson
- Division of Developmental-Behavioral Pediatrics, Stanford University School of Medicine, Medical School Office Building, 1265 Welch Rd, Mail Code 5415, Stanford, 94305, CA, USA
| | - Katherine E Travis
- Division of Developmental-Behavioral Pediatrics, Stanford University School of Medicine, Medical School Office Building, 1265 Welch Rd, Mail Code 5415, Stanford, 94305, CA, USA
| | | | - Michal Ben-Shachar
- The Gonda Multidisciplinary Brain Research Center, Bar Ilan University, 5290002, Ramat Gan, Israel
- Department of English Literature and Linguistics, Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Heidi M Feldman
- Division of Developmental-Behavioral Pediatrics, Stanford University School of Medicine, Medical School Office Building, 1265 Welch Rd, Mail Code 5415, Stanford, 94305, CA, USA.
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8
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Del Tufo SN, Frost SJ, Hoeft F, Cutting LE, Molfese PJ, Mason GF, Rothman DL, Fulbright RK, Pugh KR. Neurochemistry Predicts Convergence of Written and Spoken Language: A Proton Magnetic Resonance Spectroscopy Study of Cross-Modal Language Integration. Front Psychol 2018; 9:1507. [PMID: 30233445 PMCID: PMC6131664 DOI: 10.3389/fpsyg.2018.01507] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 07/30/2018] [Indexed: 12/26/2022] Open
Abstract
Recent studies have provided evidence of associations between neurochemistry and reading (dis)ability (Pugh et al., 2014). Based on a long history of studies indicating that fluent reading entails the automatic convergence of the written and spoken forms of language and our recently proposed Neural Noise Hypothesis (Hancock et al., 2017), we hypothesized that individual differences in cross-modal integration would mediate, at least partially, the relationship between neurochemical concentrations and reading. Cross-modal integration was measured in 231 children using a two-alternative forced choice cross-modal matching task with three language conditions (letters, words, and pseudowords) and two levels of difficulty within each language condition. Neurometabolite concentrations of Choline (Cho), Glutamate (Glu), gamma-Aminobutyric (GABA), and N- acetyl-aspartate (NAA) were then measured in a subset of this sample (n = 70) with Magnetic Resonance Spectroscopy (MRS). A structural equation mediation model revealed that the effect of cross-modal word matching mediated the relationship between increased Glu (which has been proposed to be an index of neural noise) and poorer reading ability. In addition, the effect of cross-modal word matching fully mediated a relationship between increased Cho and poorer reading ability. Multilevel mixed effects models confirmed that lower Cho predicted faster cross-modal matching reaction time, specifically in the hard word condition. These Cho findings are consistent with previous work in both adults and children showing a negative association between Cho and reading ability. We also found two novel neurochemical relationships. Specifically, lower GABA and higher NAA predicted faster cross-modal matching reaction times. We interpret these results within a biochemical framework in which the ability of neurochemistry to predict reading ability may at least partially be explained by cross-modal integration.
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Affiliation(s)
- Stephanie N Del Tufo
- Department of Special Education, Peabody College, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN, United States.,Haskins Laboratories, New Haven, CT, United States
| | | | - Fumiko Hoeft
- Haskins Laboratories, New Haven, CT, United States.,Department of Psychiatry, University of California, San Francisco, San Francisco, CA, United States
| | - Laurie E Cutting
- Department of Special Education, Peabody College, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN, United States.,Haskins Laboratories, New Haven, CT, United States.,Peabody College of Education and Human Development, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN, United States
| | - Peter J Molfese
- Haskins Laboratories, New Haven, CT, United States.,Section on Functional Imaging Methods, Laboratory of Brain and Cognition, Department of Health and Human Services, National Institutes of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Graeme F Mason
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States.,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Douglas L Rothman
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States.,Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT, United States
| | - Robert K Fulbright
- Haskins Laboratories, New Haven, CT, United States.,Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States
| | - Kenneth R Pugh
- Haskins Laboratories, New Haven, CT, United States.,Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States.,Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
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Ramus F, Altarelli I, Jednoróg K, Zhao J, Scotto di Covella L. Neuroanatomy of developmental dyslexia: Pitfalls and promise. Neurosci Biobehav Rev 2017; 84:434-452. [PMID: 28797557 DOI: 10.1016/j.neubiorev.2017.08.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 07/28/2017] [Accepted: 08/02/2017] [Indexed: 01/18/2023]
Abstract
Investigations into the neuroanatomical bases of developmental dyslexia have now spanned more than 40 years, starting with the post-mortem examination of a few individual brains in the 60s and 70s, and exploding in the 90s with the widespread use of MRI. The time is now ripe to reappraise the considerable amount of data gathered with MRI using different types of sequences (T1, diffusion, spectroscopy) and analysed using different methods (manual, voxel-based or surface-based morphometry, fractional anisotropy and tractography, multivariate analyses…). While selective reviews of mostly small-scale studies seem to provide a coherent view of the brain disruptions that are typical of dyslexia, involving left perisylvian and occipito-temporal regions, we argue that this view may be deceptive and that meta-analyses and large-scale studies rather highlight many inconsistencies and limitations. We discuss problems inherent to small sample size as well as methodological difficulties that still undermine the discovery of reliable neuroanatomical bases of dyslexia, and we outline some recommendations to further improve this research area.
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Affiliation(s)
- Franck Ramus
- Laboratoire de sciences cognitives et psycholinguistique (CNRS, ENS, EHESS, PSL Research University), Ecole Normale Supérieure, 29 rue d'Ulm, 75005 Paris, France.
| | - Irene Altarelli
- Brain and Learning Lab, Campus Biotech, University of Geneva, 9 Chemin des Mines, 1205 Geneva, Switzerland
| | - Katarzyna Jednoróg
- Laboratory of Psychophysiology, Department of Neurophysiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St, 02-093 Warsaw, Poland
| | - Jingjing Zhao
- School of Psychology, Shaanxi Normal University and Key Laboratory for Behavior and Cognitive Neuroscience of Shaanxi Province, Xi'an, Shaanxi, 710062, China
| | - Lou Scotto di Covella
- Laboratoire de sciences cognitives et psycholinguistique (CNRS, ENS, EHESS, PSL Research University), Ecole Normale Supérieure, 29 rue d'Ulm, 75005 Paris, France
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Fernandez VG, Juranek J, Romanowska-Pawliczek A, Stuebing K, Williams VJ, Fletcher JM. White matter integrity of cerebellar-cortical tracts in reading impaired children: A probabilistic tractography study. BRAIN AND LANGUAGE 2016; 161:45-56. [PMID: 26307492 PMCID: PMC4803624 DOI: 10.1016/j.bandl.2015.07.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 07/01/2015] [Accepted: 07/10/2015] [Indexed: 06/04/2023]
Abstract
Little is known about the white matter integrity of cerebellar-cortical pathways in individuals with dyslexia. Building on previous findings of decreased volume in the anterior lobe of the cerebellum, we utilized novel cerebellar segmentation procedures and probabilistic tractography to examine tracts that connect the anterior lobe of the cerebellum and cortical regions typically associated with reading: the temporoparietal (TP), occipitotemporal (OT), and inferior frontal (IF) regions. The sample included 29 reading impaired children and 27 typical readers. We found greater fractional anisotropy (FA) for the poor readers in tracts connecting the cerebellum with TP and IF regions relative to typical readers. In the OT region, FA was greater for the older poor readers, but smaller for the younger ones. This study provides evidence for discrete, regionally-bound functions of the cerebellum and suggests that projections from the anterior cerebellum appear to have a regulatory effect on cortical pathways important for reading.
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Affiliation(s)
- Vindia G Fernandez
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
| | - Jenifer Juranek
- University of Texas Health Science Center, 6655 Travis, Houston, TX 77030-1312, United States.
| | | | - Karla Stuebing
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
| | - Victoria J Williams
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
| | - Jack M Fletcher
- University of Houston, 4811 Calhoun Rd., 3rd Floor, Houston, TX 77204-6022, United States.
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Ozernov-Palchik O, Yu X, Wang Y, Gaab N. Lessons to be learned: how a comprehensive neurobiological framework of atypical reading development can inform educational practice. Curr Opin Behav Sci 2016; 10:45-58. [PMID: 27766284 DOI: 10.1016/j.cobeha.2016.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Dyslexia is a heritable reading disorder with an estimated prevalence of 5-17%. A multiple deficit model has been proposed that illustrates dyslexia as an outcome of multiple risks and protective factors interacting at the genetic, neural, cognitive, and environmental levels. Here we review the evidence on each of these levels and discuss possible underlying mechanisms and their reciprocal interactions along a developmental timeline. Current and potential implications of neuroscientific findings for contemporary challenges in the field of dyslexia, as well as for reading development and education in general, are then discussed.
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Affiliation(s)
- Ola Ozernov-Palchik
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Center for Reading and Language Research, Tufts University, Medford, MA 02155, United States
| | - Xi Yu
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Harvard Medical School, Boston, MA 02115, United States
| | - Yingying Wang
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Harvard Medical School, Boston, MA 02115, United States
| | - Nadine Gaab
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Department of Medicine, Children's Hospital Boston, MA 02115, United States; Harvard Medical School, Boston, MA 02115, United States; Harvard Graduate School of Education, Cambridge, MA 02138, United States
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12
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Travis KE, Leitner Y, Feldman HM, Ben-Shachar M. Cerebellar white matter pathways are associated with reading skills in children and adolescents. Hum Brain Mapp 2014; 36:1536-53. [PMID: 25504986 DOI: 10.1002/hbm.22721] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 11/10/2014] [Accepted: 12/04/2014] [Indexed: 01/18/2023] Open
Abstract
Reading is a critical life skill in the modern world. The neural basis of reading incorporates a distributed network of cortical areas and their white matter connections. The cerebellum has also been implicated in reading and reading disabilities. However, little is known about the contribution of cerebellar white matter pathways to major component skills of reading. We used diffusion magnetic resonance imaging (dMRI) with tractography to identify the cerebellar peduncles in a group of 9- to 17-year-old children and adolescents born full term (FT, n = 19) or preterm (PT, n = 26). In this cohort, no significant differences were found between fractional anisotropy (FA) measures of the peduncles in the PT and FT groups. FA of the cerebellar peduncles correlated significantly with measures of decoding and reading comprehension in the combined sample of FT and PT subjects. Correlations were negative in the superior and inferior cerebellar peduncles and positive in the middle cerebellar peduncle. Additional analyses revealed that FT and PT groups demonstrated similar patterns of reading associations within the left superior cerebellar peduncle, middle cerebellar peduncle, and left inferior cerebellar peduncle. Partial correlation analyses showed that distinct sub-skills of reading were associated with FA in segments of different cerebellar peduncles. Overall, the present findings are the first to document associations of microstructure of the cerebellar peduncles and the component skills of reading.
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Affiliation(s)
- Katherine E Travis
- Division of Neonatal and Developmental Medicine, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California
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de Freitas PB, Pedão ST, Barela JA. Visuomotor processing and hand force coordination in dyslexic children during a visually guided manipulation task. RESEARCH IN DEVELOPMENTAL DISABILITIES 2014; 35:2352-2358. [PMID: 24960554 DOI: 10.1016/j.ridd.2014.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
Developmental Dyslexia negatively affects children's reading and writing ability and, in most cases, performance in sensorimotor tasks. These deficits have been associated with structural and functional alterations in the cerebellum and the posterior parietal cortex (PPC). Both neural structures are active during visually guided force control and in the coordination of load force (LF) and grip force (GF) during manipulation tasks. Surprisingly, both phenomena have not been investigated in dyslexic children. Therefore, the aim of this study was to compare dyslexic and non-dyslexic children regarding their visuomotor processing ability and GF-LF coordination during a static manipulation task. Thirteen dyslexic (8-14 YO) and 13 age- and sex-matched non-dyslexic (control) children participated in the study. They were asked to grasp a fixed instrumented handle using the tip of all digits and pull the handle upward exerting isometric force to match a ramp-and-hold force profile displayed in a computer monitor. Task performance (i.e., visuomotor coordination) was assessed by RMSE calculated in both ramp and hold phases. GF-LF coordination was assessed by the ratio between GF and LF (GF/LF) calculated at both phases and the maximum value of a cross-correlation function (rmax) and its respective time lag calculated at ramp phase. The results revealed that the RMSE at both phases was larger in dyslexic than in control children. However, we found that GF/LF, rmax, and time lags were similar between groups. Those findings indicate that dyslexic children have a mild deficit in visuomotor processing but preserved GF-LF coordination. Altogether, these findings suggested that dyslexic children could present mild structural and functional alterations in specific PPC or cerebellum areas that are directly related to visuomotor processing.
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Affiliation(s)
- Paulo B de Freitas
- Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil.
| | - Sabrina T Pedão
- Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil
| | - Jose A Barela
- Graduate Program in Human Movement Science, Institute of Physical Activity and Sport Sciences, Cruzeiro do Sul University, São Paulo, SP, Brazil; Department of Physical Education, Institute of Biosciences, São Paulo State University, Rio Claro, SP, Brazil
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Volumetric analysis of regional variability in the cerebellum of children with dyslexia. THE CEREBELLUM 2014; 12:906-15. [PMID: 23828023 DOI: 10.1007/s12311-013-0504-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cerebellar deficits and subsequent impairment in procedural learning may contribute to both motor difficulties and reading impairment in dyslexia. We used quantitative magnetic resonance imaging to investigate the role of regional variation in cerebellar anatomy in children with single-word decoding impairments (N = 23), children with impairment in fluency alone (N = 8), and typically developing children (N = 16). Children with decoding impairments (dyslexia) demonstrated no statistically significant differences in overall grey and white matter volumes or cerebellar asymmetry; however, reduced volume in the anterior lobe of the cerebellum relative to typically developing children was observed. These results implicate cerebellar involvement in dyslexia and establish an important foundation for future research on the connectivity of the cerebellum and cortical regions typically associated with reading impairment.
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Ashkenazi S, Black JM, Abrams DA, Hoeft F, Menon V. Neurobiological underpinnings of math and reading learning disabilities. JOURNAL OF LEARNING DISABILITIES 2013; 46:549-69. [PMID: 23572008 PMCID: PMC3795983 DOI: 10.1177/0022219413483174] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The primary goal of this review is to highlight current research and theories describing the neurobiological basis of math (MD), reading (RD), and comorbid math and reading disability (MD+RD). We first describe the unique brain and cognitive processes involved in acquisition of math and reading skills, emphasizing similarities and differences in each domain. Next we review functional imaging studies of MD and RD in children, integrating relevant theories from experimental psychology and cognitive neuroscience to characterize the functional neuroanatomy of cognitive dysfunction in MD and RD. We then review recent research on the anatomical correlates of MD and RD. Converging evidence from morphometry and tractography studies are presented to highlight distinct patterns of white matter pathways which are disrupted in MD and RD. Finally, we examine how the intersection of MD and RD provides a unique opportunity to clarify the unique and shared brain systems which adversely impact learning and skill acquisition in MD and RD, and point out important areas for future work on comorbid learning disabilities.
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Affiliation(s)
| | | | | | - Fumiko Hoeft
- University of California, San Francisco, San Francisco, CA, USA
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Danelli L, Berlingeri M, Bottini G, Ferri F, Vacchi L, Sberna M, Paulesu E. Neural intersections of the phonological, visual magnocellular and motor/cerebellar systems in normal readers: implications for imaging studies on dyslexia. Hum Brain Mapp 2013; 34:2669-87. [PMID: 22736513 PMCID: PMC6870382 DOI: 10.1002/hbm.22098] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 03/14/2012] [Accepted: 03/15/2012] [Indexed: 01/27/2023] Open
Abstract
We used fMRI to explore the extent of the anatomical overlap of three neural systems that the literature on developmental dyslexia associates with reading: the auditory phonological, the visual magnocellular, and the motor/cerebellar systems. Twenty-eight normal subjects performed four tasks during fMRI scans: word and pseudoword reading, auditory rhyming for letter names, visual motion perception, and a motor sequence learning task. We found that the left occipitotemporal cortex (OTC), which previous studies reported to be dysfunctional in dyslexia, can be fractionated into different functional areas: an anterior and lateral area that was activated by both reading and auditory rhyming tasks; a posterior area that was commonly activated by both the reading and the motion perception task and a medial/intermediate area, including the so-called Visual Word Form Area, which was specifically activated by the reading task. These results show that the left OTC is an area of segregated convergence of different functional systems. We compared our results with the hypoactivation pattern reported for reading in a previous cross-cultural PET study on 36 dyslexic subjects from three countries. The region of decreased activation in dyslexia overlapped with regions that are specific for reading and those activated during both the auditory rhyming task and the single word and pseudoword reading task described in the present fMRI study. No overlap was found with the activation patterns for the visual motion perception task or for the motor sequence learning task. These observations challenge current theories of dyslexia.
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Affiliation(s)
- Laura Danelli
- Psychology Department, University of Milano-Bicocca, Milan, Italy
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17
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Is learning by observation impaired in children with dyslexia? Neuropsychologia 2011; 49:1996-2003. [DOI: 10.1016/j.neuropsychologia.2011.03.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 11/22/2010] [Accepted: 03/22/2011] [Indexed: 11/22/2022]
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18
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Integration of proprioceptive signals and attentional capacity during postural control are impaired but subject to improvement in dyslexic children. Exp Brain Res 2011; 209:599-608. [PMID: 21359661 DOI: 10.1007/s00221-011-2593-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 02/04/2011] [Indexed: 12/19/2022]
Abstract
Children with developmental dyslexia suffer from delayed reading capabilities and may also exhibit attentional and sensori-motor deficits. The objective of this study was twofold. First, we aimed at investigating whether integration of proprioceptive signals in balance control was more impaired in dyslexic children when the attentional demand was varied. Secondly, we checked whether this effect was reduced significantly by using a specific treatment to improve eye control deficits and certain postural signs that are often linked to dyslexia (Quercia et al. in J Fr Ophtalmol 28:713-723, 2005, J Fr Ophtalmol 30:380-89, 2007). Thirty dyslexic and 51 treated dyslexic children (> 3 months of treatment) were compared with 42 non-dyslexic children in several conditions (mean age: 136.2 ± 23.6, 132.2 ± 18.7 and 140.2 ± 25 months, respectively). Co-vibration of ankle muscles was effected in order to alter proprioceptive information originating from the ankle. In two vibration conditions, ankle muscles were either not vibrated or vibrated at 85 Hz without illusion of any movement. These two vibration conditions were combined with two attentional conditions. In the first such condition, children maintained balance while merely fixing their gaze on a point in front of them. In the second condition, they had to look for smaller or larger stars in a panel showing forty of each kind. Balance was assessed by means of a force plate. Results indicated that the mean velocity (i.e. the total length) of the center of pressure (CoP) displacement in the 85-Hz vibration condition increased significantly more (compared with no vibration) in the dyslexic and the treated dyslexic groups than in the control group, irrespective of the attention task. Interestingly, in the condition without vibration, the attentional performance of treated children was similar to that of the control group, whereas the attentional performance of the untreated dyslexic children was significantly impaired. Altogether, these results suggest that integration of proprioceptive signals in balance control and attentional capacity are impaired in dyslexic children. However, attention capacity during the control of stance could be improved significantly.
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Menghini D, Finzi A, Carlesimo GA, Vicari S. Working Memory Impairment in Children With Developmental Dyslexia: Is it Just a Phonological Deficity? Dev Neuropsychol 2011; 36:199-213. [DOI: 10.1080/87565641.2010.549868] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Krafnick AJ, Flowers DL, Napoliello EM, Eden GF. Gray matter volume changes following reading intervention in dyslexic children. Neuroimage 2010; 57:733-41. [PMID: 21029785 DOI: 10.1016/j.neuroimage.2010.10.062] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 10/18/2010] [Accepted: 10/20/2010] [Indexed: 01/20/2023] Open
Abstract
Studies in children and adults with the reading disability developmental dyslexia have shown behavioral improvements after reading intervention. In another line of work, it has been shown that intensive training in a variety of cognitive and sensorimotor skills can result in changes in gray matter volume (GMV). This study examined changes in GMV following intensive reading intervention in children with dyslexia using voxel-based morphometry (VBM). Eleven dyslexic children underwent an eight week training focused on mental imagery, articulation and tracing of letters, groups of letters and words, which resulted in significant gains in reading skills. This was followed by an eight week null period (control) where no intervention was administered and no further significant gains in reading were observed. Structural scans were obtained before the intervention, after the intervention and after the null period. GMV increases between the first two time points were found in the left anterior fusiform gyrus/hippocampus, left precuneus, right hippocampus and right anterior cerebellum. However these areas did not change between time points two and three (control period), suggesting that the changes were specific to the intervention period. These results demonstrate for the first time that (1) training-induced changes in GMV can be observed in a pediatric sample and (2) reading improvements induced by intervention are accompanied by GMV changes.
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Affiliation(s)
- Anthony J Krafnick
- Center for the Study of Learning, Georgetown University Medical Center, 4000 Reservoir Road, Building D Suite 150, Washington, DC 20057, USA.
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Barth AE, Denton CA, Stuebing KK, Fletcher JM, Cirino PT, Francis DJ, Vaughn S. A test of the cerebellar hypothesis of dyslexia in adequate and inadequate responders to reading intervention. J Int Neuropsychol Soc 2010; 16:526-36. [PMID: 20298639 PMCID: PMC3891301 DOI: 10.1017/s1355617710000135] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The cerebellar hypothesis of dyslexia posits that cerebellar deficits are associated with reading disabilities and may explain why some individuals with reading disabilities fail to respond to reading interventions. We tested these hypotheses in a sample of children who participated in a grade 1 reading intervention study (n = 174) and a group of typically achieving children (n = 62). At posttest, children were classified as adequately responding to the intervention (n = 82), inadequately responding with decoding and fluency deficits (n = 36), or inadequately responding with only fluency deficits (n = 56). Based on the Bead Threading and Postural Stability subtests from the Dyslexia Screening Test-Junior, we found little evidence that assessments of cerebellar functions were associated with academic performance or responder status. In addition, we did not find evidence supporting the hypothesis that cerebellar deficits are more prominent for poor readers with "specific" reading disabilities (i.e., with discrepancies relative to IQ) than for poor readers with reading scores consistent with IQ. In contrast, measures of phonological awareness, rapid naming, and vocabulary were strongly associated with responder status and academic outcomes. These results add to accumulating evidence that fails to associate cerebellar functions with reading difficulties.
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Affiliation(s)
- Amy E Barth
- Department of Psychology, Texas Institute of Measurement, Evaluation, and Statistics, Texas Center for Learning Disabilities, University of Houston, Houston, Texas 77204-5053, USA.
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Sun YF, Lee JS, Kirby R. Brain imaging findings in dyslexia. Pediatr Neonatol 2010; 51:89-96. [PMID: 20417459 DOI: 10.1016/s1875-9572(10)60017-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 07/07/2009] [Accepted: 07/28/2009] [Indexed: 01/18/2023] Open
Abstract
Dyslexia is a brain-based disorder that has been intensively studied in the Western world for more than a century because of its social burden. However, affected individuals in Chinese communities are neither recognized nor formally diagnosed. Previous studies have concentrated on the disadvantages of reading deficits, and few have addressed non-linguistic skills, which are included in the symptoms. In addition, certain dyslexics possess visual spatial talents that have usually been ignored. In this review, we discuss the available information regarding brain imaging studies of dyslexia based on studies in Caucasian subjects. Gray matter deficits have been demonstrated in dyslexics using structural magnetic resonance imaging. Reduced neural activities in the left temporal and left parietal cortices, and diffuse widespread activation patterns in the cerebellum could be detected using functional magnetic resonance imaging. Changes in lactate levels, N-acetylaspartate/choline-containing compounds and N-acetylaspartate/creatine ratios, and phosphomonoester peak area were detected in magnetic resonance spectroscopy studies. Lower fractional anisotropy values in bilateral white matter tracts have been demonstrated by diffusion tensor imaging. Abnormal Broca's area activation was found using positron emission tomography imaging. Increased activities in the right frontal and temporal brain regions were detected using electroencephalography. Reduced hemispheric asymmetry and increased left inferior frontal activation were reported following magnetoencephalography. Although these imaging modalities are not currently diagnostic or prognostic, they are able to provide information on the causes of dyslexia beyond what was previously provided by behavioral or cognition studies.
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Affiliation(s)
- Ying-Fang Sun
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.
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