1
|
Pasqualotto A, Mazzoni N, Benso F, Chiorri C. Reading Skill Profiles in School-Aged Italian-Speaking Children: A Latent Profile Analysis Investigation into the Interplay of Decoding, Comprehension and Attentional Control. Brain Sci 2024; 14:390. [PMID: 38672039 PMCID: PMC11048682 DOI: 10.3390/brainsci14040390] [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: 03/18/2024] [Revised: 04/10/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Our study examined the complex relationships among reading performance (decoding, comprehension) and language, visuo-spatial, and attentional control abilities in 115 Italian-speaking children. Latent profile analysis was used to identify distinct clusters of participants showcasing quantitative differences in decoding skills, including word, pseudo-word, text reading speed and accuracy. Then, we used this classification to investigate group differences in a variety of linguistic, working memory, and visuo-spatial tasks, as well as in reading comprehension skills, by means of multivariate and univariate tests. Our results reveal significant links between reading proficiency and several key factors: language skills, visuo-spatial abilities, and attentional control. These findings illuminate the nuanced impact of domain-general processes that govern a series of linguistic and visuo-perceptive subcomponents during reading tasks. Additionally, using dominance analysis, predictors of written text comprehension were identified. Our findings suggest that effective reading comprehension relies on a synergistic interplay of adequate reading speed, attentional control, working memory, and verbal fluency, accounting for 23% of the explained variance. This study highlights the multifaceted nature of reading proficiency and suggests that a broader perspective is necessary to fully understand reading development and support its improvement.
Collapse
Affiliation(s)
- Angela Pasqualotto
- Department of Psychology and Cognitive Science, University of Trento, 38068 Rovereto, TN, Italy; (N.M.); (F.B.)
- Department of Education and Learning, University of Applied Sciences and Arts of Southern Switzerland, 6600 Locarno, Switzerland
- Faculty of Psychology and Educational Sciences, University of Geneva, 1205 Geneva, Switzerland
| | - Noemi Mazzoni
- Department of Psychology and Cognitive Science, University of Trento, 38068 Rovereto, TN, Italy; (N.M.); (F.B.)
| | - Francesco Benso
- Department of Psychology and Cognitive Science, University of Trento, 38068 Rovereto, TN, Italy; (N.M.); (F.B.)
| | - Carlo Chiorri
- Department of Educational Sciences, University of Genoa, 16126 Genoa, GE, Italy
| |
Collapse
|
2
|
Packheiser J, Papadatou-Pastou M, Koufaki A, Paracchini S, Stein CC, Schmitz J, Ocklenburg S. Elevated levels of mixed-hand preference in dyslexia: Meta-analyses of 68 studies. Neurosci Biobehav Rev 2023; 154:105420. [PMID: 37783301 DOI: 10.1016/j.neubiorev.2023.105420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/04/2023]
Abstract
Since almost a hundred years, psychologists have investigated the link between hand preference and dyslexia. We present a meta-analysis to determine whether there is indeed an increase in atypical hand preference in dyslexia. We included studies used in two previous meta-analyses (Bishop, 1990; Eglinton & Annett, 1994) as well as studies identified through PubMed MEDLINE, PsycInfo, Google Scholar, and Web of Science up to August 2022. K = 68 studies (n = 4660 individuals with dyslexia; n = 40845 controls) were entered into three random effects meta-analyses using the odds ratio as the effect size (non-right-handers; left-handers; mixed-handers vs. total). Evidence of elevated levels of atypical hand preference in dyslexia emerged that were especially pronounced for mixed-hand preference (OR = 1.57), although this category was underdefined. Differences in (direction or degree) of hand skill or degree of hand preference could not be assessed as no pertinent studies were located. Our findings allow for robust conclusions only for a relationship of mixed-hand preference with dyslexia.
Collapse
Affiliation(s)
- Julian Packheiser
- Social Brain Lab, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Marietta Papadatou-Pastou
- School of Education, National and Kapodistrian University of Athens, Athens, Greece; BioMedical Research Foundation of the Academy of Athens, Athens, Greece.
| | - Angeliki Koufaki
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Clara C Stein
- Division of Forensic Psychiatry, Department of Psychiatry, Psychotherapy, and Preventive Medicine, LWL-University Hospital Bochum, Bochum, Germany
| | - Judith Schmitz
- Biological Personality Psychology, Georg-August-University Goettingen, Goettingen, Germany
| | - Sebastian Ocklenburg
- Department of Psychology, Medical School Hamburg, Hamburg, Germany; ICAN Institute for Cognitive and Affective Neuroscience, Medical School Hamburg, Hamburg, Germany; Institute of Cognitive Neuroscience, Biopsychology, Department of Psychology, Ruhr-University Bochum, Bochum, Germany
| |
Collapse
|
3
|
Benso F, Moretti S, Bellazzini V, Benso E, Ardu E, Gazzellini S. Principles of Integrated Cognitive Training for Executive Attention: Application to an Instrumental Skill. Front Psychol 2021; 12:647749. [PMID: 34239477 PMCID: PMC8258243 DOI: 10.3389/fpsyg.2021.647749] [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] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 05/17/2021] [Indexed: 11/16/2022] Open
Abstract
One effective cognitive treatment is the rehabilitation of working memory (WM) using an integrated approach that targets the “executive attention” system. Recent neuroscientific literature has revealed that treatment efficacy depends on the presence of various features, such as adaptivity, empathy, customization, avoidance of automatism and stereotypies, and alertness activation. Over the last two decades, an Integrated Cognitive Training (ICT) protocol has been proposed and developed; ICT takes the above-mentioned features and existing literature into account, and has been used to promote the development of reading skills. ICT has been employed in several clinical settings and involves stimulation of a specific deteriorated system (e.g., reading) and the improvement of executive attention components, thus also increasing working memory capacity. In this context, we present two experiments. In Experiment 1, participants diagnosed with dyslexia (aged between 8 and 14 years) underwent two ICT sessions a week, with home supplements, for a duration of 7 months. The participants showed a significant improvement in the reading speed of text, words, and non-words, and in the reading accuracy of text and non-words. In Experiment 2, we replicated Experiment 1, but included a comparison between two groups (experimental group vs. control group) of young participants with diagnosis of dyslexia. The experimental group was subjected to 18 ICT sessions twice a week and with home supplements, using the same protocol as in Experiment 1. The control group was entrusted to the protocol of compensatory tools and dispense/helping procedures provided by the scholastic Personalized Educational Plan. After training, the experimental group gained about 0.5 syllables per second in text reading, and a marked decrease in error rate. The control group showed no significant improvement in reading skills after the same period. Moreover, the improvement observed in the experimental group remained stable 4 months after ICT had ended. The results of these two experiments support the efficacy of the integrated ICT protocol in improving reading skills in children with dyslexia and its sustained effect.
Collapse
Affiliation(s)
- Francesco Benso
- Department of Psychology and Cognitive Sciences, University of Trento, Rovereto, Italy.,ANCCRI, Associazione Neuroscienze Cognitive Clinica Ricerca e Intervento, Genova, Italy.,AIDAI Liguria, Associazione Italiana per i Disturbi di Attenzione e Iperattività, Liguria, Italy
| | - Sandra Moretti
- ANCCRI, Associazione Neuroscienze Cognitive Clinica Ricerca e Intervento, Genova, Italy.,AIDAI Liguria, Associazione Italiana per i Disturbi di Attenzione e Iperattività, Liguria, Italy.,ASL 5, Azienda Sanitaria Locale, La Spezia, Italy
| | - Veronica Bellazzini
- ANCCRI, Associazione Neuroscienze Cognitive Clinica Ricerca e Intervento, Genova, Italy.,AIDAI Liguria, Associazione Italiana per i Disturbi di Attenzione e Iperattività, Liguria, Italy
| | - Eva Benso
- ANCCRI, Associazione Neuroscienze Cognitive Clinica Ricerca e Intervento, Genova, Italy
| | - Eleonora Ardu
- ANCCRI, Associazione Neuroscienze Cognitive Clinica Ricerca e Intervento, Genova, Italy
| | - Simone Gazzellini
- Department of Intensive and Robotic Neurorehabilitation, Bambino Gesù Children's Hospital Institute of Recovery and Care Caracterized by Research, Rome, Italy
| |
Collapse
|
4
|
Vanderauwera J, Altarelli I, Vandermosten M, De Vos A, Wouters J, Ghesquière P. Atypical Structural Asymmetry of the Planum Temporale is Related to Family History of Dyslexia. Cereb Cortex 2018; 28:63-72. [PMID: 29253247 DOI: 10.1093/cercor/bhw348] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Indexed: 11/14/2022] Open
Abstract
Research on the neural correlates of developmental dyslexia indicates atypical anatomical lateralization of the planum temporale, a higher-order cortical auditory region. Yet whether this atypical lateralization precedes reading acquisition and is related to a familial risk for dyslexia is not currently known. In this study, we address these questions in 2 separate cohorts of young children and adolescents with and without a familial risk for dyslexia. Planum temporale surface area was manually labeled bilaterally, on the T1-weighted MR brain images of 54 pre-readers (mean age: 6.2 years, SD: 3.2 months; 33 males) and 28 adolescents (mean age: 14.7 years, SD: 3.3 months; 11 males). Half of the pre-readers and adolescents had a familial risk for dyslexia. In both pre-readers and adolescents, group comparisons of left and right planum temporale surface area showed a significant interaction between hemisphere and family history of dyslexia, with participants who had no family risk for dyslexia showing greater leftward asymmetry of the planum temporale. This effect was confirmed when analyses were restricted to normal reading participants. Altered planum temporale asymmetry thus seems to be related to family history of dyslexia.
Collapse
Affiliation(s)
- Jolijn Vanderauwera
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.,Research Group ExpORL, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Maaike Vandermosten
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.,Research Group ExpORL, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Astrid De Vos
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.,Research Group ExpORL, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Jan Wouters
- Research Group ExpORL, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Pol Ghesquière
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Cappa C, Giulivi S, Schilirò A, Bastiani L, Muzio C, Meloni F. A screening on Specific Learning Disorders in an Italian speaking high genetic homogeneity area. RESEARCH IN DEVELOPMENTAL DISABILITIES 2015; 45-46:329-342. [PMID: 26296080 DOI: 10.1016/j.ridd.2015.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 07/09/2015] [Accepted: 07/13/2015] [Indexed: 06/04/2023]
Abstract
The aim of the present research is to investigate the prevalence of Specific Learning Disorders (SLD) in Ogliastra, an area of the island of Sardinia, Italy. Having experienced centuries of isolation, Ogliastra has become a high genetic homogeneity area, and is considered particularly interesting for studies on different kinds of pathologies. Here we are going to describe the results of a screening carried out throughout 2 consecutive years in 49 second grade classes (24 considered in the first year and 25 in the second year of the study) of the Ogliastra region. A total of 610 pupils (average age 7.54 years; 293 female, 317 male) corresponding to 68.69% of all pupils who were attending second grade in the area, took part in the study. The tool used for the screening was "RSR-DSA. Questionnaire for the detection of learning difficulties and disorders", which allowed the identification of 83 subjects at risk (13.61% of the whole sample involved in the study). These subjects took part in an enhancement training program of about 6 months. After the program, pupils underwent assessment for reading, writing and calculation abilities, as well as cognitive assessment. According to the results of the assessment, the prevalence of SLDs is 6.06%. For what concerns dyslexia, 4.75% of the total sample manifested this disorder either in isolation or in comorbidity with other disorders. According to the first national epidemiological investigation carried out in Italy, the prevalence of dyslexia is 3.1-3.2%, which is lower than the prevalence obtained in the present study. Given the genetic basis of SLDs, this result, together with the presence of several cases of SLD in isolation (17.14%) and with a 3:1 ratio of males to females diagnosed with a SLD, was to be expected in a sample coming from a high genetic homogeneity area.
Collapse
Affiliation(s)
- Claudia Cappa
- Institute of Clinical Physiology (IFC), CNR, Pisa, Italy.
| | - Sara Giulivi
- Department of Teaching and Learning (DFA) - University School of Applied Sciences and Arts of Southern Switzerland (SUPSI), Locarno, Switzerland.
| | - Antonino Schilirò
- Service of Child Neuropsychiatry, Azienda Sanitaria Locale 4, Lanusei, Italy.
| | - Luca Bastiani
- Institute of Clinical Physiology (IFC), CNR, Pisa, Italy.
| | - Carlo Muzio
- Istituto Santo Stefano, Porto Potenza Picena (MC), Italy.
| | - Fabrizio Meloni
- Service of Child Neuropsychiatry, Azienda Sanitaria Locale 4, Lanusei, Italy.
| |
Collapse
|
7
|
Ma Y, Koyama MS, Milham MP, Castellanos FX, Quinn BT, Pardoe H, Wang X, Kuzniecky R, Devinsky O, Thesen T, Blackmon K. Cortical thickness abnormalities associated with dyslexia, independent of remediation status. Neuroimage Clin 2014; 7:177-86. [PMID: 25610779 PMCID: PMC4300011 DOI: 10.1016/j.nicl.2014.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 10/18/2014] [Accepted: 11/11/2014] [Indexed: 11/11/2022]
Abstract
Abnormalities in cortical structure are commonly observed in children with dyslexia in key regions of the "reading network." Whether alteration in cortical features reflects pathology inherent to dyslexia or environmental influence (e.g., impoverished reading experience) remains unclear. To address this question, we compared MRI-derived metrics of cortical thickness (CT), surface area (SA), gray matter volume (GMV), and their lateralization across three different groups of children with a historical diagnosis of dyslexia, who varied in current reading level. We compared three dyslexia subgroups with: (1) persistent reading and spelling impairment; (2) remediated reading impairment (normal reading scores), and (3) remediated reading and spelling impairments (normal reading and spelling scores); and a control group of (4) typically developing children. All groups were matched for age, gender, handedness, and IQ. We hypothesized that the dyslexia group would show cortical abnormalities in regions of the reading network relative to controls, irrespective of remediation status. Such a finding would support that cortical abnormalities are inherent to dyslexia and are not a consequence of abnormal reading experience. Results revealed increased CT of the left fusiform gyrus in the dyslexia group relative to controls. Similarly, the dyslexia group showed CT increase of the right superior temporal gyrus, extending into the planum temporale, which resulted in a rightward CT asymmetry on lateralization indices. There were no group differences in SA, GMV, or their lateralization. These findings held true regardless of remediation status. Each reading level group showed the same "double hit" of atypically increased left fusiform CT and rightward superior temporal CT asymmetry. Thus, findings provide evidence that a developmental history of dyslexia is associated with CT abnormalities, independent of remediation status.
Collapse
Affiliation(s)
- Yizhou Ma
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
- Department of Psychology, New York University, New York, NY, USA
| | - Maki S. Koyama
- Child Mind Institute, New York, NY, USA
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Michael P. Milham
- Child Mind Institute, New York, NY, USA
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - F. Xavier Castellanos
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
- Child Study Center at NYU Langone Medical Center, New York, NY, USA
- Department of Radiology, School of Medicine, New York University, New York, NY, USA
| | - Brian T. Quinn
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
| | - Heath Pardoe
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
| | - Xiuyuan Wang
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
| | - Ruben Kuzniecky
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
| | - Orrin Devinsky
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
| | - Thomas Thesen
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
- Department of Radiology, School of Medicine, New York University, New York, NY, USA
| | - Karen Blackmon
- Department of Neurology, Comprehensive Epilepsy Center, School of Medicine, New York University, New York, NY, USA
| |
Collapse
|
8
|
Altarelli I, Leroy F, Monzalvo K, Fluss J, Billard C, Dehaene-Lambertz G, Galaburda AM, Ramus F. Planum temporale asymmetry in developmental dyslexia: Revisiting an old question. Hum Brain Mapp 2014; 35:5717-35. [PMID: 25044828 DOI: 10.1002/hbm.22579] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/10/2014] [Accepted: 06/25/2014] [Indexed: 11/06/2022] Open
Abstract
Among the various asymmetrical structures of the human brain, the planum temporale, an anatomical region associated with a variety of auditory and language-related processes, has received particular attention. While its surface area has been shown to be greater in the left hemisphere compared to the right in about two-thirds of the general population, altered patterns of asymmetry were revealed by post mortem analyses in individuals with developmental dyslexia. These findings have been inconsistently replicated in magnetic resonance imaging studies of this disorder. In this report, we attempt to resolve past inconsistencies by analyzing the T1-weighted MR images of 81 children (mean age: 11 years, sd: 17 months), including 46 control (25 boys) and 35 dyslexic children (20 boys). We manually outlined Heschl's gyri, the planum temporale and the posterior rami of the Sylvian fissure on participants' brain images, using the same anatomical criteria as in post mortem studies. Results revealed an altered pattern of asymmetry of the planum temporale surface area in dyslexic boys only, with a greater proportion of rightward asymmetrical cases among dyslexic boys compared to control boys. Additionally, analyses of cortical thickness showed no asymmetry differences between groups for any of the regions of interest. Finally, a greater number of Heschl's gyrus full duplications emerged for the right hemisphere of dyslexic boys compared to controls. The present findings confirm and extend early post mortem observations. They also stress the importance of taking gender into account in studies of developmental dyslexia.
Collapse
Affiliation(s)
- Irene Altarelli
- Laboratoire de Sciences Cognitives et Psycholinguistique, Département d'Etudes Cognitives, Ecole Normale Supérieure, EHESS, CNRS, PSL Research University, 75230, Paris Cedex 05, France; Brain and Learning Laboratory, FPSE, University of Geneva, 1211, Geneva 4, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Dole M, Meunier F, Hoen M. Gray and white matter distribution in dyslexia: a VBM study of superior temporal gyrus asymmetry. PLoS One 2013; 8:e76823. [PMID: 24098565 PMCID: PMC3788100 DOI: 10.1371/journal.pone.0076823] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 09/03/2013] [Indexed: 01/18/2023] Open
Abstract
In the present study, we investigated brain morphological signatures of dyslexia by using a voxel-based asymmetry analysis. Dyslexia is a developmental disorder that affects the acquisition of reading and spelling abilities and is associated with a phonological deficit. Speech perception disabilities have been associated with this deficit, particularly when listening conditions are challenging, such as in noisy environments. These deficits are associated with known neurophysiological correlates, such as a reduction in the functional activation or a modification of functional asymmetry in the cortical regions involved in speech processing, such as the bilateral superior temporal areas. These functional deficits have been associated with macroscopic morphological abnormalities, which potentially include a reduction in gray and white matter volumes, combined with modifications of the leftward asymmetry along the perisylvian areas. The purpose of this study was to investigate gray/white matter distribution asymmetries in dyslexic adults using automated image processing derived from the voxel-based morphometry technique. Correlations with speech-in-noise perception abilities were also investigated. The results confirmed the presence of gray matter distribution abnormalities in the superior temporal gyrus (STG) and the superior temporal Sulcus (STS) in individuals with dyslexia. Specifically, the gray matter of adults with dyslexia was symmetrically distributed over one particular region of the STS, the temporal voice area, whereas normal readers showed a clear rightward gray matter asymmetry in this area. We also identified a region in the left posterior STG in which the white matter distribution asymmetry was correlated to speech-in-noise comprehension abilities in dyslexic adults. These results provide further information concerning the morphological alterations observed in dyslexia, revealing the presence of both gray and white matter distribution anomalies and the potential involvement of these defects in speech-in-noise deficits.
Collapse
Affiliation(s)
- Marjorie Dole
- Laboratoire de Psychologie et NeuroCognition, CNRS UMR 5105, université Pierre Mendès France, Grenoble, France
- * E-mail:
| | - Fanny Meunier
- L2C2, CNRS UMR 5304, Institut des Sciences Cognitives, Lyon, France
- Université de Lyon, Université Lyon 1, Lyon, France
| | - Michel Hoen
- INSERM U1028, Lyon Neuroscience Research Center, Brain Dynamics and Cognition Team, Lyon, France
- CNRS UMR 5292, Lyon Neuroscience Research Center, Brain Dynamics and Cognition Team, Lyon, France
- Université de Lyon, Université Lyon 1, Lyon, France
| |
Collapse
|
10
|
Yates R. Bad mouthing, bad habits and bad, bad, boys: an exploration of the relationship between dyslexia and drug dependence. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/17523281.2012.699460] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
11
|
Chiarello C, Welcome SE, Leonard CM. Individual differences in reading skill and language lateralisation: a cluster analysis. Laterality 2011; 17:225-51. [PMID: 22385144 PMCID: PMC3296279 DOI: 10.1080/1357650x.2011.561860] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Individual differences in reading and cerebral lateralisation were investigated in 200 college students who completed reading assessments and divided visual field word recognition tasks, and received a structural MRI scan. Prior studies on this data set indicated that little variance in brain-behaviour correlations could be attributed to the effects of sex and handedness variables (Chiarello, Welcome, Halderman, & Leonard, 2009; Chiarello, Welcome, Halderman, Towler, et al., 2009; Welcome et al., 2009). Here a more bottom-up approach to behavioural classification (cluster analysis) was used to explore individual differences that need not depend on a priori decisions about relevant subgroups. The cluster solution identified four subgroups of college age readers with differing reading skill and visual field lateralisation profiles. These findings generalised to measures that were not included in the cluster analysis. Poorer reading skill was associated with somewhat reduced VF asymmetry, while average readers demonstrated exaggerated RVF/left hemisphere advantages. Skilled readers had either reduced asymmetries, or asymmetries that varied by task. The clusters did not differ by sex or handedness, suggesting that there are identifiable sources of variance among individuals that are not captured by these standard participant variables. All clusters had typical leftward asymmetry of the planum temporale. However, the size of areas in the posterior corpus callosum distinguished the two subgroups with high reading skill. A total of 17 participants, identified as multivariate outliers, had unusual behavioural profiles and differed from the remainder of the sample in not having significant leftward asymmetry of the planum temporale. A less buffered type of neurodevelopment that is more open to the effects of random genetic and environmental influences may characterise such individuals.
Collapse
Affiliation(s)
- Christine Chiarello
- Department of Psychology, University of California, Riverside, Riverside, CA 92521, USA.
| | | | | |
Collapse
|
12
|
Castles A, M T McLean G, McArthur G. Dyslexia (neuropsychological). WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2010; 1:426-432. [PMID: 26271382 DOI: 10.1002/wcs.16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this article, we review research into the underlying deficits associated with the failure to learn to read normally, or developmental dyslexia. We focus on the heterogeneity within this broad category of disorder and on the relationship between the proposed deficits and the acquisition of specific kinds of reading skill. We also distinguish between 'high-level' cognitive or language deficits associated with developmental dyslexia and 'low-level' perceptual or neurological deficits. We conclude that the mixed and sometimes contradictory sets of findings associated with most of the proposed deficits reveal something important: that there is no single cause of developmental dyslexia and that it is likely that multiple causes interact in complex ways to impair reading acquisition. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.
Collapse
Affiliation(s)
- Anne Castles
- Macquarie Centre for Cognitive Science, Macquarie University, Australia
| | - Gregor M T McLean
- Macquarie Centre for Cognitive Science, Macquarie University, Australia
| | | |
Collapse
|
13
|
Caylak E. Neurobiological approaches on brains of children with dyslexia: review. Acad Radiol 2009; 16:1003-24. [PMID: 19406674 DOI: 10.1016/j.acra.2009.02.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Revised: 02/08/2009] [Accepted: 02/10/2009] [Indexed: 02/05/2023]
Abstract
Learning difficulties commonly comprise a heterogeneous group of disorders manifested by unexpected problems in some children's experiences in the academic performance arena. These problems especially comprise of a variety of disorders, which one of the most well-recognized learning difficulties is reading disability or dyslexia. The aim of this review is to explain the postmortem, structural or functional neuroimaging, and electrophysiological studies of human brains in children. The findings about these neuropathological and neurofunctional characteristics of developmental dyslexia, prospective studies beginning early in the life span and studies targeting remedial intervention will help to set the research agendas for future studies to follow.
Collapse
Affiliation(s)
- Emrah Caylak
- Department of Biochemistry and Clinical Biochemistry, Firat University, School of Medicine, Elazig, Turkey.
| |
Collapse
|
14
|
Abstract
The unique human ability of linguistic communication, defined as the ability to produce a practically infinite number of meaningful messages using a finite number of lexical items, is determined by an array of "linguistic" genes, which are expressed in neurons forming domain-specific linguistic centers in the brain. In this review, I discuss the idea that infants' early language experience performs two complementary functions. In addition to allowing infants to assimilate the words and grammar rules of their mother language, early language experience initiates genetic programs underlying language production and comprehension. This hypothesis explains many puzzling characteristics of language acquisition, such as the existence of a critical period for acquiring the first language and the absence of a critical period for the acquisition of additional language(s), a similar timetable for language acquisition in children belonging to families of different social and cultural status, the strikingly similar timetables in the acquisition of oral and sign languages, and the surprisingly small correlation between individuals' final linguistic competence and the intensity of their training. Based on the studies of microcephalic individuals, I argue that genetic factors determine not only the number of neurons and organization of interneural connections within linguistic centers, but also the putative internal properties of neurons that are not limited to their electrophysiological and synaptic properties.
Collapse
Affiliation(s)
- Yuri I Arshavsky
- Institute for Nonlinear Science, University of California San Diego, La Jolla, CA 92093-0402, USA.
| |
Collapse
|
15
|
Abstract
Developmental language disorders are characterized by a maturational trajectory that deviates or lags that of normal children. Given the wide variation in the rate of normal language development, diagnosis and classification of these disorders poses severe problems for the clinician. Our laboratory has been searching for anatomical signatures that could aid the development of a neurobiologically based classification. Quantitative analysis of the magnetic resonance imaging (MRI) brain scans of a series of samples of children and adults with reading and language disorders has identified two clusters with contrasting anatomical and reading profiles. Individuals with small symmetrical brain structures tend to have deficits in multiple domains of written and oral language whereas those with larger asymmetrical structures are more likely to have the isolated phonological deficits seen in adults with compensated dyslexia. Surprisingly, the anatomical risk factors that define these clusters do not form a continuum of increasing severity but deviate in opposite directions from normal. Individuals with moderate brain size and asymmetry typically demonstrate the best overall performance. Further research should determine if phonological impairments in the two clusters are associated with differing genetic and environmental risk factors requiring different types of intervention.
Collapse
Affiliation(s)
- Christiana M Leonard
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Health Science Center, Gainesville FL 32610, USA.
| | | |
Collapse
|
16
|
Leonard CM, Towler S, Welcome S, Halderman LK, Otto R, Eckert MA, Chiarello C. Size matters: cerebral volume influences sex differences in neuroanatomy. Cereb Cortex 2008; 18:2920-31. [PMID: 18440950 PMCID: PMC2583156 DOI: 10.1093/cercor/bhn052] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Biological and behavioral differences between the sexes range from obvious to subtle or nonexistent. Neuroanatomical differences are particularly controversial, perhaps due to the implication that they might account for behavioral differences. In this sample of 200 men and women, large effect sizes (Cohen's d > 0.8) were found for sex differences in total cerebral gray and white matter, cerebellum, and gray matter proportion (women had a higher proportion of gray matter). The only one of these sex differences that survived adjustment for the effect of cerebral volume was gray matter proportion. Individual differences in cerebral volume accounted for 21% of the difference in gray matter proportion, while sex accounted for an additional 4%. The relative size of the corpus callosum was 5% larger in women, but this difference was completely explained by a negative relationship between relative callosal size and cerebral volume. In agreement with Jancke et al., individuals with higher cerebral volume tended to have smaller corpora callosa. There were few sex differences in the size of structures in Broca's and Wernicke's area. We conclude that individual differences in brain volume, in both men and women, account for apparent sex differences in relative size.
Collapse
|
17
|
Abstract
Optometrists will frequently see patients, who may have a diagnosis or a suspected diagnosis of dyslexia (specific reading disorder) and will need to manage and counsel such patients. There are many propounded theories on the cause(s) of dyslexia. Although most professionals in this area consider that dyslexia is chiefly a linguistic disorder, the possibility of a visual component is contentious. This article is a selective review of two commonly discussed theories that suggest a visual component in dyslexia; the magnocellular deficit theory and Meares-Irlen syndrome.
Collapse
|
18
|
Eckert MA, Lombardino LJ, Walczak AR, Bonihla L, Leonard CM, Binder JR. Manual and automated measures of superior temporal gyrus asymmetry: concordant structural predictors of verbal ability in children. Neuroimage 2008; 41:813-22. [PMID: 18440244 DOI: 10.1016/j.neuroimage.2008.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 02/28/2008] [Accepted: 03/03/2008] [Indexed: 11/19/2022] Open
Abstract
The planum temporale is a region on the posterior surface of the temporal lobe that exhibits robust leftward structural asymmetry, which has been linked to verbal ability in children and adults. Traditionally, structural asymmetry has been quantified with manual assessment of high resolution MRI scans. Such measures require subjective and frequently unreliable determination of highly variable anatomical boundaries. Methodological developments in automated image processing (voxel-based morphometry - VBM) offer the opportunity to obtain objective and reliable measures of structural variation. This study examined the extent to which a VBM measure of gray matter asymmetry in the posterior superior temporal gyrus (pSTG) characterized the same individual variation as a manual measure of planum temporale asymmetry in 99 healthy adults and 39 typically developing children. Planum temporale asymmetry was significantly correlated with pSTG gray matter asymmetry in the samples of adults and children. As a measure of validity we examined the extent to which the VBM measure of pSTG gray matter asymmetry predicted measures of verbal ability that were associated with the manual measure of planum temporale asymmetry in the same children. The two asymmetry measures predicted the same variance in verbal ability. The automated measure of pSTG gray matter asymmetry predicted additional significant variance in verbal ability, however. In addition, a posterior STS region was also identified that significantly predicted verbal ability. These results demonstrate significant advantages of an automated voxel-based measure over a manual measure of planum temporale asymmetry.
Collapse
Affiliation(s)
- Mark A Eckert
- Medical University of South Carolina, Department of Otolaryngology, Head and Neck Surgery, SC 29425, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Eckert MA, Galaburda AM, Karchemskiy A, Liang A, Thompson P, Dutton RA, Lee AD, Bellugi U, Korenberg JR, Mills D, Rose FE, Reiss AL. Anomalous sylvian fissure morphology in Williams syndrome. Neuroimage 2006; 33:39-45. [PMID: 16876437 DOI: 10.1016/j.neuroimage.2006.05.062] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 05/10/2006] [Accepted: 05/12/2006] [Indexed: 11/28/2022] Open
Abstract
The unusual sensitivity and attraction to auditory stimuli in people with Williams syndrome (WS) has been hypothesized to be the consequence of atypical development of brain regions surrounding the Sylvian fissure. Planum temporale surface area, which is determined in part by Sylvian fissure patterning, was examined in 42 WS and 40 control participants to determine if anomalous Sylvian fissure morphology is present in WS. WS participants had significantly reduced leftward asymmetry of the planum temporale compared to control participants, due to a significant expansion in the size of the right planum temporale. The increased right planum temporale size was largely due to WS participants (24%) who had a right hemisphere Sylvian fissure that coursed horizontally and failed to ascend into the parietal lobe. This sulcal pattern is unusual in the right hemisphere and is more commonly found in the left hemisphere of typically developing individuals. There were no control participants with this type of right hemisphere Sylvian fissure pattern. The right hemisphere Sylvian fissure sulcal patterns were also related to a measure of cortical complexity and the amount of right hemisphere occipital lobe volume, suggesting that intrinsic genetic influences leading to anomalous visual system development in WS have widespread influences on cortical morphology that are similar in manner to extrinsic embryonic visual system lesions.
Collapse
Affiliation(s)
- Mark A Eckert
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, 29425, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Eckert MA, Leonard CM, Possing ET, Binder JR. Uncoupled leftward asymmetries for planum morphology and functional language processing. BRAIN AND LANGUAGE 2006; 98:102-11. [PMID: 16697453 PMCID: PMC1661833 DOI: 10.1016/j.bandl.2006.04.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 03/23/2006] [Accepted: 04/02/2006] [Indexed: 05/09/2023]
Abstract
Explanations for left hemisphere language laterality have often focused on hemispheric structural asymmetry of the planum temporale. We examined the association between an index of language laterality and brain morphology in 99 normal adults whose degree of laterality was established using a functional MRI single-word comprehension task. The index of language laterality was derived from the difference in volume of activation between the left and right hemispheres. Planum temporale and brain volume measures were made using structural MRI scans, blind to the functional data. Although both planum temporale asymmetry (t(1,99) = 6.86, p < .001) and language laterality (t(1,99) = 15.26, p < .001) were significantly left hemisphere biased, there was not a significant association between these variables (r(99) = .01,ns). Brain volume, a control variable for the planum temporale analyses, was related to language laterality in a multiple regression (beta = -.30, t = -2.25, p < .05). Individuals with small brains were more likely to demonstrate strong left hemisphere language laterality. These results suggest that language laterality is a multidimensional construct with complex neurological origins.
Collapse
Affiliation(s)
- Mark A Eckert
- Medical University of South Carolina, Department of Otolaryngology-Head and Neck Surgery, USA.
| | | | | | | |
Collapse
|
21
|
Arshavsky YI. “Scientific roots” of dualism in neuroscience. Prog Neurobiol 2006; 79:190-204. [PMID: 16935408 DOI: 10.1016/j.pneurobio.2006.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2006] [Revised: 07/14/2006] [Accepted: 07/18/2006] [Indexed: 01/04/2023]
Abstract
Although the dualistic concept is unpopular among neuroscientists involved in experimental studies of the brain, neurophysiological literature is full of covert dualistic statements on the possibility of understanding neural mechanisms of human consciousness. Particularly, the covert dualistic attitude is exhibited in the unwillingness to discuss neural mechanisms of consciousness, leaving the problem of consciousness to psychologists and philosophers. This covert dualism seems to be rooted in the main paradigm of neuroscience that suggests that cognitive functions, such as language production and comprehension, face recognition, declarative memory, emotions, etc., are performed by neural networks consisting of simple elements. I argue that neural networks of any complexity consisting of neurons whose function is limited to the generation of electrical potentials and the transmission of signals to other neurons are hardly capable of producing human mental activity, including consciousness. Based on results obtained in physiological, morphological, clinical, and genetic studies of cognitive functions (mainly linguistic ones), I advocate the hypothesis that the performance of cognitive functions is based on complex cooperative activity of "complex" neurons that are carriers of "elementary cognition." The uniqueness of human cognitive functions, which has a genetic basis, is determined by the specificity of genes expressed by these "complex" neurons. The main goal of the review is to show that the identification of the genes implicated in cognitive functions and the understanding of a functional role of their products is a possible way to overcome covert dualism in neuroscience.
Collapse
Affiliation(s)
- Yuri I Arshavsky
- Institute for Nonlinear Science, University of California San Diego, La Jolla, CA 92093-0402, USA.
| |
Collapse
|
22
|
Rojas DC, Camou SL, Reite ML, Rogers SJ. Planum temporale volume in children and adolescents with autism. J Autism Dev Disord 2005; 35:479-86. [PMID: 16134033 DOI: 10.1007/s10803-005-5038-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Previous research has revealed a lack of planum temporale (PT) asymmetry in adults with autism. This finding is now extended to children and adolescents with the disorder. MRI scans were obtained from 12 children with autism and 12 gender, handedness and age-matched comparison participants. The volume of gray matter in the PT and Heschl's gyrus (HG) in both hemispheres was measured. PT volume was larger in the left hemisphere than in the right in the comparison, but not the autism group. This specifically reflected reduced volume of the left PT in the autism group. There were noted differences in the overall morphological appearance of the right Sylvian fissure in the autism group, but no volumetric difference in the right PT. No differences in HG volumes were observed between the two groups. Lack of PT asymmetry may suggest an early neurodevelopmental disturbance in autism.
Collapse
Affiliation(s)
- Donald C Rojas
- Department of Psychiatry, University of Colorado Health Sciences Center, Box C268-68 CPH Rm. 2J08, Denver, CO, USA.
| | | | | | | |
Collapse
|
23
|
Galaburda AM. Dyslexia--a molecular disorder of neuronal migration: the 2004 Norman Geschwind Memorial Lecture. ANNALS OF DYSLEXIA 2005; 55:151-65. [PMID: 17849191 DOI: 10.1007/s11881-005-0009-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2005] [Accepted: 09/12/2005] [Indexed: 05/17/2023]
Abstract
For 25 years now, there has been a serious attempt to get at the fundamental cause(s) of dyslexia in our laboratory. A great deal of research has been carried out on the psychological and brain underpinnings of the linguistic dysfunctions seen in dyslexia, but attempts to get at its cause have been limited. Initially, observations were made on the brains of persons with dyslexia who had died and their brains donated for research. These observations were modeled in animal models in order to better understand the full extent of anatomical and developmental brain characteristics. More recently, models have begun to employ genetic manipulations in order to close the gap between genes, brain, and behavior. In this article based on a lecture given in memory of Dr. Norman Geschwind to the International Dyslexia Association assembly in Philadelphia in 2004, I outline the history of the research leading up to the most recent findings. These findings consist of experiments using methods that interfere with the function of DNA, using as constructs genes that have been implicated in dyslexia, which cause developmental problems of neuronal migration in rats, secondary brain changes in response to the migration problems, and abnormal processing of sounds.
Collapse
Affiliation(s)
- Albert M Galaburda
- Harvard Medical School, Division of Behavioral Neurology and Memory Disorders, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
| |
Collapse
|
24
|
Eckert MA, Leonard CM, Wilke M, Eckert M, Richards T, Richards A, Berninger V. Anatomical signatures of dyslexia in children: unique information from manual and voxel based morphometry brain measures. Cortex 2005; 41:304-15. [PMID: 15871596 DOI: 10.1016/s0010-9452(08)70268-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Thirteen male control and thirteen male dyslexic children (age, 121-152 months) were studied to determine if voxel based morphometry (VBM) could identify anatomical differences in the right cerebellar anterior lobe, and right and left pars triangularis that were identified with manual measures of the same children. VBM demonstrated significant gray and white matter differences in these three brain regions. In contrast to the manual results, these differences were not significant after controlling for brain volume, suggesting the manual measures captured additional important variance that distinguished the groups. Post-hoc VBM comparisons demonstrated white matter volume differences in a left temporal-parietal region that are consistent in location with results from diffusion tensor imaging studies of dyslexia. The VBM analyses also identified, gray matter volume differences in the left and right lingual gyrus, left inferior parietal lobule and cerebellum, areas that had not been examined with manual methods. We conclude that manual and automated methods provide valuable and complementary approaches to the search for functionally significant neurobiological characteristics of dyslexia.
Collapse
Affiliation(s)
- Mark A Eckert
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, CA 94305, USA.
| | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
A neuroanatomical description of dyslexia has been elusive, due in part to the complex cognitive nature of dyslexia. People with dyslexia have varying degrees of impairment in reading skills that engage oral and written language (reading) neural networks. Although findings for the inferior parietal lobule, inferior frontal gyrus, and cerebellum have been relatively consistent across studies, these studies also demonstrate that anatomical patterns of results vary according to the reading skills that characterize dyslexia. The number and likelihood of atypical anatomical findings in oral and/or written language systems appears to be related to the pattern of impairments in measures of phonology, orthography, and fluency. A comprehensive neurobiological understanding of dyslexia will depend on studies of dyslexic individuals with homogeneous perceptual, cognitive, and genetic backgrounds.
Collapse
Affiliation(s)
- Mark Eckert
- Department of Child and Adolescent Psychiatry, Stanford University, Palo Alto, CA 94305, USA.
| |
Collapse
|
26
|
Chiarello C, Kacinik N, Manowitz B, Otto R, Leonard C. Cerebral Asymmetries for Language: Evidence for Structural-Behavioral Correlations. Neuropsychology 2004; 18:219-31. [PMID: 15099144 DOI: 10.1037/0894-4105.18.2.219] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The current investigation tested 20 male right-handers in 5 divided visual field lexical tasks. Asymmetries in Heschl's gyrus, planum temporale, and planum parietale were measured using structural magnetic resonance imaging. Composite task asymmetries were positively correlated with asymmetry of the planum temporale only. There was also an association between the consistency of anatomical and behavioral asymmetries: Individuals who departed the most from the modal pattern of cortical asymmetry across regions also tended to show the greatest variability in asymmetry across tasks. Hence, individual differences in language laterality tasks may be affected by variation in asymmetry of posterior language structures. Additionally, when typical anatomical asymmetries fail to co-occur, there may be a less strictly regulated distribution of function across hemispheres.
Collapse
Affiliation(s)
- Christine Chiarello
- Department of Psychology, University of California, Riverside, CA 92521, USA.
| | | | | | | | | |
Collapse
|
27
|
Leonard CM, Lombardino LJ, Walsh K, Eckert MA, Mockler JL, Rowe LA, Williams S, DeBose CB. Anatomical risk factors that distinguish dyslexia from SLI predict reading skill in normal children. JOURNAL OF COMMUNICATION DISORDERS 2002; 35:501-531. [PMID: 12443050 DOI: 10.1016/s0021-9924(02)00120-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
UNLABELLED These studies investigated whether anatomical measures could separate phonologically-based reading disability (PD) from nonphonologically-based learning disabilities such as specific language impairment (SLI). In a previous study. four brain measures (cerebral asymmetry. summed planum temporale and parietale asymmetry, anterior cerebellar asymmetry, and a duplicated left Heschl's gyrus) distinguished a group of PD adults from reading disabled adults without specific phonological deficits (URD). Study 1 found that these measures did not distinguish 14 reading disabled children from 21 children with SLI. Instead, differences were found in cerebral volume, planum temporale asymmetry, and the size of a single left Heschl's gyrus. Study 2 demonstrated that including all seven measures in a discriminant analysis separated the adults and children into two groups: one with 100% of the PD adults and 75% of the reading disabled children and the other with 72% of the SLI children and 75% of the URD adults. Study 3 demonstrated that an anatomical risk factor index (ARF7) generated from the discriminant function with seven brain measures predicted reading in normal children. Children with ARF7 near 0 (normal anatomy) had superior verbal ability and phonological decoding scores that improved with age. Normal children with negative ARF7 the relatively s mall symmetrical structures that characterize SLI)had deficits in verbal ability. Children with positive ARF7 (the asymmetrical structures that characterize PD) had phonological decoding scores that decreased with age. These results suggest that PD and SLI are qualitatively different disorders associated with anatomical deviations in opposite directions from the population mean. LEARNING OUTCOMES As a result of this activity, the participant will be able to: (1) distinguish the neuroanatomical features that characterize PD and SLI; (2) recognize that PD is associated with large asymmetrical brain structures while SLI is associated with smaller symmetrical brain structures; (3) understand that children with moderate sized brains and whose anatomy is intermediate between symmetry and extreme asymmetry have an enhanced probability of developing good verbal ability; (4) understand that reading disabilities depend on the interaction of neurodevelopment and the environment.
Collapse
Affiliation(s)
- Christiana M Leonard
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville 32611, USA.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Eckert MA, Leonard CM, Molloy EA, Blumenthal J, Zijdenbos A, Giedd JN. The epigenesis of planum temporale asymmetry in twins. Cereb Cortex 2002; 12:749-55. [PMID: 12050086 PMCID: PMC2739006 DOI: 10.1093/cercor/12.7.749] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Variation in hemispheric asymmetry of the planum temporale (PT) has been related to verbal ability. The degree to which genetic and environmental factors mediate PT asymmetry is not known. This study examined the heritability for planar asymmetry in 12 dizygotic (DZ) and 27 monozygotic (MZ) male twin pairs who were between 6 and 16 years of age. There was weak but positive evidence for heritability of planar asymmetry. Co-twin similarity for planar asymmetry and Sylvian fissure morphology increased when excluding twins discordant for writing hand and when excluding twins exhibiting birth weight differences >20% from the analyses. Birth weight differences were also related to twin differences in total cerebral volume, but not central sulcus asymmetry. These results suggest that exogenous perinatal factors affect the epigenesis of planar asymmetry development.
Collapse
Affiliation(s)
- Mark A Eckert
- Department of Neuroscience, McKnight Brain Institute of the University of Florida, Gainesville, FL 32610, USA.
| | | | | | | | | | | |
Collapse
|
29
|
Trauzettel-Klosinski S, MacKeben M, Reinhard J, Feucht A, Dürrwächter U, Klosinski G. Pictogram naming in dyslexic and normal children assessed by SLO. Vision Res 2002; 42:789-99. [PMID: 11888544 DOI: 10.1016/s0042-6989(01)00318-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We measured pictogram naming (PN) and text reading in dyslexic and normally reading young teenagers. Eye movements were monitored by scanning laser ophthalmoscope, revealing positions of fovea, stimuli on the retina, and speech simultaneously. While text reading speed showed the expected difference between groups, PN speeds overlapped widely. PN was mainly controlled by retrieval time in both groups and correlated with age in dyslexics. During PN, only backward saccades occurred more frequently in dyslexics. We conclude that PN activates visual/eidetic mechanisms that are distinct from the phonemic/analytic pathway necessary for reading. This dual organization leads to a wide range of combinations of performances in PN and text reading.
Collapse
Affiliation(s)
- Susanne Trauzettel-Klosinski
- Department of Pathophysiology of Vision and Neuroophthalmology, University Eye Hospital, 72076 Tübingen, Germany.
| | | | | | | | | | | |
Collapse
|
30
|
Eckert MA, Leonard CM. Structural imaging in dyslexia: the planum temporale. MENTAL RETARDATION AND DEVELOPMENTAL DISABILITIES RESEARCH REVIEWS 2000; 6:198-206. [PMID: 10982497 DOI: 10.1002/1098-2779(2000)6:3<198::aid-mrdd7>3.0.co;2-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The search for a neurobiological substrate for dyslexia has focused on anomalous planum symmetry. The results of imaging studies of the planum have been inconsistent, perhaps due to diagnostic uncertainty, technical differences in measurement criteria, and inadequate control of handedness, sex, and cognitive ability. Although structural imaging studies have not clarified the neurobiology of reading disability, converging evidence suggests that variation in asymmetry of the planum temporale does have functional significance. Studies in a variety of populations have shown a significant association between planar asymmetry, the strength of hand preference, and general verbal skills such as vocabulary and comprehension. Future structural imaging studies of dyslexia should match participants on hand preference and general verbal ability in order to determine the relationship between brain structure and written and oral language.
Collapse
Affiliation(s)
- M A Eckert
- Department of Neuroscience, University of Florida Brain Institute, Gainesville, Florida 32610, USA.
| | | |
Collapse
|
31
|
Eliez S, Rumsey JM, Giedd JN, Schmitt JE, Patwardhan AJ, Reiss AL. Morphological alteration of temporal lobe gray matter in dyslexia: an MRI study. J Child Psychol Psychiatry 2000; 41:637-44. [PMID: 10946755 DOI: 10.1111/1469-7610.00650] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Functional imaging studies of developmental dyslexia have reported reduced task-related neural activity in the temporal and inferior parietal cortices. To examine the possible contribution of subtle anatomic deviations to these reductions, volumes were measured for the major lobes of the brain, the subcortical nuclei, cerebellum, and lateral ventricles on magnetic resonance imaging (MRI) scans from 16 right-handed dyslexic men, ages 18 to 40, and 14 matched controls, most of whom had previously undergone PET imaging. A specific decrease in tissue volume was localized to the temporal lobes and was particularly prominent on the left (p < .01). An analysis of tissue composition revealed that this reduction was primarily attributable to decreased gray matter within the left temporal lobe (p < .002). Further segmentation of the temporal lobe showed that this reduction was not confined to the superior temporal gyrus, the primary location of primary auditory cortex. Reductions of temporal lobe gray matter may reflect a regional decrease in neuronal number or neuropil, which in turn may result in reading impairment.
Collapse
Affiliation(s)
- S Eliez
- Dept of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, CA 94305-5719, USA.
| | | | | | | | | | | |
Collapse
|
32
|
Abstract
Until recently, many thought developmental dyslexia was a behavioral disorder that primarily affected reading. In fact, it is a partly heritable condition, the clinical manifestations of which are extremely complex including deficits in reading, working memory, sensorimotor coordination, and early sensory processing. Even though extensive research has characterized these behavioral abnormalities carefully, the biological mechanisms of the clinical manifestations still are poorly understood. Recent research into both the nature of the structural and functional abnormalities in developmental dyslexia and the functional neuroanatomy of reading have rapidly advanced our understanding of the localization of the processes responsible for the signs and symptoms of dyslexia. This paper reviews recent evidence supporting a biological basis for developmental dyslexia.
Collapse
Affiliation(s)
- T Zeffiro
- Georgetown University Medical Center, Washington, DC 20007, USA.
| | | |
Collapse
|