Developmental dyslexia: Gray matter abnormalities in the occipitotemporal cortex

Kronbichler, Martin; Wimmer, Heinz; Staffen, Wolfgang; Hutzler, Florian; Mair, Alois; Ladurner, G.

doi:10.1002/hbm.20425

Cited by 156 publications

(147 citation statements)

References 76 publications

(168 reference statements)

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“…Differences in non-cortical regions included the hippocampus/parahippocampus, amygdala, globus pallidus and putamen. These brain regions correlate with areas identified previously as being involved in reading and/or symbol decoding either structurally or functionally (Kronbichler et al 2007;Brambati et al 2006;Cao et al 2006;Casanova et al 2005;Silani et al 2005;Vinckenbosch et al 2005;Aylward et al 2003;Eckert et al 2003;Ruff et al 2003;Brown et al 2001;Eliez et al 2000;Rumsey et al 1999). …”

Section: Discussionsupporting

confidence: 74%

“…More specifically, these studies show increases in GM volume in several cortical areas pertaining to language including: posterior, medial and inferior temporal gyri, precentral and postcentral gyri, superior and medial frontal gyri and precuneus (Kronbichler et al 2007;Silani et al 2005;Vinckenbosch et al 2005). These new data suggest that gray matter changes observed in dyslexia are not merely associated with decreases in gray matter alone and have a more complex genetic etiology.…”

Section: Discussionmentioning

confidence: 68%

“…(Thompson et al 2001). In this study, we used voxel based morphometry (VBM) data from MRI scans of healthy control subjects, to determine whether the deletion is associated with GM volume, given that previous reports suggest GM volumetric anomalies in poor readers (Brambati et al 2004;Casanova et al 2005;Kronbichler et al 2007;Silani et al 2005;Vinckenbosch et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Polymorphism of DCDC2 Reveals Differences in Cortical Morphology of Healthy Individuals—A Preliminary Voxel Based Morphometry Study

Meda

Gelernter

Gruen

et al. 2007

Brain Imaging and Behavior

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Objective-The purpose of this investigation was to determine whether there is an association between the putative reading disability (RD) susceptibility gene Doublecortin Domain Containing 2 (DCDC2), and gray matter (GM) distribution in the brain, in a sample of healthy control individuals.Method-Fifty-six control subjects were genotyped for an RD-associated deletion in intron 2 of DCDC2. Voxel based morphometry (VBM) was used to examine structural magnetic resonance imaging (MRI) scans to assess GM differences between the two groups.Results-Individuals heterozygous for the deletion exhibited significantly higher GM volumes in reading/language and symbol-decoding related brain regions including superior, medial and inferior temporal, fusiform, hippocampal/para-hippocampal, inferior occipito-parietal, inferior and middle frontal gyri, especially in the left hemisphere. GM values correlated with published data on regional DCDC2 expression in a lateralized manner.Conclusions-These data suggest a role for DCDC2 in GM distribution in language-related brain regions in healthy individuals.

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Section: Discussionsupporting

confidence: 74%

Section: Discussionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

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Polymorphism of DCDC2 Reveals Differences in Cortical Morphology of Healthy Individuals—A Preliminary Voxel Based Morphometry Study

Meda

Gelernter

Gruen

et al. 2007

Brain Imaging and Behavior

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“…Furthermore, most studies using diffusion tensor imaging (Beaulieu et al, 2005;Deutsch et al, 2005;Klingberg et al, 2000;Niogi and McCandliss, 2006) and voxelbased morphometry (VBM) (Eckert et al, 2005;Silani et al, 2005) have associated dyslexia with changes in anatomical connections of temporo-parietal regions. To date, only one VBM study found reduced gray matter density in the left inferior occipitotemporal cortex in adults and adolescents with dyslexia (Kronbichler et al, 2008). Accordingly, specifically designed studies combining techniques for examining A C C E P T E D M A N U S C R I P T…”

Section: Accepted Manuscriptmentioning

confidence: 99%

The left occipitotemporal system in reading: Disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia

et al. 2011

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The left occipitotemporal system in reading: Disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia van der Mark, S; Klaver, P; Bucher, K; Maurer, U; Schulz, E; Brem, S; Martin, E; Brandeis, D van der Mark, S; Klaver, P; Bucher, K; Maurer, U; Schulz, E; Brem, S; Martin, E; Brandeis, D (2011). The left occipitotemporal system in reading: Disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia. The left occipitotemporal system in reading: Disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia Abstract Developmental dyslexia is a severe reading disorder, which is characterized by dysfluent reading and impaired automaticity of visual word processing. Adults with dyslexia show functional deficits in several brain regions including the so-called "Visual Word Form Area" (VWFA), which is implicated in visual word processing and located within the larger left occipitotemporal VWF-System. The present study examines functional connections of the left occipitotemporal VWF-System with other major language areas in children with dyslexia. Functional connectivity MRI was used to assess connectivity of the VWF-System in 18 children with dyslexia and 24 age matched controls (age 9.7-12.5 years) using five neighbouring left occipitotemporal regions of interest (ROIs) during a continuous reading task requiring phonological and orthographic processing. First, the results revealed a focal origin of connectivity from the VWF-System, in that mainly the VWFA was functionally connected with typical left frontal and parietal language areas in control children. Adjacent posterior and anterior VWF-System ROIs did not show such connectivity, confirming the special role that the VWFA plays in word processing. Second, we detected a significant disruption of functional connectivity between the VWFA and left inferior frontal and left inferior parietal language areas in the children with dyslexia. The current findings add to our understanding of dyslexia by showing that functional disconnection of the left occipitotemporal system is limited to the small VWFA region crucial for automatic visual word processing, and emerges early during reading acquisition in children with dyslexia, along with deficits in orthographic and phonological processing of visual word forms. ÔØ Å ÒÙ× Ö ÔØThe left occipitotemporal system in reading: Disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the cont...

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“…Voxel-based morphometry reveals differences in gray-matter volume indices in individuals with DD (compared with typical reading controls) in various areas of the brain, including left occipitotemporal and temporoparietal areas (44,(56)(57)(58)(59)(60)(61), bilateral fusiform (59), and lingual gyrus (LG) (58) as well as the cerebellum (56-58). Morphological abnormalities in these regions can be identified even before reading skills are present in children as young as 5 to 6 y of age, suggesting atypical early development or even a genetic basis for DD (62).…”

mentioning

confidence: 99%

Functional characteristics of developmental dyslexia in left-hemispheric posterior brain regions predate reading onset

Raschle

Zuk²,

Gaab³

2012

Proc. Natl. Acad. Sci. U.S.A.

208

190

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Individuals with developmental dyslexia (DD) show a disruption in posterior left-hemispheric neural networks during phonological processing. Additionally, compensatory mechanisms in children and adults with DD have been located within frontal brain areas. However, it remains unclear when and how differences in posterior left-hemispheric networks manifest and whether compensatory mechanisms have already started to develop in the prereading brain. Here we investigate functional networks during phonological processing in 36 prereading children with a familial risk for DD (n = 18, average age = 66.50 mo) compared with age and IQ-matched controls (n = 18; average age = 65.61 mo). Functional neuroimaging results reveal reduced activation in prereading children with a family-history of DD (FHD + ), compared with those without (FHD − ), in bilateral occipitotemporal and left temporoparietal brain regions. This finding corresponds to previously identified hypoactivations in left hemispheric posterior brain regions for school-aged children and adults with a diagnosis of DD. Furthermore, left occipitotemporal and temporoparietal brain activity correlates positively with prereading skills in both groups. Our results suggest that differences in neural correlates of phonological processing in individuals with DD are not a result of reading failure, but are present before literacy acquisition starts. Additionally, no hyperactivation in frontal brain regions was observed, suggesting that compensatory mechanisms for reading failureare not yet present. Future longitudinal studies are needed to determine whether the identified differences may serve as neural premarkers for the early identification of children at risk for DD.is a specific learning disability that affects about 5-17% of all children (1, 2). DD is characterized by difficulties with accurate and fluent word recognition and poor spelling and decoding performance. DD cannot be accounted for by poor vision, hearing, or a lack of motivation. Molecular-genetic, twin, and family studies have shown a marked familial risk for DD, with an increasing prevalence in families with one or more members with a diagnosis of DD or reading difficulties (e.g., refs. 3 and 4). In addition, several DD susceptibility genes crucial for early brain development have been reported (5-8). DD can have severe social and psychological consequences (9-11) and may impact a child's life beyond their academic pursuits. Studies have shown that children with learning disabilities are less likely to complete high school (12) and are more likely to enter the juvenile justice system (13).Most researchers, clinicians, and reading specialists agree that DD typically results from a weakness in the ability to manipulate oral speech sounds of language (2,14). Individuals with DD are often unable to access the underlying sound structures of words, creating a difficulty in mapping sounds to written language (15-18). Phonological processing skills have been found to be a key predictor of later reading ability in pr...

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Developmental dyslexia: Gray matter abnormalities in the occipitotemporal cortex

Cited by 156 publications

References 76 publications

Polymorphism of DCDC2 Reveals Differences in Cortical Morphology of Healthy Individuals—A Preliminary Voxel Based Morphometry Study

Polymorphism of DCDC2 Reveals Differences in Cortical Morphology of Healthy Individuals—A Preliminary Voxel Based Morphometry Study

The left occipitotemporal system in reading: Disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia

Functional characteristics of developmental dyslexia in left-hemispheric posterior brain regions predate reading onset

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