Publications by authors named "Maaike Vandermosten"

37 Publications

How to capture developmental brain dynamics: gaps and solutions.

NPJ Sci Learn 2021 May 3;6(1):10. Epub 2021 May 3.

Dept. of Cognitive Neuroscience, and Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.

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http://dx.doi.org/10.1038/s41539-021-00088-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8093270PMC
May 2021

A three-time point longitudinal investigation of the arcuate fasciculus throughout reading acquisition in children developing dyslexia.

Neuroimage 2021 Apr 17:118087. Epub 2021 Apr 17.

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium; Research Group ExpORL, Department of Neurosciences, KU Leuven, Belgium; Psychological Sciences Research Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium; Institute of Neuroscience, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium. Electronic address:

Although the neural basis of dyslexia has intensively been investigated, results are still unclear about the existence of a white matter deficit in the arcuate fasciculus (AF) throughout development. To unravel this ambiguity, we examined the difference in fractional anisotropy (FA) of the AF between children developing dyslexia and children developing typical reading skills in a longitudinal sample with three MRI time points throughout reading development: the pre-reading stage (5-6 years old), the early reading stage (7-8 years old) and the advanced reading stage (9-10 years old). Applying along-the-tract analyses of white matter organization, our results confirmed that a white matter deficit existed in the left AF prior to the onset of formal reading instruction in children who developed dyslexia later on. This deficit was consistently present throughout the course of reading development. Additionally, we evaluated the use of applying a continuous approach on the participants' reading skills rather than the arbitrary categorization in individuals with or without dyslexia. Our results confirmed the predictive relation between FA and word reading measurements later in development. This study supports the use of longitudinal approaches to investigate the neural basis of the developmental process of learning to read and the application of triangulation, i.e. using multiple research approaches to help gain more insight and aiding the interpretation of obtained results.
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http://dx.doi.org/10.1016/j.neuroimage.2021.118087DOI Listing
April 2021

The relation between neurofunctional and neurostructural determinants of phonological processing in pre-readers.

Dev Cogn Neurosci 2020 12 20;46:100874. Epub 2020 Oct 20.

Research Group Experimental ORL, Department of Neurosciences, KU Leuven - University of Leuven, Herestraat 49 Box 721, B-3000 Leuven, Belgium.

Phonological processing skills are known as the most robust cognitive predictor of reading ability. Therefore, the neural determinants of phonological processing have been extensively investigated by means of either neurofunctional or neurostructural techniques. However, to fully understand how the brain represents and processes phonological information, there is need for studies that combine both methods. The present study applies such a multimodal approach with the aim of investigating the pre-reading relation between neural measures of auditory temporal processing, white matter properties of the reading network and phonological processing skills. We administered auditory steady-state responses, diffusion-weighted MRI scans and phonological awareness tasks in 59 pre-readers. Our results demonstrate that a stronger rightward lateralization of syllable-rate (4 Hz) processing coheres with higher fractional anisotropy in the left fronto-temporoparietal arcuate fasciculus. Both neural features each in turn relate to better phonological processing skills. As such, the current study provides novel evidence for the existence of a pre-reading relation between functional measures of syllable-rate processing, structural organization of the arcuate fasciculus and cognitive precursors of reading development. Moreover, our findings demonstrate the value of combining different neural techniques to gain insight in the underlying neural systems for reading (dis)ability.
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http://dx.doi.org/10.1016/j.dcn.2020.100874DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606842PMC
December 2020

Pre-literacy heterogeneity in Dutch-speaking kindergartners: latent profile analysis.

Ann Dyslexia 2020 10 19;70(3):275-294. Epub 2020 Oct 19.

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.

Research demonstrated that a dyslexia diagnosis is mainly given after the most effective time for intervention has passed, referred to as the dyslexia paradox. Although some pre-reading cognitive measures have been found to be strong predictors of early literacy acquisition, i.e., phonological awareness (PA), letter knowledge (LK), and rapid automatized naming (RAN), more insight in the variability of pre-reading profiles might be of great importance for early identification of children who have an elevated risk for developing dyslexia and to provide tailor-made interventions. To address this issue, this study used a latent profile analysis (LPA) to disentangle different pre-reading profiles in a sample of 1091 Dutch-speaking kindergartners. Four profiles emerged: high performers (16.50%), average performers (40.24%), below-average performers with average IQ (25.57%), and below-average performers with below-average IQ (17.69%). These results suggested two at-risk profiles diverging in IQ, which are presumably more likely to develop dyslexia later on. Although below-average profiles differed significantly in rapid naming and IQ, no clear evidence for the double-deficit theory was found in Dutch-speaking kindergartners. Educational level and reading history of the parents appeared to be predictive for children's classification membership. Our results point towards the heterogeneity that is already present in kindergartners and the possibility to identify at-risk profiles prior to reading instruction, which may be the foundation for earlier targeted interventions. However, more extended research is needed to determine the stability of these profiles across time and across different languages.
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http://dx.doi.org/10.1007/s11881-020-00207-9DOI Listing
October 2020

Investigating the Added Value of FreeSurfer's Manual Editing Procedure for the Study of the Reading Network in a Pediatric Population.

Front Hum Neurosci 2020 24;14:143. Epub 2020 Apr 24.

Research Group ExpORL, Department of Neuroscience, KU Leuven, Leuven, Belgium.

Insights into brain anatomy are important for the early detection of neurodevelopmental disorders, such as dyslexia. FreeSurfer is one of the most frequently applied automatized software tools to study brain morphology. However, quality control of the outcomes provided by FreeSurfer is often ignored and could lead to wrong statistical inferences. Additional manual editing of the data may be a solution, although not without a cost in time and resources. Past research in adults on comparing the automatized method of FreeSurfer with and without additional manual editing indicated that although editing may lead to significant differences in morphological measures between the methods in some regions, it does not substantially change the sensitivity to detect clinical differences. Given that automated approaches are more likely to fail in pediatric-and inherently more noisy-data, we investigated in the current study whether FreeSurfer can be applied fully automatically or additional manual edits of T1-images are needed in a pediatric sample. Specifically, cortical thickness and surface area measures with and without additional manual edits were compared in six regions of interest (ROIs) of the reading network in 5-to-6-year-old children with and without dyslexia. Results revealed that additional editing leads to statistical differences in the morphological measures, but that these differences are consistent across subjects and that the sensitivity to reveal statistical differences in the morphological measures between children with and without dyslexia is not affected, even though conclusions of marginally significant findings can differ depending on the method used. Thereby, our results indicate that additional manual editing of reading-related regions in FreeSurfer has limited gain for pediatric samples.
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http://dx.doi.org/10.3389/fnhum.2020.00143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7194167PMC
April 2020

The association of grey matter volume and cortical complexity with individual differences in children's arithmetic fluency.

Neuropsychologia 2020 02 3;137:107293. Epub 2019 Dec 3.

Parenting and Special Education Research Unit, KU Leuven, Belgium. Electronic address:

Only a small amount of studies have looked at the structural neural correlates of children's arithmetic. Furthermore, these studies mainly implemented voxel-based morphometry, which only takes the volume of regions into account, without looking at other structural properties. The current study aimed to contribute knowledge on which brain regions are important for children's arithmetic on a structural level, by not only implementing voxel-based morphometry, but also cortical complexity analyses, based on the fractal dimension index. This complexity measure describes a characteristic of surface shape. Data of 43 typically developing 9-10 year-olds were analyzed. All children were asked to take part in two test sessions: behavioral data collection and MRI data acquisition. For data analysis, mean values for volume and cortical complexity were estimated within regions of interest (ROIs) and extracted for further analysis. The selected ROIs were based on regions found to be related to children's mathematical abilities in previous research. Results point towards associations between arithmetic fluency and the volume of the right fusiform gyrus, as well as the cortical complexity of the left postcentral gyrus, right insular sulcus, and left lateral orbital sulcus. Remarkably, no significant associations were observed between the children's arithmetic fluency and the volume or cortical complexity of typically arithmetic-associated parietal regions, such as the superior parietal lobe, intraparietal sulcus, or angular gyrus. Accordingly, the current study highlights the importance of structural characteristics of brain regions other than these typically arithmetic-associated parietal regions for children's arithmetic fluency.
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http://dx.doi.org/10.1016/j.neuropsychologia.2019.107293DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7000239PMC
February 2020

Atypical gray matter in children with dyslexia before the onset of reading instruction.

Cortex 2019 12 11;121:399-413. Epub 2019 Oct 11.

Parenting & Special Education Research Unit, Faculty of Psychology & Educational Sciences, KU Leuven, Belgium.

Many studies have focused on neuroanatomical anomalies in dyslexia, yet primarily in school-aged children and adults. In the present study, we investigated gray matter surface area and cortical thickness at the pre-reading stage in a cohort of 54 children, 31 with a family risk for dyslexia and 23 without a family risk for dyslexia, of whom 16 children developed dyslexia. Surface-based analyses in the core regions of the reading network in the left hemisphere and in the corresponding right hemispheric regions were performed in FreeSurfer. Results revealed that pre-readers who develop dyslexia show reduced surface area in bilateral fusiform gyri. In addition, anomalies related to a family risk for dyslexia, irrespectively of later reading ability, were observed in the area of the bilateral inferior and middle temporal gyri. Differences were apparent in surface area, as opposed to cortical thickness. Results indicate that the neuroanatomical anomalies, since they are observed in the pre-reading phase, are not the consequence of impoverished reading experience.
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http://dx.doi.org/10.1016/j.cortex.2019.09.010DOI Listing
December 2019

Brain activity patterns of phonemic representations are atypical in beginning readers with family risk for dyslexia.

Dev Sci 2020 01 21;23(1):e12857. Epub 2019 Jun 21.

Department of Cognitive Neuroscience and Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.

There is an ongoing debate whether phonological deficits in dyslexics should be attributed to (a) less specified representations of speech sounds, like suggested by studies in young children with a familial risk for dyslexia, or (b) to an impaired access to these phonemic representations, as suggested by studies in adults with dyslexia. These conflicting findings are rooted in between study differences in sample characteristics and/or testing techniques. The current study uses the same multivariate functional MRI (fMRI) approach as previously used in adults with dyslexia to investigate phonemic representations in 30 beginning readers with a familial risk and 24 beginning readers without a familial risk of dyslexia, of whom 20 were later retrospectively classified as dyslexic. Based on fMRI response patterns evoked by listening to different utterances of /bA/ and /dA/ sounds, multivoxel analyses indicate that the underlying activation patterns of the two phonemes were distinct in children with a low family risk but not in children with high family risk. However, no group differences were observed between children that were later classified as typical versus dyslexic readers, regardless of their family risk status, indicating that poor phonemic representations constitute a risk for dyslexia but are not sufficient to result in reading problems. We hypothesize that poor phonemic representations are trait (family risk) and not state (dyslexia) dependent, and that representational deficits only lead to reading difficulties when they are present in conjunction with other neuroanatomical or-functional deficits.
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http://dx.doi.org/10.1111/desc.12857DOI Listing
January 2020

The neural substrates of the problem size and interference effect in children's multiplication: An fMRI study.

Brain Res 2019 07 2;1714:147-157. Epub 2019 Mar 2.

Parenting and Special Education Research Unit, KU Leuven, Leopold Vanderkelenstraat 32, Box 3765, 3000 Leuven, Belgium.

Within children's multiplication fact retrieval, performance can be influenced by various effects, such as the well-known problem size effect (i.e., smaller problems are solved faster and more accurately) and the more recent interference effect (i.e., the quality of memory representations of problems depends on previously learned problems; the more similar a problem is to a previously learned one, the more proactive interference impacts on storing in long-term-memory). This interference effect has been observed in behavioral studies, and determines a substantial part of performance beyond problem size. Unlike the problem size effect, the neural basis of the interference effect in children has not been studied. To better understand the underpinning mechanisms behind children's arithmetic fact retrieval, we aimed to investigate the neural basis of both effects in typically developing children. Twenty-four healthy 9- to 10-year-olds took part in a behavioral and fMRI scanning session, during which multiplication items had to be solved. Data were analyzed by manipulating problem size and interference level in a 2 × 2 factorial design. Concurring with previous studies, our results reveal clear behavioral effects of problem size and interference, with larger and high interfering items being solved significantly slower. On the neural level, a clear problem size effect was observed in a fronto-parietal and temporal network. The interference effect, however, was not detected; no clear neural distinctions were observed between low and high interfering items.
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http://dx.doi.org/10.1016/j.brainres.2019.03.002DOI Listing
July 2019

Corrigendum to "A qualitative and quantitative review of diffusion tensor imaging studies in reading and dyslexia" [Neurosci. Biobehav. Rev. 36 (2012), 1532-1552].

Neurosci Biobehav Rev 2019 03 12;98:334. Epub 2019 Jan 12.

Parenting and Special Education Research Unit, KU Leuven, L. Vanderkelenstraat 32, 3000, Leuven, Belgium.

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http://dx.doi.org/10.1016/j.neubiorev.2018.12.019DOI Listing
March 2019

Relating individual differences in white matter pathways to children's arithmetic fluency: a spherical deconvolution study.

Brain Struct Funct 2019 Jan 13;224(1):337-350. Epub 2018 Oct 13.

Parenting and Special Education Research Unit, KU Leuven, Leopold Vanderkelenstraat 32, box 3765, 3000, Leuven, Belgium.

Connectivity between brain regions is integral to efficient complex cognitive processing, making the study of white matter pathways in clarifying the neural mechanisms of individual differences in arithmetic abilities critical. This white matter connectivity underlying arithmetic has only been investigated through classic diffusion tensor imaging, which, due to methodological limitations, might lead to an oversimplification of the underlying anatomy. More complex non-tensor models, such as spherical deconvolution, however, allow a much more fine-grained delineation of the underlying brain anatomy. Against this background, the current study is the first to use spherical deconvolution to investigate white matter tracts and their relation to individual differences in arithmetic fluency in typically developing children. Participants were 48 typically developing 9-10-year-olds, who were all in grade 4, and who underwent structural diffusion-weighted magnetic resonance imaging scanning. Theoretically relevant white matter tracts were manually delineated with a region of interest approach, after which the hindrance modulated orientational anisotropy (HMOA) index, which provides information on the structural integrity of the tract at hand, was derived for each tract. These HMOA indices were correlated with measures of arithmetic fluency, using frequentist and Bayesian approaches. Our results point towards an association between the HMOA of the right inferior longitudinal fasciculus and individual differences in arithmetic fluency. This might reflect the efficiency with which children process Arabic numerals. Other previously found associations between white matter and individual differences in arithmetic fluency were not observed.
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http://dx.doi.org/10.1007/s00429-018-1770-6DOI Listing
January 2019

Grapheme-Phoneme Learning in an Unknown Orthography: A Study in Typical Reading and Dyslexic Children.

Front Psychol 2018 15;9:1393. Epub 2018 Aug 15.

Laboratory for Experimental ORL, KU Leuven, Leuven, Belgium.

In this study, we examined the learning of new grapheme-phoneme correspondences in individuals with and without dyslexia. Additionally, we investigated the relation between grapheme-phoneme learning and measures of phonological awareness, orthographic knowledge and rapid automatized naming, with a focus on the unique joint variance of grapheme-phoneme learning to word and non-word reading achievement. Training of grapheme-phoneme associations consisted of a 20-min training program in which eight novel letters (Hebrew) needed to be paired with speech sounds taken from the participant's native language (Dutch). Eighty-four third grade students, of whom 20 were diagnosed with dyslexia, participated in the training and testing. Our results indicate a reduced ability of dyslexic readers in applying newly learned grapheme-phoneme correspondences while reading words which consist of these novel letters. However, we did not observe a significant independent contribution of grapheme-phoneme learning to reading outcomes. Alternatively, results from the regression analysis indicate that failure to read may be due to differences in phonological and/or orthographic knowledge but not to differences in the grapheme-phoneme-conversion process itself.
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http://dx.doi.org/10.3389/fpsyg.2018.01393DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6103482PMC
August 2018

Evaluation of methods for volumetric analysis of pediatric brain data: The child pipeline versus adult-based approaches.

Neuroimage Clin 2018 23;19:734-744. Epub 2018 May 23.

Experimental Oto-rhino-laryngology, Department Neurosciences, KU Leuven, Leuven, Belgium.

Pediatric brain volumetric analysis based on Magnetic Resonance Imaging (MRI) is of particular interest in order to understand the typical brain development and to characterize neurodevelopmental disorders at an early age. However, it has been shown that the results can be biased due to head motion, inherent to pediatric data, and due to the use of methods based on adult brain data that are not able to accurately model the anatomical disparity of pediatric brains. To overcome these issues, we proposed child, a tool developed for the analysis of pediatric neuroimaging data that uses an age-specific atlas and a probabilistic model-based approach in order to segment the gray matter (GM) and white matter (WM). The tool was extensively validated on 55 scans of children between 5 and 6 years old (including 13 children with developmental dyslexia) and 10 pairs of test-retest scans of children between 6 and 8 years old and compared with two state-of-the-art methods using an adult atlas, namely ico (applying a probabilistic model-based segmentation) and Freesurfer (applying a surface model-based segmentation). The results obtained with child showed a better reproducibility of GM and WM segmentations and a better robustness to head motion in the estimation of GM volume compared to Freesurfer. Evaluated on two subjects, child showed good accuracy with 82-84% overlap with manual segmentation for both GM and WM, thereby outperforming the adult-based methods (icobrain and Freesurfer), especially for the subject with poor quality data. We also demonstrated that the adult-based methods needed double the number of subjects to detect significant morphological differences between dyslexics and typical readers. Once further developed and validated, we believe that child would provide appropriate and reliable measures for the examination of children's brain.
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http://dx.doi.org/10.1016/j.nicl.2018.05.030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6040578PMC
January 2019

Neural organization of ventral white matter tracts parallels the initial steps of reading development: A DTI tractography study.

Brain Lang 2018 08 18;183:32-40. Epub 2018 May 18.

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium.

Insight in the developmental trajectory of the neuroanatomical reading correlates is important to understand related cognitive processes and disorders. In adults, a dual pathway model has been suggested encompassing a dorsal phonological and a ventral orthographic white matter system. This dichotomy seems not present in pre-readers, and the specific role of ventral white matter in reading remains unclear. Therefore, the present longitudinal study investigated the relation between ventral white matter and cognitive processes underlying reading in children with a broad range of reading skills (n = 61). Ventral pathways of the reading network were manually traced using diffusion tractography: the inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF) and uncinate fasciculus (UF). Pathways were examined pre-reading (5-6 years) and after two years of reading acquisition (7-8 years). Dimension reduction for the cognitive measures resulted in one component for pre-reading cognitive measures and a separate phonological and orthographic component for the early reading measures. Regression analyses revealed a relation between the pre-reading cognitive component and bilateral IFOF and left ILF. Interestingly, exclusively the left IFOF was related to the orthographic component, whereas none of the pathways was related to the phonological component. Hence, the left IFOF seems to serve as the lexical reading route, already in the earliest reading stages.
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http://dx.doi.org/10.1016/j.bandl.2018.05.007DOI Listing
August 2018

Atypical Structural Asymmetry of the Planum Temporale is Related to Family History of Dyslexia.

Cereb Cortex 2018 01;28(1):63-72

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.

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.
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http://dx.doi.org/10.1093/cercor/bhw348DOI Listing
January 2018

Processing of structural neuroimaging data in young children: Bridging the gap between current practice and state-of-the-art methods.

Dev Cogn Neurosci 2018 10 24;33:206-223. Epub 2017 Aug 24.

Experimental Oto-rhino-laryngology, Department Neurosciences, KU Leuven, Leuven, Belgium.

The structure of the brain is subject to very rapid developmental changes during early childhood. Pediatric studies based on Magnetic Resonance Imaging (MRI) over this age range have recently become more frequent, with the advantage of providing in vivo and non-invasive high-resolution images of the developing brain, toward understanding typical and atypical trajectories. However, it has also been demonstrated that application of currently standard MRI processing methods that have been developed with datasets from adults may not be appropriate for use with pediatric datasets. In this review, we examine the approaches currently used in MRI studies involving young children, including an overview of the rationale for new MRI processing methods that have been designed specifically for pediatric investigations. These methods are mainly related to the use of age-specific or 4D brain atlases, improved methods for quantifying and optimizing image quality, and provision for registration of developmental data obtained with longitudinal designs. The overall goal is to raise awareness of the existence of these methods and the possibilities for implementing them in developmental neuroimaging studies.
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http://dx.doi.org/10.1016/j.dcn.2017.08.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969273PMC
October 2018

Early dynamics of white matter deficits in children developing dyslexia.

Dev Cogn Neurosci 2017 10 8;27:69-77. Epub 2017 Aug 8.

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium.

Neural anomalies have been demonstrated in dyslexia. Recent studies in pre-readers at risk for dyslexia and in pre-readers developing poor reading suggest that these anomalies might be a cause of their reading impairment. Our study goes one step further by exploring the neurodevelopmental trajectory of white matter anomalies in pre-readers with and without a familial risk for dyslexia (n=61) of whom a strictly selected sample develops dyslexia later on (n=15). We collected longitudinal diffusion MRI and behavioural data until grade 3. The results provide evidence that children with dyslexia exhibit pre-reading white matter anomalies in left and right long segment of the arcuate fasciculus (AF), with predictive power of the left segment above traditional cognitive measures and familial risk. Whereas white matter differences in the left AF seem most strongly related to the development of dyslexia, differences in the left IFOF and in the right AF seem driven by both familial risk and later reading ability. Moreover, differences in the left AF appeared to be dynamic. This study supports and expands recent insights into the neural basis of dyslexia, pointing towards pre-reading anomalies related to dyslexia, as well as underpinning the dynamic character of white matter.
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http://dx.doi.org/10.1016/j.dcn.2017.08.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6987857PMC
October 2017

Strategy over operation: neural activation in subtraction and multiplication during fact retrieval and procedural strategy use in children.

Hum Brain Mapp 2017 09 19;38(9):4657-4670. Epub 2017 Jun 19.

Parenting and Special Education Research Unit, KU Leuven, Leuven, Belgium.

Arithmetic development is characterized by strategy shifts between procedural strategy use and fact retrieval. This study is the first to explicitly investigate children's neural activation associated with the use of these different strategies. Participants were 26 typically developing 4th graders (9- to 10-year-olds), who, in a behavioral session, were asked to verbally report on a trial-by-trial basis how they had solved 100 subtraction and multiplication items. These items were subsequently presented during functional magnetic resonance imaging. An event-related design allowed us to analyze the brain responses during retrieval and procedural trials, based on the children's verbal reports. During procedural strategy use, and more specifically for the decomposition of operands strategy, activation increases were observed in the inferior and superior parietal lobes (intraparietal sulci), inferior to superior frontal gyri, bilateral areas in the occipital lobe, and insular cortex. For retrieval, in comparison to procedural strategy use, we observed increased activity in the bilateral angular and supramarginal gyri, left middle to inferior temporal gyrus, right superior temporal gyrus, and superior medial frontal gyrus. No neural differences were found between the two operations under study. These results are the first in children to provide direct evidence for alternate neural activation when different arithmetic strategies are used and further unravel that previously found effects of operation on brain activity reflect differences in arithmetic strategy use. Hum Brain Mapp 38:4657-4670, 2017. © 2017 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/hbm.23691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6866817PMC
September 2017

White matter pathways mediate parental effects on children's reading precursors.

Brain Lang 2017 10 27;173:10-19. Epub 2017 May 27.

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium.

Previous studies have shown that the link between parental and offspring's reading is mediated by the cognitive system of the offspring, yet information about the mediating role of the neurobiological system is missing. This family study includes cognitive and diffusion MRI (dMRI) data collected in 71 pre-readers as well as parental reading and environmental data. Using sequential path analyses, which take into account the interrelationships between the different components, we observed mediating effects of the neurobiological system. More specifically, fathers' reading skills predicted reading of the child by operating through a child's left ventral white matter pathway. For mothers no clear mediating role of the neural system was observed. Given that our study involves children who have not yet learned to read and that environmental measures were taken into account, the paternal effect on a child's white matter pathway is unlikely to be only driven by environmental factors. Future intergenerational studies focusing on the genetic, neurobiological and cognitive level of parents and offspring will provide more insight in the relative contribution of parental environment and genes.
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http://dx.doi.org/10.1016/j.bandl.2017.05.002DOI Listing
October 2017

Predicting Future Reading Problems Based on Pre-reading Auditory Measures: A Longitudinal Study of Children with a Familial Risk of Dyslexia.

Front Psychol 2017 7;8:124. Epub 2017 Feb 7.

Laboratory for Experimental ORL, Department of Neuroscience, KU Leuven Leuven, Belgium.

This longitudinal study examines measures of temporal auditory processing in pre-reading children with a family risk of dyslexia. Specifically, it attempts to ascertain whether pre-reading auditory processing, speech perception, and phonological awareness (PA) reliably predict later literacy achievement. Additionally, this study retrospectively examines the presence of pre-reading auditory processing, speech perception, and PA impairments in children later found to be literacy impaired. Forty-four pre-reading children with and without a family risk of dyslexia were assessed at three time points (kindergarten, first, and second grade). Auditory processing measures of rise time (RT) discrimination and frequency modulation (FM) along with speech perception, PA, and various literacy tasks were assessed. Kindergarten RT uniquely contributed to growth in literacy in grades one and two, even after controlling for letter knowledge and PA. Highly significant concurrent and predictive correlations were observed with kindergarten RT significantly predicting first grade PA. Retrospective analysis demonstrated atypical performance in RT and PA at all three time points in children who later developed literacy impairments. Although significant, kindergarten auditory processing contributions to later literacy growth lack the power to be considered as a single-cause predictor; thus results support temporal processing deficits' contribution within a multiple deficit model of dyslexia.
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http://dx.doi.org/10.3389/fpsyg.2017.00124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5293743PMC
February 2017

Integrating MRI brain imaging studies of pre-reading children with current theories of developmental dyslexia: A review and quantitative meta-analysis.

Curr Opin Behav Sci 2016 Aug;10:155-161

Northwestern University, Roxelyn & Richard Pepper Department of Communication Sciences and Disorders, 2240 Campus Dr., Evanston IL 60208, USA.

The neurobiological substrates that cause people with dyslexia to experience difficulty in acquiring accurate and fluent reading skills are still largely unknown. Although structural and functional brain anomalies associated with dyslexia have been reported in adults and school-age children, these anomalies may represent differences in reading experience rather than the etiology of dyslexia. Conducting MRI studies of pre-readers at risk for dyslexia is one approach that enables us to identify brain alterations that exist before differences in reading experience emerge. The current review summarizes MRI studies that examine brain differences associated with risk for dyslexia in children before reading instruction and meta-analyzes these studies. In order to link these findings with current etiological theories of dyslexia, we focus on studies that take a modular perspective rather than a network approach. Although some of the observed differences in pre-readers at risk for dyslexia may still be shaped by language experiences during the first years of life, such studies underscore the existence of reading-related brain anomalies prior to reading onset and could eventually lead to earlier and more precise diagnosis and treatment of dyslexia.
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http://dx.doi.org/10.1016/j.cobeha.2016.06.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4957935PMC
August 2016

Plasticity of white matter connectivity in phonetics experts.

Brain Struct Funct 2016 09 19;221(7):3825-33. Epub 2015 Sep 19.

Brain and Language Lab, Department of Clinical Neuroscience, Campus Biotech, University of Geneva, 9 Chemin des Mines, 1202, Geneva, Switzerland.

Phonetics experts are highly trained to analyze and transcribe speech, both with respect to faster changing, phonetic features, and to more slowly changing, prosodic features. Previously we reported that, compared to non-phoneticians, phoneticians had greater local brain volume in bilateral auditory cortices and the left pars opercularis of Broca's area, with training-related differences in the grey-matter volume of the left pars opercularis in the phoneticians group (Golestani et al. 2011). In the present study, we used diffusion MRI to examine white matter microstructure, indexed by fractional anisotropy, in (1) the long segment of arcuate fasciculus (AF_long), which is a well-known language tract that connects Broca's area, including left pars opercularis, to the temporal cortex, and in (2) the fibers arising from the auditory cortices. Most of these auditory fibers belong to three validated language tracts, namely to the AF_long, the posterior segment of the arcuate fasciculus and the middle longitudinal fasciculus. We found training-related differences in phoneticians in left AF_long, as well as group differences relative to non-experts in the auditory fibers (including the auditory fibers belonging to the left AF_long). Taken together, the results of both studies suggest that grey matter structural plasticity arising from phonetic transcription training in Broca's area is accompanied by changes to the white matter fibers connecting this very region to the temporal cortex. Our findings suggest expertise-related changes in white matter fibers connecting fronto-temporal functional hubs that are important for phonetic processing. Further studies can pursue this hypothesis by examining the dynamics of these expertise related grey and white matter changes as they arise during phonetic training.
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http://dx.doi.org/10.1007/s00429-015-1114-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009160PMC
September 2016

A DTI tractography study in pre-readers at risk for dyslexia.

Dev Cogn Neurosci 2015 Aug 27;14:8-15. Epub 2015 May 27.

Parenting and Special Education Research Unit, KU Leuven, L. Vanderkelenstraat 32, PO Box 3765, 3000 Leuven, Belgium.

In adults and school-aged children, phonological aspects of reading seem to be sustained by left dorsal regions, while ventral regions seem to be involved in orthographic word recognition. Yet, given that the brain reorganises during reading acquisition, it is unknown when and how these reading routes emerge and whether neural deficits in dyslexia predate reading onset. Using diffusion MRI in 36 pre-readers with a family risk for dyslexia (FRD(+)) and 35 well matched pre-readers without a family risk (FRD(-)), our results show that phonological predictors of reading are sustained bilaterally by both ventral and dorsal tracts. This suggests that a dorsal and left-hemispheric specialisation for phonological aspects of reading, as observed in adults, is presumably gradually formed throughout reading development. Second, our results indicate that FRD(+) pre-readers display mainly white matter differences in left ventral tracts. This suggests that atypical white matter organisation previously found in dyslexic adults may be causal rather than resulting from a lifetime of reading difficulties, and that the location of such a deficit may vary throughout development. While this study forms an important starting point, longitudinal follow-up of these children will allow further investigation of the dynamics between emerging literacy development and white matter connections.
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http://dx.doi.org/10.1016/j.dcn.2015.05.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6989819PMC
August 2015

Disentangling the relation between left temporoparietal white matter and reading: A spherical deconvolution tractography study.

Hum Brain Mapp 2015 Aug 3;36(8):3273-87. Epub 2015 Jun 3.

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.

Diffusion tensor imaging (DTI) studies have shown that left temporoparietal white matter is related to phonological aspects of reading. However, DTI lacks the sensitivity to disentangle whether phonological processing is sustained by intrahemispheric connections, interhemispheric connections, or projection tracts. Spherical deconvolution (SD) is a nontensor model which enables a more accurate estimation of multiple fiber directions in crossing fiber regions. Hence, this study is the first to investigate whether the observed relation with reading aspects in left temporoparietal white matter is sustained by a particular pathway by applying a nontensor model. Second, measures of degree of diffusion anisotropy, which indirectly informs about white matter organization, were compared between DTI and SD tractography. In this study, 71 children (5-6 years old) participated. Intrahemispheric, interhemispheric, and projection pathways were delineated using DTI and SD tractography. Anisotropy indices were extracted, that is, fractional anisotropy (FA) in DTI and quantitative hindrance modulated orientational anisotropy (HMOA) in SD. DTI results show that diffusion anisotropy in both the intrahemispheric and projection tracts was positively correlated to phonological awareness; however, the effect was confounded by subjects' motion. In SD, the relation was restricted to the left intrahemispheric connections. A model comparison suggested that FA was, relatively to HMOA, more confounded by fiber crossings; however, anisotropy indices were highly related. In sum, this study shows the potential of SD to quantify white matter microstructure in regions containing crossing fibers. More specifically, SD analyses show that phonological awareness is sustained by left intrahemispheric connections and not interhemispheric or projection tracts.
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http://dx.doi.org/10.1002/hbm.22848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6869773PMC
August 2015

White matter morphometric changes uniquely predict children's reading acquisition.

Psychol Sci 2014 Oct 11;25(10):1870-83. Epub 2014 Sep 11.

Division of Child and Adolescent Psychiatry, Department of Psychiatry, University of California, San Francisco Haskins Laboratories, Yale University Department of Neuropsychiatry, Keio University School of Medicine

This study examined whether variations in brain development between kindergarten and Grade 3 predicted individual differences in reading ability at Grade 3. Structural MRI measurements indicated that increases in the volume of two left temporo-parietal white matter clusters are unique predictors of reading outcomes above and beyond family history, socioeconomic status, and cognitive and preliteracy measures at baseline. Using diffusion MRI, we identified the left arcuate fasciculus and superior corona radiata as key fibers within the two clusters. Bias-free regression analyses using regions of interest from prior literature revealed that volume changes in temporo-parietal white matter, together with preliteracy measures, predicted 56% of the variance in reading outcomes. Our findings demonstrate the important contribution of developmental differences in areas of left dorsal white matter, often implicated in phonological processing, as a sensitive early biomarker for later reading abilities, and by extension, reading difficulties.
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http://dx.doi.org/10.1177/0956797614544511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4326021PMC
October 2014

The relationship of phonological ability, speech perception, and auditory perception in adults with dyslexia.

Front Hum Neurosci 2014 2;8:482. Epub 2014 Jul 2.

Laboratory for Experimental ORL, Department of Neuroscience, KU Leuven Leuven, Belgium.

This study investigated whether auditory, speech perception, and phonological skills are tightly interrelated or independently contributing to reading. We assessed each of these three skills in 36 adults with a past diagnosis of dyslexia and 54 matched normal reading adults. Phonological skills were tested by the typical threefold tasks, i.e., rapid automatic naming, verbal short-term memory and phonological awareness. Dynamic auditory processing skills were assessed by means of a frequency modulation (FM) and an amplitude rise time (RT); an intensity discrimination task (ID) was included as a non-dynamic control task. Speech perception was assessed by means of sentences and words-in-noise tasks. Group analyses revealed significant group differences in auditory tasks (i.e., RT and ID) and in phonological processing measures, yet no differences were found for speech perception. In addition, performance on RT discrimination correlated with reading but this relation was mediated by phonological processing and not by speech-in-noise. Finally, inspection of the individual scores revealed that the dyslexic readers showed an increased proportion of deviant subjects on the slow-dynamic auditory and phonological tasks, yet each individual dyslexic reader does not display a clear pattern of deficiencies across the processing skills. Although our results support phonological and slow-rate dynamic auditory deficits which relate to literacy, they suggest that at the individual level, problems in reading and writing cannot be explained by the cascading auditory theory. Instead, dyslexic adults seem to vary considerably in the extent to which each of the auditory and phonological factors are expressed and interact with environmental and higher-order cognitive influences.
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http://dx.doi.org/10.3389/fnhum.2014.00482DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4078926PMC
July 2014

Intact but less accessible phonetic representations in adults with dyslexia.

Science 2013 Dec;342(6163):1251-4

Child and Adolescent Psychiatry, KU Leuven, 3000 Leuven, Belgium.

Dyslexia is a severe and persistent reading and spelling disorder caused by impairment in the ability to manipulate speech sounds. We combined functional magnetic resonance brain imaging with multivoxel pattern analysis and functional and structural connectivity analysis in an effort to disentangle whether dyslexics' phonological deficits are caused by poor quality of the phonetic representations or by difficulties in accessing intact phonetic representations. We found that phonetic representations are hosted bilaterally in primary and secondary auditory cortices and that their neural quality (in terms of robustness and distinctness) is intact in adults with dyslexia. However, the functional and structural connectivity between the bilateral auditory cortices and the left inferior frontal gyrus (a region involved in higher-level phonological processing) is significantly hampered in dyslexics, suggesting deficient access to otherwise intact phonetic representations.
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http://dx.doi.org/10.1126/science.1244333DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3932003PMC
December 2013

White matter lateralization and interhemispheric coherence to auditory modulations in normal reading and dyslexic adults.

Neuropsychologia 2013 Sep 18;51(11):2087-99. Epub 2013 Jul 18.

ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium; Parenting and Special Education Research Unit, KU Leuven, Leopold Vanderkelenstraat 32, PO Box 3765, 3000 Leuven, Belgium; Radiology Section, KU Leuven, Herestraat 49, 3000 Leuven, Belgium. Electronic address:

Neural activation of slow acoustic variations that are important for syllable identification is more lateralized to the right hemisphere than activation of fast acoustic changes that are important for phoneme identification. It has been suggested that this complementary function at different hemispheres is rooted in a different degree of white matter myelination in the left versus right hemisphere. The present study will investigate this structure-function relationship with Diffusion Tensor Imaging (DTI) and Auditory Steady-State Responses (ASSR), respectively. With DTI we examined white matter lateralization in the cortical auditory and language regions (i.e. posterior region of the superior temporal gyrus and the arcuate fasciculus) and white matter integrity in the splenium of the corpus callosum. With ASSR we examined interhemispheric coherence to slow, syllabic-rate (i.e. 4 Hz) and fast, phonemic-rate (i.e. 20 Hz) modulations. These structural and functional techniques were applied in a group of normal reading adults and a group of dyslexic adults for whom previously reduced functional interhemispheric connectivity at 20 Hz has been reported (Poelmans et al. (2012). Ear and Hearing, 33, 134-143). This sample was chosen since it is hypothesized that in dyslexic readers insufficient hemispheric asymmetry in myelination might relate to their auditory and phonological problems. Results demonstrate reduced white matter lateralization in the posterior superior temporal gyrus and the arcuate fasciculus in the dyslexic readers. Additionally, white matter lateralization in the posterior superior temporal gyrus and white matter integrity in the splenium of the corpus callosum related to interhemispheric coherence to phonemic-rate modulations (i.e. 20 Hz). Interestingly, this correlation pattern was opposite in normal versus dyslexic readers. These results might imply that less pronounced left white matter dominance in dyslexic adults might relate to their problems to process phonemic-rate acoustic information and to integrate them into the phonological system.
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http://dx.doi.org/10.1016/j.neuropsychologia.2013.07.008DOI Listing
September 2013

Hemispheric asymmetry of auditory steady-state responses to monaural and diotic stimulation.

J Assoc Res Otolaryngol 2012 Dec 28;13(6):867-76. Epub 2012 Aug 28.

ExpORL, Department of Neurosciences, Katholieke Universiteit Leuven, Herestraat 49, PO Box 721, 3000 Leuven, Belgium.

Amplitude modulations in the speech envelope are crucial elements for speech perception. These modulations comprise the processing rate at which syllabic (~3-7 Hz), and phonemic transitions occur in speech. Theories about speech perception hypothesize that each hemisphere in the auditory cortex is specialized in analyzing modulations at different timescales, and that phonemic-rate modulations of the speech envelope lateralize to the left hemisphere, whereas right lateralization occurs for slow, syllabic-rate modulations. In the present study, neural processing of phonemic- and syllabic-rate modulations was investigated with auditory steady-state responses (ASSRs). ASSRs to speech-weighted noise stimuli, amplitude modulated at 4, 20, and 80 Hz, were recorded in 30 normal-hearing adults. The 80 Hz ASSR is primarily generated by the brainstem, whereas 20 and 4 Hz ASSRs are mainly cortically evoked and relate to speech perception. Stimuli were presented diotically (same signal to both ears) and monaurally (one signal to the left or right ear). For 80 Hz, diotic ASSRs were larger than monaural responses. This binaural advantage decreased with decreasing modulation frequency. For 20 Hz, diotic ASSRs were equal to monaural responses, while for 4 Hz, diotic responses were smaller than monaural responses. Comparison of left and right ear stimulation demonstrated that, with decreasing modulation rate, a gradual change from ipsilateral to right lateralization occurred. Together, these results (1) suggest that ASSR enhancement to binaural stimulation decreases in the ascending auditory system and (2) indicate that right lateralization is more prominent for low-frequency ASSRs. These findings may have important consequences for electrode placement in clinical settings, as well as for the understanding of low-frequency ASSR generation.
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http://dx.doi.org/10.1007/s10162-012-0348-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3505592PMC
December 2012

A qualitative and quantitative review of diffusion tensor imaging studies in reading and dyslexia.

Neurosci Biobehav Rev 2012 Jul 17;36(6):1532-52. Epub 2012 Apr 17.

Parenting and Special Education Research Unit, KU Leuven, L. Vanderkelenstraat 32, 3000 Leuven, Belgium.

In this review paper we address whether deficits in reading (i.e. developmental dyslexia) are rooted in neurobiological anomalies in white matter tracts. Diffusion tensor imaging (DTI) offers an index of the connections between brain regions (via tractography) and of the white matter properties of these connections (via fractional anisotropy, FA). The reported studies generally show that lower FA values in left temporoparietal and frontal areas are indicative of poorer reading ability or dyslexia. Second, most studies have indicated that these regions coincide with the left arcuate fasciculus and corona radiata, with fewer studies suggesting a role for the posterior part of the corpus callosum or for more ventral tracts such as the inferior longitudinal fasciculus or the inferior fronto-occipital fasciculus. Finally, a quantitative activation likelihood estimation (ALE) meta-analysis on all reported studies that used a voxel-based approach reveals a cluster located close to the left temporoparietal region (x=-29, y=-17, z=26). Fibertracking through this cluster demonstrates that this region hosts both the left arcuate fasciculus and the left corona radiata.
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http://dx.doi.org/10.1016/j.neubiorev.2012.04.002DOI Listing
July 2012