Publications by authors named "Pol Ghesquière"

86 Publications

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

A Bridge over Troubled Listening: Improving Speech-in-Noise Perception by Children with Dyslexia.

J Assoc Res Otolaryngol 2021 Apr 16. Epub 2021 Apr 16.

Department of Neurosciences, Research Group Experimental ORL, KU Leuven University of Leuven, Leuven, Belgium.

Developmental dyslexia is most commonly associated with phonological processing difficulties. However, children with dyslexia may experience poor speech-in-noise perception as well. Although there is an ongoing debate whether a speech perception deficit is inherent to dyslexia or acts as an aggravating risk factor compromising learning to read indirectly, improving speech perception might boost reading-related skills and reading acquisition. In the current study, we evaluated advanced speech technology as applied in auditory prostheses, to promote and eventually normalize speech perception of school-aged children with dyslexia, i.e., envelope enhancement (EE). The EE strategy automatically detects and emphasizes onset cues and consequently reinforces the temporal structure of the speech envelope. Our results confirmed speech-in-noise perception difficulties by children with dyslexia. However, we found that exaggerating temporal "landmarks" of the speech envelope (i.e., amplitude rise time and modulations)-by using EE-passively and instantaneously improved speech perception in noise for children with dyslexia. Moreover, the benefit derived from EE was large enough to completely bridge the initial gap between children with dyslexia and their typical reading peers. Taken together, the beneficial outcome of EE suggests an important contribution of the temporal structure of the envelope to speech perception in noise difficulties in dyslexia, providing an interesting foundation for future intervention studies based on auditory and speech rhythm training.
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http://dx.doi.org/10.1007/s10162-021-00793-4DOI 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

Subcortical auditory neural synchronization is deficient in pre-reading children who develop dyslexia.

Dev Sci 2020 11 23;23(6):e12945. Epub 2020 Apr 23.

Department of Neurosciences, Research Group Experimental ORL, KU Leuven - University of Leuven, Leuven, Belgium.

Auditory processing of temporal information in speech is sustained by synchronized firing of neurons along the entire auditory pathway. In school-aged children and adults with dyslexia, neural synchronization deficits have been found at cortical levels of the auditory system, however, these deficits do not appear to be present in pre-reading children. An alternative role for subcortical synchronization in reading development and dyslexia has been suggested, but remains debated. By means of a longitudinal study, we assessed cognitive reading-related skills and subcortical auditory steady-state responses (80 Hz ASSRs) in a group of children before formal reading instruction (pre-reading), after 1 year of formal reading instruction (beginning reading), and after 3 years of formal reading instruction (more advanced reading). Children were retrospectively classified into three groups based on family risk and literacy achievement: typically developing children without a family risk for dyslexia, typically developing children with a family risk for dyslexia, and children who developed dyslexia. Our results reveal that children who developed dyslexia demonstrate decreased 80 Hz ASSRs at the pre-reading stage. This effect is no longer present after the onset of reading instruction, due to an atypical developmental increase in 80 Hz ASSRs between the pre-reading and the beginning reading stage. A forward stepwise logistic regression analysis showed that literacy achievement was predictable with an accuracy of 90.4% based on a model including three significant predictors, that is, family risk for dyslexia (R = .31), phonological awareness (R = .23), and 80 Hz ASSRs (R = .26). Given that (1) abnormalities in subcortical ASSRs preceded reading acquisition in children who developed dyslexia and (2) subcortical ASSRs contributed to the prediction of literacy achievement, subcortical auditory synchronization deficits may constitute a pre-reading risk factor in the emergence of dyslexia.
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http://dx.doi.org/10.1111/desc.12945DOI Listing
November 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

Speech Envelope Enhancement Instantaneously Effaces Atypical Speech Perception in Dyslexia.

Ear Hear 2019 Sep/Oct;40(5):1242-1252

Department of Neurosciences, Research Group Experimental ORL, KU Leuven-University of Leuven, Leuven, Belgium.

Objectives: Increasing evidence exists that poor speech perception abilities precede the phonological deficits typically observed in dyslexia, a developmental disorder in learning to read. Impaired processing of dynamic features of speech, such as slow amplitude fluctuations and transient acoustic cues, disrupts effortless tracking of the speech envelope and constrains the development of adequate phonological skills. In this study, a speech envelope enhancement (EE) strategy was implemented to reduce speech perception deficits by students with dyslexia. The EE emphasizes onset cues and reinforces the temporal structure of the speech envelope specifically.

Design: Speech perception was assessed in 42 students with and without dyslexia using a sentence repetition task in a speech-weighted background noise. Both natural and vocoded speech were used to assess the contribution of the temporal envelope on the speech perception deficit. Their envelope-enhanced counterparts were added to each baseline condition to administer the effect of the EE algorithm. In addition to speech-in-noise perception, general cognitive abilities were assessed.

Results: Results demonstrated that students with dyslexia not only benefit from EE but benefit more from it than typical readers. Hence, EE completely normalized speech reception thresholds for students with dyslexia under adverse listening conditions. In addition, a correlation between speech perception deficits and phonological processing was found for students with dyslexia, further supporting the relation between speech perception abilities and reading skills. Similar results and relations were found for conditions with natural and vocoded speech, providing evidence that speech perception deficits in dyslexia stem from difficulties in processing the temporal envelope.

Conclusions: Using speech EE, speech perception skills in students with dyslexia were improved passively and instantaneously, without requiring any explicit learning. In addition, the observed positive relationship between speech processing and advanced phonological skills opens new avenues for specific intervention strategies that directly target the potential core deficit in dyslexia.
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http://dx.doi.org/10.1097/AUD.0000000000000706DOI Listing
March 2020

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

Atypical neural processing of rise time by adults with dyslexia.

Cortex 2019 04 21;113:128-140. Epub 2018 Dec 21.

KU Leuven - University of Leuven, Department of Neurosciences, Research Group Experimental ORL, Leuven, Belgium.

In recent studies phonological deficits in dyslexia are related to a deficit in the synchronization of neural oscillations to the dynamics of the speech envelope. The temporal features of both amplitude modulations and rise times characterize the speech envelope. Previous studies uncovered the inefficiency of the dyslexic brain to follow different amplitude modulations in speech. However, it remains to be investigated how the envelope's rise time mediates this neural processing. In this study we examined neural synchronization in students with and without dyslexia using auditory steady-state responses at theta, alpha, beta and low-gamma range oscillations (i.e., 4, 10, 20 and 40 Hz) to stimuli with different envelope rise times. Our results revealed reduced neural synchronization in the alpha, beta and low-gamma frequency ranges in dyslexia. Moreover, atypical neural synchronization was modulated by rise time for alpha and beta oscillations, showing that deficits found at 10 and 20 Hz were only evident when the envelope's rise time was significantly shortened. This impaired tracking of rise time cues may very well lead to the speech and phonological processing difficulties observed in dyslexia.
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http://dx.doi.org/10.1016/j.cortex.2018.12.006DOI Listing
April 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

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

The natural number bias and its role in rational number understanding in children with dyscalculia. Delay or deficit?

Res Dev Disabil 2017 Dec 15;71:181-190. Epub 2017 Oct 15.

Centre for Instructional Psychology and Technology, University of Leuven, Belgium, Dekenstraat 2, 3000 Leuven, Belgium. Electronic address:

Background: Previous research indicated that in several cases learners' errors on rational number tasks can be attributed to learners' tendency to (wrongly) apply natural number properties. There exists a large body of literature both on learners' struggle with understanding the rational number system and on the role of the natural number bias in this struggle. However, little is known about this phenomenon in learners with dyscalculia.

Aims: We investigated the rational number understanding of learners with dyscalculia and compared it with the rational number understanding of learners without dyscalculia.

Method: Three groups of learners were included: sixth graders with dyscalculia, a chronological age match group, and an ability match group.

Results: The results showed that the rational number understanding of learners with dyscalculia is significantly lower than that of typically developing peers, but not significantly different from younger learners, even after statistically controlling for mathematics achievement.

Conclusion: Next to a delay in their mathematics achievement, learners with dyscalculia seem to have an extra delay in their rational number understanding, compared with peers. This is especially the case in those rational number tasks where one has to inhibit natural number knowledge to come to the right answer.
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http://dx.doi.org/10.1016/j.ridd.2017.10.006DOI Listing
December 2017

Developmental trajectories of children's symbolic numerical magnitude processing skills and associated cognitive competencies.

J Exp Child Psychol 2018 Feb 22;166:232-250. Epub 2017 Sep 22.

Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, University of Leuven, 3000 Leuven, Belgium.

Although symbolic numerical magnitude processing skills are key for learning arithmetic, their developmental trajectories remain unknown. Therefore, we delineated during the first 3years of primary education (5-8years of age) groups with distinguishable developmental trajectories of symbolic numerical magnitude processing skills using a model-based clustering approach. Three clusters were identified and were labeled as inaccurate, accurate but slow, and accurate and fast. The clusters did not differ in age, sex, socioeconomic status, or IQ. We also tested whether these clusters differed in domain-specific (nonsymbolic magnitude processing and digit identification) and domain-general (visuospatial short-term memory, verbal working memory, and processing speed) cognitive competencies that might contribute to children's ability to (efficiently) process the numerical meaning of Arabic numerical symbols. We observed minor differences between clusters in these cognitive competencies except for verbal working memory for which no differences were observed. Follow-up analyses further revealed that the above-mentioned cognitive competencies did not merely account for the cluster differences in children's development of symbolic numerical magnitude processing skills, suggesting that other factors account for these individual differences. On the other hand, the three trajectories of symbolic numerical magnitude processing revealed remarkable and stable differences in children's arithmetic fact retrieval, which stresses the importance of symbolic numerical magnitude processing for learning arithmetic.
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http://dx.doi.org/10.1016/j.jecp.2017.08.008DOI Listing
February 2018

Do prereaders' auditory processing and speech perception predict later literacy?

Res Dev Disabil 2017 Nov 20;70:138-151. Epub 2017 Sep 20.

Department of Neurosciences, ExpORL, University of Leuven, 3000 Leuven, Belgium.

Developmental dyslexia has frequently been linked to deficits in auditory processing and speech perception. However, the presence and precise nature of these deficits and the direction of their relation with reading, remains debated. In this longitudinal study, 87 five-year-olds at high and low family risk for dyslexia were followed before and during different stages of reading acquisition. The processing of different auditory cues was investigated, together with performance on speech perception and phonology and reading. Results show no effect of family risk for dyslexia on prereading auditory processing and speech perception skills. However, a relation is present between the performance on these skills in kindergarten and later phonology and literacy. In particular, links are found with the auditory processing of cues characteristic for the temporal speech amplitude envelope, rather than with other auditory cues important for speech intelligibility. Hereby, cues embedded in the speech amplitude envelope show to be related to a broad range of phonological precursors for reading. In addition, speech-in-noise perception demonstrates to operate as the most contributing factor for later phonological awareness and to be a predictor for reading mediated by the association with phonology. This study provides behavioral support for the link between prereading speech amplitude envelope processing and speech perception for future phonology and reading.
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http://dx.doi.org/10.1016/j.ridd.2017.09.005DOI Listing
November 2017

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

A longitudinal study investigating neural processing of speech envelope modulation rates in children with (a family risk for) dyslexia.

Cortex 2017 08 25;93:206-219. Epub 2017 May 25.

Research Group Experimental ORL, Department of Neurosciences, KU Leuven - University of Leuven, Leuven, Belgium.

Recent evidence suggests that a fundamental deficit in the synchronization of neural oscillations to temporal information in speech may underlie phonological processing problems in dyslexia. Since previous studies were performed cross-sectionally in school-aged children or adults, developmental aspects of neural auditory processing in relation to reading acquisition and dyslexia remain to be investigated. The present longitudinal study followed 68 children during development from pre-reader (5 years old) to beginning reader (7 years old) and more advanced reader (9 years old). Thirty-six children had a family risk for dyslexia and 14 children eventually developed dyslexia. EEG recordings of auditory steady-state responses to 4 and 20 Hz modulations, corresponding to syllable and phoneme rates, were collected at each point in time. Our results demonstrate an increase in neural synchronization to phoneme-rate modulations around the onset of reading acquisition. This effect was negatively correlated with later reading and phonological skills, indicating that children who exhibit the largest increase in neural synchronization to phoneme rates, develop the poorest reading and phonological skills. Accordingly, neural synchronization to phoneme-rate modulations was found to be significantly higher in beginning and more advanced readers with dyslexia. We found no developmental effects regarding neural synchronization to syllable rates, nor any effects of a family risk for dyslexia. Altogether, our findings suggest that the onset of reading instruction coincides with an increase in neural responsiveness to phoneme-rate modulations, and that the extent of this increase is related to (the outcome of) reading development. Hereby, dyslexic children persistently demonstrate atypically high neural synchronization to phoneme rates from the beginning of reading acquisition onwards.
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http://dx.doi.org/10.1016/j.cortex.2017.05.007DOI Listing
August 2017

Early development and predictors of morphological awareness: Disentangling the impact of decoding skills and phonological awareness.

Res Dev Disabil 2017 Aug 20;67:47-59. Epub 2017 Jun 20.

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

Background: Morphological Awareness (MA) has been demonstrated to be influential on the reading outcomes of children and adults. Yet, little is known regarding MA's early development.

Aim: The aim of this study is to better understand MA at different stages of development and its association with Phonological Awareness (PA) and reading.

Methods And Procedures: In a longitudinal design the development of MA was explored in a group of pre-reading children with a family risk of dyslexia and age-matched controls from kindergarten up to and including grade 2.

Outcomes And Results: MA deficits were observed in the group with literacy difficulties at all time points. PA was only found to make a significant contribution to MA development at the early stages of formal reading instruction. While first-grade decoding skills were found to contribute significantly to MA in second grade.

Conclusions: Evidence supporting a bidirectional relation was found and supports the need for adequate MA intervention and explicit instruction for "at risk" children in the early stages of literacy instruction.
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http://dx.doi.org/10.1016/j.ridd.2017.05.003DOI Listing
August 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

Atypical neural synchronization to speech envelope modulations in dyslexia.

Brain Lang 2017 Jan 7;164:106-117. Epub 2016 Nov 7.

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

A fundamental deficit in the synchronization of neural oscillations to temporal information in speech could underlie phonological processing problems in dyslexia. In this study, the hypothesis of a neural synchronization impairment is investigated more specifically as a function of different neural oscillatory bands and temporal information rates in speech. Auditory steady-state responses to 4, 10, 20 and 40Hz modulations were recorded in normal reading and dyslexic adolescents to measure neural synchronization of theta, alpha, beta and low-gamma oscillations to syllabic and phonemic rate information. In comparison to normal readers, dyslexic readers showed reduced non-synchronized theta activity, reduced synchronized alpha activity and enhanced synchronized beta activity. Positive correlations between alpha synchronization and phonological skills were found in normal readers, but were absent in dyslexic readers. In contrast, dyslexic readers exhibited positive correlations between beta synchronization and phonological skills. Together, these results suggest that auditory neural synchronization of alpha and beta oscillations is atypical in dyslexia, indicating deviant neural processing of both syllabic and phonemic rate information. Impaired synchronization of alpha oscillations in particular demonstrated to be the most prominent neural anomaly possibly hampering speech and phonological processing in dyslexic readers.
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http://dx.doi.org/10.1016/j.bandl.2016.10.002DOI Listing
January 2017

The influences and outcomes of phonological awareness: a study of MA, PA and auditory processing in pre-readers with a family risk of dyslexia.

Dev Sci 2017 09 23;20(5). Epub 2016 Oct 23.

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

The direct influence of phonological awareness (PA) on reading outcomes has been widely demonstrated, yet PA may also exert indirect influence on reading outcomes through other cognitive variables such as morphological awareness (MA). However, PA's own development is dependent and influenced by many extraneous variables such as auditory processing, which could ultimately impact reading outcomes. In a group of pre-reading children with a family risk of dyslexia and low-risk controls, this study sets out to answer questions surrounding PA's relationship at various grain sizes (syllable, onset/rime and phoneme) with measures of auditory processing (frequency modulation (FM) and an amplitude rise-time task (RT)) and MA, independent of reading experience. Group analysis revealed significant differences between high- and low-risk children on measures of MA, and PA at all grain sizes, while a trend for lower RT thresholds of high-risk children was found compared with controls. Correlational analysis demonstrated that MA is related to the composite PA score and syllable awareness. Group differences on MA and PA were re-examined including PA and MA, respectively, as control variables. Results exposed PA as a relevant component of MA, independent of reading experience.
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http://dx.doi.org/10.1111/desc.12453DOI Listing
September 2017

Numerical magnitude processing impairments in genetic syndromes: a cross-syndrome comparison of Turner and 22q11.2 deletion syndromes.

Dev Sci 2017 Nov 17;20(6). Epub 2016 Oct 17.

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

Cross-syndrome comparisons offer an important window onto understanding heterogeneity in mathematical learning disabilities or dyscalculia. The present study therefore investigated symbolic numerical magnitude processing in two genetic syndromes that are both characterized by mathematical learning disabilities: Turner syndrome and 22q11.2 deletion syndrome (22q11DS). We further verified whether the phenotypic outcomes of these syndromes emerged from the same or different cognitive processes and therefore examined whether numerical impairments were related to working memory deficits, often observed in these syndromes. Participants were 24 girls with Turner syndrome, 25 children with 22q11DS and 48 well-matched typically developing control children. All children completed a symbolic numerical magnitude comparison task and four additional working memory tasks. Both groups of children with genetic syndromes showed similar impairments in symbolic numerical magnitude processing compared to typically developing controls. Importantly, in Turner syndrome, group differences in symbolic numerical magnitude processing disappeared when their difficulties in visual-spatial working memory were taken into account. In contrast, the difficulties in 22q11DS were not explained by poor visual-spatial working memory. These data suggest that different factors underlie the symbolic numerical magnitude processing impairments in both patient groups with mathematical learning disabilities and highlight the value of cross-syndrome comparisons for understanding different pathways to mathematical learning disabilities or dyscalculia.
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http://dx.doi.org/10.1111/desc.12458DOI Listing
November 2017

Symbolic magnitude processing in elementary school children: A group administered paper-and-pencil measure (SYMP Test).

Behav Res Methods 2017 08;49(4):1361-1373

Faculty of Psychology and Educational Sciences, Parenting and Special Education Research Unit, University of Leuven, Leopold Vanderkelenstraat 32, box 3765, 3000, Leuven, Belgium.

The ability to compare symbolic numerical magnitudes correlates with children's concurrent and future mathematics achievement. We developed and evaluated a quick timed paper-and-pencil measure that can easily be used, for example in large-scale research, in which children have to cross out the numerically larger of two Arabic one- and two-digit numbers (SYMP Test). We investigated performance on this test in 1,588 primary school children (Grades 1-6) and examined in each grade its associations with mathematics achievement. The SYMP Test had satisfactory test-retest reliability. The SYMP Test showed significant and stable correlations with mathematics achievement for both one-digit and two-digit comparison, across all grades. This replicates the previously observed association between symbolic numerical magnitude processing and mathematics achievement, but extends it by showing that the association is observed in all grades in primary education and occurs for single- as well as multi-digit processing. Children with mathematical learning difficulties performed significantly lower on one-digit comparison and two-digit comparison in all grades. This all suggests satisfactory construct and criterion-related validity of the SYMP Test, which can be used in research, when performing large-scale (intervention) studies, and by practitioners, as screening measure to identify children at risk for mathematical difficulties or dyscalculia.
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http://dx.doi.org/10.3758/s13428-016-0792-3DOI Listing
August 2017

Children's understanding of the addition/subtraction complement principle.

Br J Educ Psychol 2016 Sep 17;86(3):382-96. Epub 2016 Mar 17.

Centre for Instructional Psychology and Technology, KU Leuven, Belgium.

Background: In the last decades, children's understanding of mathematical principles has become an important research topic. Different from the commutativity and inversion principles, only few studies have focused on children's understanding of the addition/subtraction complement principle (if a - b = c, then c + b = a), mainly relying on verbal techniques.

Aim: This contribution aimed at deepening our understanding of children's knowledge of the addition/subtraction complement principle, combining verbal and non-verbal techniques.

Sample: Participants were 67 third and fourth graders (9- to 10-year-olds).

Methods: Children solved two tasks in which verbal reports as well as accuracy and speed data were collected. These two tasks differed only in the order of the problems and the instructions. In the looking-back task, children were told that sometimes the preceding problem might help to answer the next problem. In the baseline task, no helpful preceding items were offered. The looking-back task included 10 trigger-target problem pairs on the complement relation.

Results: Children verbally reported looking back on about 40% of all target problems in the looking-back task; the target problems were also solved faster and more accurately than in the baseline task. These results suggest that children used their understanding of the complement principle. The verbal and non-verbal data were highly correlated.

Discussion: This study complements previous work on children's understanding of mathematical principles by highlighting interindividual differences in 9- to 10-year-olds' understanding of the complement principle and indicating the potential of combining verbal and non-verbal techniques to investigate (the acquisition of) this understanding.
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http://dx.doi.org/10.1111/bjep.12113DOI Listing
September 2016

Symbolic Numerical Magnitude Processing Is as Important to Arithmetic as Phonological Awareness Is to Reading.

PLoS One 2016 4;11(3):e0151045. Epub 2016 Mar 4.

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

In this article, we tested, using a 1-year longitudinal design, whether symbolic numerical magnitude processing or children's numerical representation of Arabic digits, is as important to arithmetic as phonological awareness is to reading. Children completed measures of symbolic comparison, phonological awareness, arithmetic, reading at the start of third grade and the latter two were retested at the start of fourth grade. Cross-sectional and longitudinal correlations indicated that symbolic comparison was a powerful domain-specific predictor of arithmetic and that phonological awareness was a unique predictor of reading. Crucially, the strength of these independent associations was not significantly different. This indicates that symbolic numerical magnitude processing is as important to arithmetic development as phonological awareness is to reading and suggests that symbolic numerical magnitude processing is a good candidate for screening children at risk for developing mathematical difficulties.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0151045PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4778857PMC
July 2016

Longitudinal changes in mathematical abilities and white matter following paediatric mild traumatic brain injury.

Brain Inj 2015 19;29(13-14):1701-10. Epub 2015 Oct 19.

a Parenting and Special Education, Faculty of Psychology and Educational Sciences, University of Leuven , Leuven , Belgium .

Primary Objective: Paediatric traumatic brain injury (TBI) has been associated with acute and long-term mathematical difficulties. Little is known about the recovery of these impairments in children with mild TBI (mTBI) and their underlying pathophysiology, such as white matter abnormalities.

Research Design: A prospective longitudinal study followed the recovery of mathematical abilities and white matter in children with mTBI from the sub-acute (1 month post-injury) to chronic stage (6-8 months post-injury) of recovery.

Methods And Procedures: Twenty children with mTBI and 20 matched controls completed mathematics tests. Diffusion Tensor Imaging (DTI) metrics of white matter pathways corpus callosum (CC), superior and longitudinal fasciculi were examined with DTI-tractography.

Main Outcomes And Results: Mathematical difficulties and white matter abnormalities in the CC observed shortly after the injury resolved after 6-8 months of recovery. Children with mTBI continued to show working memory deficits. Longitudinal DTI data suggest continued maturation of the CC in controls, but little maturation of the damaged CC in children with mTBI.

Conclusions: Children with mTBI recovered in terms of mathematical abilities and white matter. These children continued to show working memory deficits, which might interfere with learning at school.
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http://dx.doi.org/10.3109/02699052.2015.1075172DOI Listing
October 2016

Arithmetic difficulties in children with mild traumatic brain injury at the subacute stage of recovery.

Dev Med Child Neurol 2015 Nov 13;57(11):1042-8. Epub 2015 Aug 13.

Department of Development and Regeneration, Biomedical sciences group, University of Leuven, Leuven, Belgium.

Aim: Arithmetic difficulties have been reported in children with mild traumatic brain injury (mTBI), but the electrophysiological abnormalities underlying these impairments remain unknown. We therefore used event-related potentials (ERPs) to investigate brain functioning during arithmetic in children in the subacute phase after mTBI.

Method: The participants comprised 16 children with mTBI at the subacute phase of recovery (10 males, mean age 10y 8mo; six females, mean age 10y 8mo) and 16 well-matched comparison children (11 males, mean age 10y 11mo; five females, mean age 10y 6mo). All children were asked to solve single-digit addition problems of small (sum ≤10) and large problem size (sum >10) and ERPs were simultaneously recorded.

Results: Children with mTBI performed significantly less accurately (mean 81%) than comparison children (mean 91%) on the large (p=0.026) but not on the small problems (p=0.171). We observed no group differences in the early ERP components P1, N1, P2, and N2 (all p values ≥0.241), yet significant group differences (p=0.019) emerged for the late positivity component (LPC), which showed smaller mean amplitudes (mean 8.35μV) in mTBI patients than comparison children (mean 12.95μV).

Interpretation: Immediately after the injury, arithmetic difficulties in children with mTBI are particularly pronounced on more complex arithmetical problems that are less automated. This is reflected in the ERP pattern, with decreased LPC but normal N2 and early ERP components.
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http://dx.doi.org/10.1111/dmcn.12858DOI Listing
November 2015