Mother-child similarity in brain morphology: A comparison of structural characteristics of the brain\u27s reading network

Background: Substantial evidence acknowledges the complex gene-environment interplay impacting brain development and learning. Intergenerational neuroimaging allows the assessment of familial transfer effects on brain structure, function and behavior by investigating neural similarity in caregiver-child dyads. Methods: Neural similarity in the human reading network was assessed through well-used measures of brain structure (i.e., surface area (SA), gyrification (lG), sulcal morphology, gray matter volume (GMV) and cortical thickness (CT)) in 69 mother-child dyads (children\u27s age~11 y). Regions of interest for the reading network included left-hemispheric inferior frontal gyrus, inferior parietal lobe and fusiform gyrus. Mother-child similarity was quantified by correlation coefficients and familial specificity was tested by comparison to random adult-child dyads. Sulcal morphology analyses focused on occipitotemporal sulcus interruptions and similarity was assessed by chi-square goodness of fit. Results: Significant structural brain similarity was observed for mother-child dyads in the reading network for lG, SA and GMV (r = 0.349/0.534/0.542, respectively), but not CT. Sulcal morphology associations were non-significant. Structural brain similarity in lG, SA and GMV were specific to mother-child pairs. Furthermore, structural brain similarity for SA and GMV was higher compared to CT. Conclusion: Intergenerational neuroimaging techniques promise to enhance our knowledge of familial transfer effects on brain development and disorders

Predicting early signs of dyslexia at a preliterate age by combining behavioral assessment with structural MRI

Background: Recent studies suggest that neurobiological anomalies are already detectable in pre-school children with a family history of developmental dyslexia (DD). However, there is a lack of longitudinal studies showing a direct link between those differences at a preliterate age and the subsequent literacy difficulties seen in school. It is also not clear whether the prediction of DD in pre-school children can be significantly improved when considering neurobiological predictors, compared to models based on behavioral literacy precursors only. Methods: We recruited 53 pre-reading children either with (N=25) or without a family risk of DD (N=28). Quantitative T1 MNI data and literacy precursor abilities were assessed at kindergarten age. A subsample of 35 children was tested for literacy skills either one or two years later, that is, either in first or second grade. Results: The group comparison of quantitative T1 measures revealed significantly higher T1 intensities in the left anterior arcuate fascicle (AF), suggesting reduced myelin concentration in preliterate children at risk of DD. A logistic regression showed that DD can be predicted significantly better (p=.024) when neuroanatomical differences between groups are used as predictors (80%) compared to a model based on behavioral predictors only (63%).The Wald statistic confirmed that the T1 intensity of the left AF is a statistically significant predictor of DD (p<.05). Conclusions: Our longitudinal results provide evidence for the hypothesis that neuroanatomical anomalies in children with a family risk of DD are related to subsequent problems in acquiring literacy. Particularly, solid white matter organization in the left anterior arcuate fascicle seems to play a pivotal role

White matter connectome associations with reading functions in children

This thesis investigated associations between the white matter connectome and reading in children with a wide range of reading abilities. It is well established that the connectome supports the interplay among brain regions and connections within an integrated system. In this dissertation, I examine the hypothesis that it could therefore represent multiple mapping processes among reading components and further explain variations in reading performance. Such associations between the organization of the connectome and reading skills have not been well explored. This thesis aimed to address this issue by considering both the relationship between connectome measures and standardized reading performance out of scanner, and neural activations during in-scanner reading tasks. Chapter 2 examined the rich-club organization of the white matter connectome and its association with sight word reading, phonemic decoding, reading comprehension, and rapid automatized naming in children. I found that feeder connections that link hub and reading network regions were associated with word-level reading skills. Chapter 3 further examined how the left thalamus influences reading skills by coordinating information flow between the reading network and hub regions. Results showed that the efficiency metrics and routing cost of the left thalamus within a subnetwork, which contains the reading network and hub regions, were associated with rapid automatized naming and phonemic decoding scores, respectively. Chapter 4 applied network control theory to investigate if the white matter connectome could explain the dynamics of functional activation. Specifically, I examined if control energy, which reflects the level of cognitive demands from a task, showed differences across different conditions of an in-scanner rhyming task. I found that conditions requiring more effort were associated with higher control energy within reading network areas. In addition, the control energy of the superior temporal gyrus and fusiform gyrus showed dissociations regarding different modalities of stimulus presentation. Moreover, children with better word-level reading scores required lower control energy. Chapter 5 summarizes the findings and discusses their implications to the connectome-reading relationship

Estudo de impacto de aplicação de programa fonolinguístico e gestual de intervenção em leitura e ortografia em crianças com dislexia

Para aceder ao áudio "Rimas Rimadas", por favor contactar a Biblioteca Fernando Pessoa, através do seguinte endereço eletrónico: [email protected] sociedades modernas, o papel da leitura é fundamental. Assim, qualquer défice na capacidade de ler pode afetar significativamente as aspirações de uma pessoa. Tendo como base o funcionamento cerebral dos normoleitores, a neuroimagem identificou diferenças funcionais e estruturais relacionadas com dificuldades específicas de leitura. Há ampla evidência de que a intervenção especializada é eficaz na melhoria da proficiência em leitura e escrita de crianças com dislexia, mas em Portugal escasseiam programas de reeducação desta área, elaborados à luz das neurociências. Com esta investigação pretendemos atingir três grandes objetivos que deram origem a dois estudos. O primeiro visou identificar crianças com dislexia de dois agrupamentos de escolas do 1º ciclo, para criar uma amostra e, secundariamente, comparar a prevalência da dislexia nesses agrupamentos com a de estudos até então levados a cabo. Realizaram-se estatísticas descritivas e fez-se a análise de simetria da distribuição das frequências, através da utilização dos coeficientes de assimetria/curtose. O segundo estudo contemplou a elaboração de um programa de reeducação da dislexia e disortografia, intensivo, sistemático, com ensino explícito e assente num método fónico e gestual e a avaliação do seu impacto. O design da investigação envolveu um grupo experimental (GE) e um de controlo (GC) e a realização de pré e pós-teste. Para avaliar a sua eficácia, utilizaram-se testes t para amostras independentes e t para amostras emparelhadas. O pressuposto da homogeneidade de variâncias foi avaliado através do teste de Levene. Participaram na triagem inicial 577 crianças do 2º e 3º ano, de dois agrupamentos de escolas do concelho da Maia. Identificamos 30 crianças com dislexia (N=30) e os resultados indicam uma prevalência da dislexia de 5,19%, valor muito próximo do de outras publicações para o português europeu. Os resultados do segundo estudo apontam para a eficácia do programa de reeducação, registando-se valores mais elevados em todas as provas do pós-teste, no GE. Nas variáveis: consciência fonémica, precisão leitora e de escrita, a diferença de resultados entre os dois grupos é expressiva; ao nível da velocidade leitora a progressão do GE foi menos visível. Os resultados são discutidos e sugeridos novos estudos.In modern society, reading is essential. Any deficit in the capacity of reading can significantly affect one person’s life aspirations. Having as a baseline the cerebral activity of normal-readers, neuroimaging has identified functional and structural differences related to specific difficulties of reading. There is vast evidence that a specialized intervention is effective in the improvement of reading and writing proficiency of children with dyslexia, but in Portugal there is a lack of re-education programs in this area that are shaped around the neurosciences. With this investigation, we set out to achieve three principal goals that originated two studies. The first study aimed to identify children with dyslexia from two groups of primary schools in order to create a sample base, and then compare the occurrence of dyslexia in those schools with the results of previous researches. Descriptive statistics took place, and an analysis of the symmetry of the frequency distribution was completed based on the coefficients of skewness and kurtosis. The second study planned the creation of a re-education programme of dyslexia and dysortography, intensive and systematic with explicit teaching based on phonetic and sign methods, and the evaluation of its impact. The investigation involved an experimental group (GE) and a control group (GC) and the completion of a pre and post-test. In order to evaluate its effectiveness, t tests for independent samples and t testes for mixed samples were used. The assumption of variances homogeneity was appraised using the Levene test. 577 children from 2nd and 3rd year from two groups of schools in Maia participated in the initial sorting. 30 children with dyslexia (N=30) were identified and the results suggest a prevalence of dyslexia of 5.19%, a result very close to the ones of other publications for the European Portuguese. The results of the second study propose the effectiveness of the re-education programme, showing more elevated values in all the tests of the post-test GE. Whilst in the variables of phonemic conscience and precision of reading and writing, the difference in the results between the two groups is significant; in the speed of reading variable, the progression of GE was less prominent. The results are discussed in detail, and new studies are proposed.Dans les sociétés modernes, le rôle de la lecture est fondamental. Ainsi, tout déficit dans la capacité de lire peut affecter de manière significative les aspirations d'une personne. Sur la base du fonctionnement cérébrale des normoléitres, la neuroimagerie a identifié des différences fonctionnelles et structurelles liées à des difficultés de lecture spécifiques. Il existe de nombreuses preuves qu'une intervention spécialisée est efficace pour améliorer la maîtrise de la lecture et de l'écriture chez les enfants dyslexiques, mais, au Portugal, il existe peu de programmes de rééducation dans ce domaine, élaborés à la lumière des neurosciences. Avec cette recherche scientifique, nous avons l'intention d’atteindre trois grands objectifs qui ont donné lieu à deux études. Le premier visait à identifier les enfants dyslexiques de deux groupes d'écoles élémentaires, à créer un échantillon et, secondairement, à comparer la prévalence de la dyslexie dans ces groupes avec celle des études menées jusque-là. Des statistiques descriptives ont été réalisées et l'analyse de symétrie de la distribution de fréquence a été effectuée, en utilisant les coefficients d'asymétrie et de kurtosis. Le deuxième étude comprenait l'élaboration d'un programme de rééducation intensive et systématique de la dyslexie et de la dysorthographie, avec un enseignement explicite et basé sur une méthode phonique et gestuelle et l'évaluation de son impact. La conception de recherche scientifique a impliqué un groupe expérimental (GE) et un groupe contrôle (GC) et la performance des pré et post-tests. Pour évaluer son efficacité, des tests t pour des échantillons indépendants et t pour des échantillons appariés ont été utilisés. L'hypothèse d'homogénéité des variances a été évaluée à l'aide du test de Levene. 577 enfants de la 2e et de la 3e année ont participé au dépistage initial, dans deux groupes d'écoles de la commune de Maia. Nous avons identifié 30 enfants dyslexiques (N = 30) et les résultats indiquent une prévalence de la dyslexie de 5,19%, une valeur très proche de celle d'autres publications pour le portugais européen. Les résultats de la deuxième étude indiquent l'efficacité du programme de rééducation, des valeurs plus élevées étant enregistrées dans tous les tests post-test au GE. Dans les variables: conscience phonémique, précision de lecture et d'écriture, la différence de résultats entre les deux groupes est significative; en termes de vitesse de lecture, la progression du GE a été moins visible. Les résultats sont discutés et d'autres études sont suggérées