Brown Bag du 23/11/17 à 11h30 Irene Altarelli, INSERM-CEA Cognitive Neuroimaging Lab, Neurospin

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Neuroanatomical correlates of developmental dyslexia

Developmental dyslexia is a specific learning disorder, affecting 5 to 7% of school-age children. This disorder impacts reading abilities, despite adequate educational conditions, normal intelligence and the absence of major sensory deficits. A genetic basis of developmental dyslexia exists, with heritability estimates of 50 to 60%. Moreover, from a neurobiological point of view, post mortem investigations of dyslexic brains have revealed the presence of various types of cortical anomalies. The aim of the work presented here is to determine the neuroanatomical correlates of the disorder in vivo, with the broader goal of identifying associations between genetic variants, brain anatomy and cognitive impairments in developmental dyslexia. To this end, we compared different cortical measures across dyslexic and control children, using magnetic resonance imaging.

This work was partly extended to pre-readers at familial risk of developmental dyslexia, in order to investigate the anatomical risk factors involved. It also included comparisons across languages of varying orthographic transparency, with the objective of evaluating the consistency of anatomical correlates across different orthographic contexts.

Importantly, on top of offering a better characterisation of the brain bases of the disorder, our results stress the importance of sex, a long neglected factor in dyslexia.