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Age-related changes in individuals with and without reading disability: behavioral and fMRI evidence

Poster D46 in Poster Session D, Wednesday, October 25, 4:45 - 6:30 pm CEST, Espace Vieux-Port
This poster is part of the Sandbox Series.

Xiaohui Yan¹, Guoyan Feng², Yu Wu³, Fan Cao⁴; ¹University of Hong Kong

Reading disability (RD) is a common developmental disorder with a prevalence of 10% across languages, however, the etiology has been poorly understood. Developmental studies are important in differentiating persistent deficits, developmental delays and accumulative effects of RD. By using a cross-sectional design, we compared Chinese children and adults with and without RD in the behavior and brain function. In the behavioral Level, we found persistent deficits in phonological awareness and word reading speed, suggesting definitive features of RD. We also found deficits in word reading accuracy only in children but not adults with RD, suggesting a developmental delay. Furthermore, deficits in sentence reading fluency were more evident in adults than children with RD, suggesting that this is an accumulative effect of RD which is more severe with time passing by. In the brain level, we found reduced brain activation in the left inferior frontal gyrus (IFG) only in children with RD than age controls but not in adults with RD, suggesting developmental delay. In contrast, we found reduced brain activation in the left inferior temporal gyrus (ITG) in adults with RD than age controls, and there was a less reduction in children with RD, suggesting that this is an accumulative effect of RD, because the abnormality is greater in adults than children with RD. These findings were replicated in three tasks, namely, an auditory rhyming task, a visual rhyming task, and a visual spelling task. These findings could be explained by greater developmental increase in the left IFG in RD readers than age controls and greater developmental increase in the left ITG in age controls than in RD readers. Further analyses revealed that the left IFG was correlated with word decoding accuracy in children with RD and the left ITG was correlated with sentence reading fluency in adults with RD, suggesting their different functions in reading. Taken together, our results suggest that individuals with RD catch up on phonological reading by involving the left IFG to an appropriate degree, but they can never reach fluent orthographic reading in the left ITG. The current study advances our understanding of the prognosis of RD.

Topic Areas: Disorders: Developmental, Reading