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

Reading disability (RD) is a developmental neurological disorder with high prevalence across languages; however, the developmental differences in the behavior and brain of individuals with RD remain poorly understood, especially in Chinese RD. In the current study, we aimed to differentiate persistent deficits in Chinese children and adults with RD, differences that are evident only in children but not adults with RD, and differences that are more severe in adults than children with RD. In a cross-sectional design, we compared behavioral performances in a battery of reading tests and brain activities in three tasks in Chinese children (N = 83, mean age = 11) and adults (N = 94, mean age = 20) with and without RD. We found that phonological deficits were persistent across children and adults with RD, while deficits in word decoding accuracy were only evident in children but not adults with RD. Moreover, deficits in sentence reading fluency were more severe in adults than children with RD. In the brain, we found persistent reduction of brain activation in the left inferior parietal lobule (IPL), suggesting neural signature of RD. We found greater reduction of brain activation in the left inferior frontal gyrus (IFG) in children with RD than in adults with RD, suggesting a developmental delay and/or performance effect. On the other hand, a reduction of brain activation in the left inferior temporal gyrus (ITG) was more salient in adults with RD than in children with RD, due to greater developmental increase in typical readers than in RD readers, ultimately indicating accumulative effects of RD. The results were replicated in multiple tasks and samples. It contributes to advancing our understanding of the etiology and prognosis of RD. The findings also have practical implications in precise diagnosis and interventions for RD at different ages.