Neural mechanism of deficits in Chinese developmental dyslexia

Abstract

Objective To study on the neural mechanism of deficits in Chinese developmental dyslexia from the aspects of the phonological processing, orthographic skills, visual magnocellular function and cerebellum function. Methods Critical words in Chinese and English (e.g. dyslexia, reading development, Chinese, neural) and formula (e.g. Chinese and (reading development) and (neural or neuroimage or fMRI or ERP or brain area) related with the present topic were searched among the article abstracts in Chinese and foreign databases (e.g. CNKI, Pubmed, Sciencedirect) from July to December, 2014. Results Fifty-two relevant articles were gained access to the database. Referring to the present topic, research on the neural mechanism of dyslexia with neuroimaging technique was reserved, while the studies in which the reading impairment of the participants was caused by acquired factors were eliminated. Finally, thirty-three valid articles were retained. Conclusion According to previous studies, although there might be similarities in cognitive deficits of dyslexia between alphabetic languages and Chinese, it was still found that the Chinese children with developmental dyslexia exhibited abnormal neural activities and impaired brain structures in areas associated with Chinese phonology (i.e. left middle frontal gyrus, which was different from the left inferior frontal gyrus always related with phonological processing in alphabetic languages) and orthographic skills (right occipitotemporal areas which was responsible for the visuospatial processing), revealing language specificity of Chinese to some extent. However, some other studies reported the similarities in neural mechanisms of dyslexia across languages. Therefore, more studies were required to further examine the cross-cultural mechanism of the neural activity regarding the developmental dyslexia. Meanwhile, researches on the aspects of general perception showed Chinese dyslexic individuals had deficits in visual magnocellular function, and cerebellum. Future studies were required to explore the relationship between the linguistic and non-linguistic deficits. Key words: Developmental dyslexia; Chinese reading; Language skills; General perception; Neural mechanism