Abstract The possible mechanisms of developmental dyslexia mainly include the hypothesis of language framework and the hypothesis of non-verbal framework. The language framework assumes that people with developmental dyslexia may exhibit defects in phonetic awareness, rapid naming, phonetic memory, and orthographic processing. Studies of developmental dyslexia in Chinese have found that deficiencies in orthography may be an important cause of dyslexia, but there are diverse views and opinions regarding orthography processing. This article sorts out the research progress in behavioral and neuroimaging aspects of orthography studies, and provides references for further development of processing test materials and methods in the research of processing mechanism of developmental dyslexia orthography.

Objective: To characterize visual attention span in children with developmental dyslexia in Xinjiang and to explore the effects of action video game training on visual attention span,and to provide a reference for improving the visual attention span of children with dyslexia. Methods: Students from grade 3 to 5 in primary schools of Xinjiang were selected by using random clustering sampling method from July to November 2020,a total of 120 developmental dyslexia group (Group-DD), chronological age matched group (Group-CA) and reading level matched group (Group-RL) were selected and compared with visual attention spans, action video games were used to conduct intervention training for DD children, variance analysis was used to study the variation of visual attention span. Results: The accuracy and discrimination index of Group-DD (0.68±0.10, 1.21±0.87) were lower than those of Group-CA (0.77±0.99, 1.80±0.83) and Group-RL (0.71±0.11, 1.50±0.75) ( F =21.26, 15.19, P <0.05);there was no significant difference in reaction time among the three groups( P >0.05). There were statistically significant differences in the accuracy of visual attention span (0.63±0.12, 0.71±0.11,0.70±0.10), response time (760.51±185.83, 782.74±149.20, 857.27± 155.44 ), and discrimination (0.84±0.81, 1.51±0.19, 1.29±0.10) among children of different grades ( F =6.37，3.81，3.16， P < 0.05 ). After 12 hours of action video game training, the accuracy and discrimination of Group-DD intervention group (0.74±0.10, 1.53±0.88) were higher than those of Group DD control group (0.68±0.14, 1.06±0.97)( P <0.05), and there was no significant difference between Group DD intervention group and Group RL (0.76±0.12, 1.73±0.71) ( P >0.05), but there was statistical difference between Group DD intervention group and Group-CA (0.81±0.94, 2.17±0.79) ( P <0.05). Conclusion Children with dyslexia have deficits in visual attention span, with grade difference. Action video game intervention can improve visual attention span ability of developmental dyslexia children to some extent.