Prevalence of isolated reading and spelling difficulties in Chinese: Differential demand of lexical route in reading and spelling

Prevalence of isolated reading and spelling difficulties in Chinese: Differential demand of lexical route in reading and spelling

First Author: Edmond Hong Kei Cheung -- University of Hong Kong
Additional authors/chairs: 
Connie S.H. Ho; David W. Chan; Kevin K. H. Chung; S. M. Tsang; S.H. Lee; Cathy Y. C. Fong; Jocelyn C.Y. Kwok
Keywords: Spelling, reading and writing relationship, Dyslexia, Lexical, Chinese
Abstract / Summary: 

Purpose
The dissociation of reading and spelling difficulties indicate potential partial independence of these two highly associated abilities. Limited research has explored the dissociation in non-alphabetic languages, and it is unclear how the dissociation may manifest under the lexical route. This study aims to estimate the prevalence rate and examine the characteristics of isolated Reading Difficulties (iRD) and isolated Spelling Difficulties (iSD) in Chinese.

Method
A representative sample of 516 Chinese students in Hong Kong was recruited. Students are grouped based on their literacy attainment. Their performances on various psycholinguistics skills are compared, including rapid naming speed, morphological awareness, visual-orthographic skills, and phonological memory.

Results
7% and 6.6% of the sample are identified as iRD group and iSD group respectively. The iSD group performed significantly worse than control in visual-orthographic skills. iRD group performed significantly worse than control in phonological working memory before correction for family-wise error, but not after the correction.

Conclusion
The results indicate the existence of dissociated reading and spelling difficulties in Chinese and imply potential independence of the two abilities under the lexical process. The differential demand hypothesis of reading and spelling is partially supported, where spelling demands a higher quality of orthographic information and reading demands a higher quality of phonological information. Children with iSD have shown deficits in visual-orthographic processing while those with iRD exhibited an overall disadvantage in phonological working memory. However, the results for the latter part is mixed and further investigation is needed. Suggestions on differential diagnosis will be discussed.