The heterogeneity of reading and writing difficulties

Abstract

Dyslexia and dysgraphia are two intertwined difficulties. However, limited research has investigated their relationship, especially in Chinese. The inconsistency in the definition of these learning difficulties obstructs effective research and understanding of the phenomenon. The current thesis aimed at exploring the connection between dyslexia and dysgraphia to reveal the heterogeneity of reading and writing difficulties in Chinese. Study 1 identified the presence of dissociated impairments in reading and spelling of Chinese and evaluated the role of handwriting ability on literacy skills development. The studies oversampled children with reading and writing difficulties, among the 307 participants included after selection, 117 participants were identified as having both reading and writing (dictation) difficulties; 53 participants only have difficulties in writing (dictation) and 11 participants only have difficulties in reading. Handwriting fluency was found to have a unique contribution to reading and dictation after controlling for rapid naming, phonological memory and visual memories. Study 2 investigated the partial cues reading theory for explaining reading and writing dissociation, and relevant visual perceptual variables were examined. The results support the partial cues reading theory, suggesting an incomplete orthographic lexical attainment in children with the dictation-only deficit. This group of participants was also found to have a wide perceptual mode, instead of a global information processing tendency. Replicating previous findings, habitual inattentiveness towards characters’ details was found to be a unique characteristic of the Dictation-only Deficit group. Overall speaking, the results provide insight into the heterogeneity of reading and writing difficulties in Chinese. A theoretical model is proposed to explain the relationships between different factors related to literacy acquisition. This research project could be the first study in Chinese to extensively examine the reading and writing dissociation phenomenon. The evidence obtained from the study strongly challenge the status quo of the definition of reading and writing difficulties. The distinct grouping of dyslexia and dysgraphia is incapable of capturing the distinct multi-dimensional heterogeneous nature of reading and writing difficulties. A holistic dimensional approach to diagnosis is proposed as a future research direction.