The Oculormotor Characters Of Chinese Developmental Dyslexia

In current study eye-tracker was used to explore the oculomotor characters and reading development model of the developmental dyslexia with their age-matched and ability-matched children. Two preliminary experiments and six experiments were included in this study.The purpose of preliminary experiment1was to screen Chinese developmental dyslexia. The assessment of vocabulary of Chinese characters for primary school (Wang&Tao,1996), the test of Chinese reading comprehension (Leong&Tse,2008) and Raven Standard Progressive Matrices Test were used to test390primary pupils. Then we selected20developmental dyslexia and their age-matched children from forth-and fifth-graders and20reading ability-matched children from third-graders.In experiment1, the moving window paradigm was used to explore the perceptual span of the developmental dyslexic children and their age-matched and ability-matched children. The results showed that the right perceptual span of dyslexics was about one to two Chinese characters. The fine information processing span of dyslexics was about one Chinese character which was similar to that of their ability-matched children. On the other hand, the gross information processing span of dyslexics which was about two Chinese characters was smaller than that of their ability-matched children which was about three Chinese characters. This indicated that the ability of planning saccade of dyslexics was relatively poorer than their ability-matched children. The right span of age-matched children was distinctly larger than that of dyslexics. The fine information processing span of ability-matched children was approximately two Chinese characters and that of gross information was about three Chinese characters.In experiment2, the boundary paradigm was used to explore the preview effects of the developmental dyslexic children and their matched children. The results found that dyslexics and their ability-matched ones could acquire orthographic preview benefits during analysis of gaze duration and regression path reading time while age-matched children could obtain strong orthographic preview benefits and a little phonological preview benefits.In experiment3, the disappearing text paradigm was adopted. Four text appearing time(40ms、80ms、120ms、normal text) was set to explore the speed of capturing visual information of the developmental dyslexic children and their matched children. The results showed that the speed of capturing information of the dyslexic was about120ms which was the slowest. The speed of the ability-matched children was about80ms while that of the age-matched children was40-80ms. All children could accordingly change their reading strategy when the text appearing time was short.Preliminary experiment2was undertaken to analyze the main subtypes of the Chinese developmental dyslexia. Thirty-seven dyslexics were selected from519fourth-and fifth-graders with the same means used in preliminary experiment1. And then four reading-related cognitive skills were examined, including phonological awareness, morphological awareness, orthographic awareness and rapid automatic naming. Based on the scores of ability-match children standard deviation cutoff criterion was adopted to analyze the subtypes of dyslexia. The results showed that the proportion of the dyslexics with phonological awareness deficit was the largest and secondly the dyslexics with orthographic awareness deficit. Finally, the dyslexics with single phonological awareness deficit, single orthographic awareness deficit, and phonology-orthographic awareness mixed deficit and slight deficit were defined as the main subtypes of dyslexia in current study.Experiment4was carried out to investigate the perceptual span of main subtypes of dyslexia. The results found that the right perceptual span of the dyslexics with single phonological awareness deficit and single orthographic awareness deficit was about one to two Chinese characters which were similar with that of ability-matched children. The perceptual span of dyslexics with phonology-orthographic awareness mixed deficit was the most small which was about one Chinese character to the right of fixation. The right perceptual span of the dyslexics with slight deficit was about two to three Chinese characters which was similar with that of age-matched children. In experiment5, the preview effects of main subtypes of dyslexia were explored. The results were as follows:the dyslexics with slight deficit could obtain orthographic information from parafoveal whereas the preview effect was not stable during the early stage of reading process. The dyslexics with single deficit could acquire preview effects only during analysis of gaze duration while the dyslexics with single phonological deficit could receive orthographic information from parafoveal vision and the dyslexics with single orthographic deficit receive phonological information. The dyslexics with mixed deficit could not obtain phonological or orthographic preview benefits.Experiment6was conducted to investigate the speed of acquiring information of the main subtypes of dyslexia. The results found that the speed of acquiring information of dyslexics with single deficit was about120ms. The speed of dyslexics with slight deficit was about80ms while their reading strategies were similar with matched children when the very short time of text presentation. The dyslexics with mixed deficit need at least120ms time to obtain reading information.In summary, the conclusions are as follows:(1) the oculormotor characteristics of dyslexics were not different from their ability-matched children whereas behind of age-matched children.(2) There were differences between the main subtypes of dyslexia. The discrepancy was on the small side between the dyslexics with slight deficit and their age-matched children. The speed of acquiring information of the dyslexics with single deficit was slower than that of ability-matched children. The development of oculormotor of dyslexics with mixed deficit was behind of ability-matched ones.