Li Xiu-hong, Jing Jin, Zou Xiao-bing, Huang Xu, Jin Yu, Wang Qing-xiong, Chen Xue-bin, Yang Bin-rang, Yang Si-yuan
Faculty of Maternal and Child Health, Preventive Medicine Institute, Department of Public Health, Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
Chin Med J (Engl). 2009 Feb 5;122(3):267-71.
Currently, whether or not there is visuospatial impairments in Chinese dyslexic children is still a matter of discussion. The relatively recent application of an eye-tracking paradigm may offer an opportunity to address this issue. In China, in comparison with reading studies, there have not been nearly as many eye movement studies dealing with nonreading tasks such as picture identification and whether Chinese children with dyslexia have a picture processing deficit is not clear. The purposes of the present study were to determine whether or not there is visuospatial impairments in Chinese dyslexic children. Moreover, we attempted to discuss whether or not the abnormal eye movement pattern that dyslexic subjects show during reading of text appropriate for their age is a consequence of their linguistic difficulties.
An eye-link II High-Speed Eye Tracker was used to track the series of eye-movement of 19 Chinese dyslexic children and 19 Chinese normal children. All of the subjects were presented with three pictures for this eye-tracking task and 6 relative eye-movement parameters, first fixation duration, average fixation duration, average saccade amplitude, mean saccade distance, fixation frequency and saccade frequency were recorded for analysis.
Analyzing the relative parameter among three pictures, except for the fixation frequency and the saccade frequency, other eye-movement parameters were significantly different among the three pictures (P<0.05). Among the three pictures, the first fixation duration was longer, and the average fixation duration, the average saccade amplitude and the mean saccade distance were shorter from picture 2 to picture 3. Comparing all eye-movement parameter between the two groups, the scores of average saccade amplitude (P=0.017) and the mean saccade distance (P=0.02) were less in the dyslexia group than in the normal group (P<0.05), other parameters were the same in the two different groups (P>0.05).
The characteristics of the pictures can significantly influence the visuospatial cognitive processing capability of the Chinese children. There is a detectable disability for the Chinese dyslexic children in the visuospatial cognitive processing: their saccade amplitude and mean saccade distance are shorter, which may be interpreted as specific for their reading disability.
目前，中国诵读困难儿童是否存在视觉空间障碍仍存在争议。眼动追踪范式的最新应用可能为解决这一问题提供契机。在中国，与阅读研究相比，处理图片识别等非阅读任务的眼动研究相对较少，且尚不清楚中国诵读困难儿童是否存在图片处理缺陷。本研究的目的是确定中国诵读困难儿童是否存在视觉空间障碍。此外，我们试图探讨诵读困难受试者在阅读适合其年龄的文本时表现出的异常眼动模式是否是其语言困难的结果。
使用Eye-link II高速眼动仪追踪19名中国诵读困难儿童和19名中国正常儿童的一系列眼动。所有受试者在这项眼动追踪任务中观看三张图片，并记录6个相关眼动参数，即首次注视持续时间、平均注视持续时间、平均扫视幅度、平均扫视距离、注视频率和扫视频率，用于分析。
分析三张图片之间的相关参数，除了注视频率和扫视频率外，其他眼动参数在三张图片之间存在显著差异（P<0.05）。在三张图片中，从图片2到图片3，首次注视持续时间较长，而平均注视持续时间、平均扫视幅度和平均扫视距离较短。比较两组之间的所有眼动参数，诵读困难组的平均扫视幅度得分（P=0.017）和平均扫视距离得分（P=0.02）低于正常组（P<0.05），两组之间的其他参数相同（P>0.05）。
图片的特征可显著影响中国儿童的视觉空间认知加工能力。中国诵读困难儿童在视觉空间认知加工方面存在明显缺陷：他们的扫视幅度和平均扫视距离较短，这可能被解释为其阅读障碍的特异性表现。
