发展性阅读障碍的视觉空间注意加工能力

Visual-spatial attention processing in developmental dyslexia

鉴于阅读起始于基础视觉加工阶段,越来越多的研究者开始关注阅读障碍者的视觉空间注意加工能力。视觉空间注意是指个体对视觉刺激的空间位置的注意,可通过线索提示、视觉搜索和视觉注意广度等视觉任务来考察。大量国内外研究发现,发展性阅读障碍者在视觉空间注意任务下表现出行为和神经活动方面的异常。其中的神经机制问题不仅反映在与视觉空间注意有关的顶叶区域激活异常,还存在于脑区间功能连接异常(如顶叶区域与字形加工区的功能连接)。未来研究还需利用横断和追踪研究探讨阅读障碍与视觉空间注意能力发展关系的内在机制,以及探究语言特性对阅读障碍者视觉空间注意缺陷的可能调节作用。

Considering basic visual decoding is the first step of reading, a growing group of studies focused on the visual-spatial attentional processing of the dyslexics. Visual-spatial attention refers to attentional processes that select visual stimuli based on their spatial location, and it can be measured by a set of visual tasks, such as visual search task, visual attention span task, Posner cue task. Many studies in the context of alphabetic language and Chinese reported that individuals with developmental dyslexia may exhibit poor behavioral performance and abnormal neural activity in visual-spatial attention tasks. The underlying mechanism of the relevant neural deficit may not only stem from the atypical activation in the parietal gyrus which were responsible for the visual-spatial attention, but also might be associated with weak functional connectivity between brain regions （e.g., the functional connectivity between parietal lobe and visual word form area）. Future studies should explore the development in visual-spatial attention of the dyslexics by cross-sectional and longitudinal studies. Meanwhile, it is necessary to investigate the possible modulation of language characteristics on visual-spatial attention deficit of dyslexia.