The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities, Faculty of Education, University of Haifa, Haifa, Israel.
Clin Neurophysiol. 2011 Feb;122(2):284-98. doi: 10.1016/j.clinph.2010.06.029. Epub 2010 Jul 24.
The role of visual processing deficits in dyslexia remains unclear and continues to stir controversy. Most studies to date have used alphabetic and or other language-dependent patterns. The current study compares how dyslexics and regular readers process non-alphabetic visual patterns.
The stimuli were black and white drawings, 50 meaningful (concrete objects) and 50 meaningless (pseudo-objects with no linguistic name) presented visually on a computer screen. Measures included behavioral accuracy and reaction time, event-related potential (ERP), and low resolution electromagnetic tomography (LORETA). The subjects were 15 dyslexic and 15 aged-matched regular readers.
The dyslexics exhibited significantly longer reaction time and shorter latencies of P1 and P2 components to both objects and pseudo-objects compared to the regular readers. Data from the LORETA solution analysis indicated significantly different brain activity between the two groups: both exhibited higher left hemisphere activation when viewing objects compared to pseudo-objects; and dyslexics exhibited lower left hemisphere activation when viewing objects and higher right hemisphere activation when viewing pseudo-objects during the early stages of processing.
The results support the notion that brain activation of dyslexic readers differs from that of the regular readers when processing non-alphabetic patterns, and that the differences appear from the early stage of processing.
These results emphasize that differences in brain activity between dyslexic and regular readers can be seen even in a non-alphabetic task, and in early stages of processing.
阅读障碍症患者的视觉处理缺陷的作用仍不清楚，并且继续引起争议。迄今为止，大多数研究都使用了字母和/或其他依赖语言的模式。本研究比较了阅读障碍症患者和正常读者如何处理非字母视觉模式。
刺激物是黑白画，有 50 个有意义的（具体对象）和 50 个无意义的（没有语言名称的伪对象），在计算机屏幕上以视觉方式呈现。测量包括行为准确性和反应时间、事件相关电位（ERP）和低分辨率电磁断层扫描（LORETA）。受试者为 15 名阅读障碍症患者和 15 名年龄匹配的正常读者。
阅读障碍症患者对物体和伪对象的反应时间明显长于正常读者，P1 和 P2 成分的潜伏期也明显短于正常读者。来自 LORETA 解决方案分析的数据表明，两组之间的大脑活动明显不同：两组在观看物体时都表现出左半球激活更高，而观看伪对象时则较低；阅读障碍症患者在观看物体时左半球激活较低，观看伪对象时右半球激活较高，这发生在处理的早期阶段。
结果支持这样一种观点，即阅读障碍症患者的大脑激活在处理非字母模式时与正常读者不同，并且差异出现在处理的早期阶段。
这些结果强调，即使在非字母任务中，也可以看到阅读障碍症患者和正常读者之间大脑活动的差异，并且这种差异出现在处理的早期阶段。
