Visual processing and dyslexia
Visual processing and dyslexia
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DOI：
10.1068/p2743
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发表时间：
1999-01-01
期刊：
影响因子：
1.7
通讯作者：
Hibbard, PB
中科院分区：
文献类型：
--
作者：
Everett, J;Bradshaw, MF;Hibbard, PB
大细胞通路缺陷被认为是造成阅读障碍者在阅读中出现问题的原因。然而，研究尚未提供这些缺陷的后果的详细说明或确定它们与阅读障碍之间的行为联系。本研究的目的是确定阅读障碍者在一系列视觉任务中大细胞通路缺陷的潜在后果。阅读障碍者和非阅读障碍者的能力进行了比较：（一）执行游标敏锐度和方向敏锐度任务;（二）通过使用一系列常见的心理物理学文献中的措施（D-最小值，D-最大值，和全球的一致性）感知运动;（三）感知形状的随机点立体图在一系列的视差距离，从而分离的立体视觉聚散控制。结果表明，在视觉敏锐度的措施方面，没有显着差异的表现之间的障碍和nondyslephilis主题。在一般情况下，诵读困难的表现相对较差的运动知觉和立体视觉的措施，虽然当单独考虑一些诵读困难的表现优于一些控制。阅读障碍者在立体图任务中的表现不佳是由于阅读障碍者中的一个亚组也出现了严重的运动连贯性任务困难。这些数据是一致的，与以前的证据表明，一些诵读困难可能有缺陷的magnocellular视觉通路。
Magnocellular-pathway deficits have been hypothesised to be responsible for the problems experienced by dyslexic individuals in reading. However, research has yet to provide a detailed account of the consequences of these deficits or to identify the behavioural link between them and reading disabilities. The aim of the present study was to determine the potential consequences of the magnocellular-pathway deficits for dyslexics in a comprehensive range of visual tasks. Dyslexics and nondyslexics were compared on their ability to (i) perform vernier-acuity and orientation-acuity tasks; (ii) perceive motion by using a range of measures common in the psychophysical literature (D-min, D-max, and global coherence); and (iii) perceive shapes presented in random-dot stereograms at a range of disparity pedestals, thereby dissociating stereopsis from vergence control. The results indicated no significant differences in performance between the dyslexic and nondyslexic subjects in terms of the visual-acuity measures. In general, dyslexics performed relatively poorly on measures of motion perception and stereopsis, although when considered individually some of the dyslexics performed better than some of the controls. The poor performance of the dyslexics in the stereogram tasks was attributable to a subgroup of dyslexics who also appeared to have severe difficulty with the motion-coherence task. These data are consistent with previous evidence that some dyslexics may have deficits within the magnocellular visual pathway.