Visual attention in posterior stroke and relations to alexia
Visual attention in posterior stroke and relations to alexia
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后脑卒中的视觉注意力及其与失读症的关系
DOI：
10.1016/j.neuropsychologia.2016.02.029
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发表时间：
2016
期刊：
影响因子：
2.6
通讯作者：
R. Starrfelt
中科院分区：
文献类型：
--
作者：
A. Petersen;S. Vangkilde;C. Fabricius;H. Iversen;T. Delfi;R. Starrfelt
在大脑中动脉区域（尤其是右半球）中风后，视觉注意力受损是常见的，而更多后部病变对注意力的影响则不太清楚。通常，这种缺陷与特定综合征如视觉失认症或纯粹失读症有关。本研究的目的是描述大脑后动脉（PCA）卒中后的视觉处理速度和理解广度。此外，这些注意力参数和单个单词阅读之间的关系进行了调查，因为以前的研究表明，降低视觉速度和广度可以解释纯失读症。根据病变位置，而不是任何视觉症状的存在，选择了8例单侧PCA卒中患者（4例左半球，4例右半球）。视觉注意的特点是由一个整体的报告范式，允许半场特定的测量处理速度和理解广度。所有患者均显示病变部位对侧的视力缩短，4例患者显示双侧视力缩短，尽管单侧病变（2L; 2 R）。六名患者表现出视觉广度的选择性缺陷，尽管同一视野（同侧或对侧）的处理速度不受影响。只有右侧视野缩小的患者阅读受损，这可能是右侧或左侧卒中所致，与视野受损无关。总之，视觉广度可能会受到影响，双边的单侧PCA病变。视觉广度的减少也可能局限于一个半视野，尽管保留了视觉处理速度，但可能会受到影响。此外，无论病变是否偏侧，右视野范围缩小似乎与该组的阅读障碍有关。
Impaired visual attention is common following strokes in the territory of the middle cerebral artery, particularly in the right hemisphere, while attentional effects of more posterior lesions are less clear. Commonly, such deficits are investigated in relation to specific syndromes like visual agnosia or pure alexia. The aim of this study was to characterize visual processing speed and apprehension span following posterior cerebral artery (PCA) stroke. In addition, the relationship between these attentional parameters and single word reading is investigated, as previous studies have suggested that reduced visual speed and span may explain pure alexia. Eight patients with unilateral PCA strokes (four left hemisphere, four right hemisphere) were selected on the basis of lesion location, rather than the presence of any visual symptoms. Visual attention was characterized by a whole report paradigm allowing for hemifield-specific measurements of processing speed and apprehension span. All patients showed reductions in visual span contralateral to the lesion site, and four patients showed bilateral reductions in visual span despite unilateral lesions (2L; 2R). Six patients showed selective deficits in visual span, though processing speed was unaffected in the same field (ipsi- or contralesionally). Only patients with right hemifield reductions in visual span were impaired in reading, and this could follow either right or left lateralized stroke and was irrespective of visual field impairments. In conclusion, visual span may be affected bilaterally by unilateral PCA-lesions. Reductions in visual span may also be confined to one hemifield, and may be affected in spite of preserved visual processing speed. Furthermore, reduced span in the right visual field seems to be related to reading impairment in this group, regardless of lesion lateralization.