Approaches to subjective midpoint of horizontal lines in unilateral spatial neglect
Approaches to subjective midpoint of horizontal lines in unilateral spatial neglect
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DOI：
10.1016/s0010-9452(08)70405-2
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发表时间：
2006-07-01
期刊：
影响因子：
3.6
通讯作者：
Izumi, Yorimichi
中科院分区：
文献类型：
--
作者：
Ishiai, Sumio;Koyama, Yasumasa;Izumi, Yorimichi
单侧空间忽略的患者通常平分较长的线，具有较大的重复错误，而他们有时会错误地平分非常短的线（例如，25毫米）。我们分析了运动的眼睛注视线演示前的时间，以阐明是否忽视患者的方法不同的主观中点的不同长度的线。四名左忽视患者平分200毫米，100毫米，25毫米的线，出现在液晶显示器（LCD）显示器的中心。线呈现前的注视平均位于线的中心附近。在超过70%的200 mm和100 mm试验中，3名患者直接从左侧接近主观中点。主观中点在最左侧注视点和右侧注视点之间的“关注”节段上经常偏离10 °，而在整个范围上移位10 °。三名患者最初探索了25 mm线，以寻找左端点。之后，他们将同样的线一分为二，从左侧接近主观中点的误差为10%。其余患者在右侧终点之外搜索，然后在约一半的试验中从右侧接近主观中点，并且与线长度无关。在200 mm和100 mm试验中，主观中点将参与的右节段划分为更接近右终点。在一条线的关注范围内，忽视患者可能会将主观中点置于他们接近该点的一侧。在很短的直线的二等分中，从左端点接近可能会导致主观中点的极大误差。然而，对于较长的线，从左侧的方法可能会导致对分的总长度的错误，因为几乎没有探索线呈现之前的注视的范围。
Patients with unilateral spatial neglect usually bisect longer lines with greater rightward errors, while they sometimes err leftward for very short lines (e.g., 25 mm). We analysed movements of eye fixation from the time before line presentation to elucidate whether patients with neglect approach the subjective midpoint differently for lines of various lengths. Four patients with left neglect bisected 200 mm, 100 mm, and 25 mm lines that appeared across the centre of a liquid crystal display (LCD) monitor. The fixation immediately before line presentation was located on average near the centre of the lines. Three of the patients approached the subjective midpoint point directly from the left side in more than 70% of the 200 mm and 100 mm trials. The subjective midpoint frequently deviated leftward on the "attended" segment between the leftmost point of fixation and the right endpoint, while it was displaced rightward on the total extent. The three patients initially explored the 25 mm lines searching for the left endpoint. They thereafter bisected the same lines with leftward errors approaching the subjective midpoint from the left side. The remaining patient searched beyond the right endpoint and in turn approached the subjective midpoint from the right side in about half of the trials and independently of line length. In the 200 mm and 100 mm trials, the subjective midpoint divided the attended right segment nearer to the right endpoint. On the attended fight extent of a line, patients with neglect may place the subjective midpoint toward the side from which they approached that point. In the bisection of very short lines, approaches from the left endpoint may cause leftward errors of the subjective midpoint. For longer lines, however, approaches from the left side may result in rightward error of bisection for the total length, as the leftward extent from the fixation immediately before line presentation is hardly explored.