脑卒中患者偏侧忽略线分法试验中线段位置对结果的影响

The effects of line location in the line bisection test

目的研究线分法试验中线段位置对不同程度偏侧忽略脑卒中患者线分结果的影响，探讨线段位置对线分结果影响的机制。方法根据凯瑟林一波哥量表（CatherineBergegoScale，CBS）检出26例首发脑卒中致左侧偏侧忽略的患者，分为轻度忽略组（15例）和重度忽略组（11例），20例年龄匹配的健康成人作为对照组。进行线分法检查时，让患者中分在Ag纸的左侧、中央和右侧的长度为10cm的水平线段。然后在另外一张同样的Ag纸上，先让患者标出他所看到的线段两端，然后再在标出的线段中央划一条垂直分隔线。计算分隔线右侧长度占所分隔线段长度的百分比。结果轻度忽略组与对照组在上述线分试验中所有结果的差异均无统计学意义。在标出线段两端前，重度忽略组患者分隔左侧及中央线段时分隔线较实际中点出现明显右移。重度忽略患者标记后的3条线段长度均明显短于对照组和轻度忽略组，缩短的原因是标记左侧端点时标记点明显右移。结论线段位置主要对重度偏侧忽略患者的线分结果有影响，其主要机制是重度偏侧忽略患者所看到的线段均较实际线段短，忽略了所有位置线段的左侧端，这种忽略程度白左向右逐渐减轻。

Objective To investigate the effects of line location on the results of the line bisection test and the mechanism behind these effects. Methods Twenty-six first time stroke patients with left hemiparesis who were evaluated as having unilateral neglect according to the Catherine Bergego scale （CBS） were divided into 2 groups： a mild unilateral neglect group and a severe group. Twenty healthy subjects served as age-matched control subjects. In a line bisection test, three 10cm long lines were presented on the left, middle and right of an A4 sheet of paper. The subjects were asked to place a short cross mark at the exact midpoint of each line using their right hand. They were then presented with an identical set of three lines on a fresh sheet of paper and asked this time to first mark the two ends of each line before marking the midpoints. Each attempt was scored by calculating the proportion of the right portion to the total line length. Results There were no significant differences between patients with mild unilateral neglect and controls in their performance on any of these bisection tests. Before marking the line endings, patients with severe unilateral neglect showed distinct right deviation in bisecting the left-and right-hand lines. The differences when compared with controls and patients with mild unilateral neglect were highly significant. After marking the line endings, all marking by patients with severe unilateral neglect moved significantly to the right, because their left ending markings deviated to the right of the exact left endings. When bisecting lines with marked ends, obvious right deviation was still seen in patients with severe unilateral neglect. Conclusion An effect of line location on the results of the line bisection test was seen only in patients with severe unilateral neglect （by CBS score）. The main mechanism of this location effect is that such patients see the length for bisecting as shorter than it really is. This is because the patients＇ neglect of the left part of the line and the extent of neglect decreases from left to right.