Tegnér R, Levander M
Department of Neurology, Karolinska Hospital, Stockholm, Sweden.
J Neurol Neurosurg Psychiatry. 1991 Oct;54(10):882-7. doi: 10.1136/jnnp.54.10.882.
Twenty five patients with right cerebral hemisphere damage and neglect participated in a series of bisection experiments. As expected, long lines were bisected to the right of true midpoint. By contrast, large circles and long white paper strips were bisected accurately, or with leftward errors. Small objects were less sensitive to stimulus properties: short lines and paper strips, and small circles, were bisected to the left of true midpoint, and these leftward errors were equally common as rightward errors with long lines. When asked to draw a perpendicular line of the same length as the presented horizontal line, patients overestimated the length of short lines but underestimated that of long lines. Presenting lines in near and far extrapersonal space selectively affected bisection of short lines. The results suggest that two opposing, independent mechanisms determine bisection performance in left neglect.
25名患有右脑半球损伤和偏侧忽视的患者参与了一系列二等分实验。正如预期的那样，长线被二等分在真正中点的右侧。相比之下，大圆圈和长纸条被准确地二等分，或者出现向左的误差。小物体对刺激属性不太敏感：短线和纸条以及小圆圈被二等分在真正中点的左侧，并且这些向左的误差与长线的向右误差同样常见。当被要求画出与呈现的水平线长度相同的垂直线时，患者高估了短线的长度但低估了长线的长度。在近和远的个人空间外呈现线条会选择性地影响短线的二等分。结果表明，两种相反的、独立的机制决定了左侧忽视中的二等分表现。
