MECHANISMS AND REHABILITATION OF UNILATERAL SPATIAL NEGLECT : ANALYSIS OF INTERACTION BETWEEN ATTENTION AND MOTOR EXECUTION

本研究旨在阐明右脑损伤后导致单侧空间忽略的注意-表征机制和运动机制，并开发对忽视的诊断和康复技术。在对称定位任务中，向左侧忽略患者展示一张印有中央竖条和右侧小圆圈的测试纸。他们被要求在左侧的水平对称点上标记一个圆圈。通过眼球和手的运动记录和分析，探讨忽视中知觉和运动交互作用的特点。当这种交叉反应被要求进入对侧空间时，该空间的表征图也可能在忽视患者的大脑中被激活。此外，准备向左反应可能会导致眼睛和手有效地定向到左侧空间，这在普通刺激-反应兼容条件下是很难探索的。即使在涉及右顶叶的病变之后发生左忽视，完全感知的线条的图像也可以表现在足够远的左侧空间中。然而，在估计表象上的主观中点时，可能会出现左忽视现象，这可能是由于注意分布的右倾。该系统能够分析时间进程和空间扫描，并提供详细的信息，以提高对轻微疏忽造成的问题的检测。

The present study aimed to elucidate the attentional-representational and motor mechanisms that cause unilateral spatial neglect after right hemisphere damage and to develop diagnostic and rehabilitation technique for neglect.In the symmetric positioning task, patients with left neglect were presented with a test sheet where a central vertical bar and a right small circle were printed. They were required to mark a circle at the horizontally symmetric point on the left side. The movements of the eyes and the hand were recorded and analyzed to explore the characteristics of perceptual and motor interaction in neglect. When such a crossed response is required into contralesional space, the representational map for that space may be activated also in the brain of patients with neglect. Besides, preparation of a leftward response may result in an effective orientation of the eyes and the hand into the left space, which would be hardly explored in the ordinary stimulus-response compatible condition.A line image task using a computer display with a touch panel was devised to explore representational image for lines when patients with neglect were asked to touch the left endpoint and perceived the whole extent reliably. The image for a fully perceived line may be represented far enough into left space even when left neglect occurs after a lesion that involves the right parietal lobe. However, left neglect may occur in estimation of the subjective midpoint on the representational image, which may be explained by a rightward bias of attentional distribution.A system with personal computer and cordless tablet was introduced to record performances of patients with neglect in the Behavioral inattention test (BIT, PC version). This system enabled analysis of time course and spatial scanning and gave detailed information to improve detection of problems due to mild neglect.