Konczak J, Karnath H O
Department of Neurology, University of Tübingen, Tübingen, Germany.
Brain Cogn. 1998 Aug;37(3):387-403. doi: 10.1006/brcg.1998.1004.
Do patients with unilateral neglect exhibit direction-specific deficits in the control of movement velocity when performing goal-directed arm movements? Five patients with left-sided neglect performed unrestrained three-dimensional pointing movements to visual targets presented at body midline, the left and right hemispace. A group of healthy adults and a group of patients with right-hemispheric brain damage but no neglect served as controls. Pointing was performed under normal room light or in darkness. Time-position data of the hand were recorded with an opto-electronic camera system. We found that compared to healthy controls, movement times were longer in both patient groups due to prolonged acceleration and deceleration phases. Tangential peak hand velocity was lower in both patient groups, but not significantly different from controls. Single peak, bell-shaped velocity profiles of the hand were preserved in all right hemispheric patients and in three out of five neglect patients. Most important, the velocity profiles of neglect patients to leftward targets did not differ significantly from those to targets in the right hemispace. In summary, we found evidence for general bradykinesia in neglect patients, but not for a direction-specific deficit in the control of hand velocity. We conclude that visual neglect induces characteristic changes in exploratory behavior, but not in the kinematics of goal-directed movements to objects in peripersonal space.
单侧忽视患者在进行目标导向的手臂运动时，在运动速度控制方面是否存在特定方向的缺陷？五名左侧忽视患者对位于身体中线、左半空间和右半空间的视觉目标进行了无约束的三维指向运动。一组健康成年人和一组右侧半球脑损伤但无忽视症状的患者作为对照组。指向运动在正常室内光线或黑暗条件下进行。使用光电摄像系统记录手部的时间-位置数据。我们发现，与健康对照组相比，由于加速和减速阶段延长，两个患者组的运动时间都更长。两个患者组的切向峰值手部速度都较低，但与对照组无显著差异。所有右侧半球患者和五名忽视患者中的三名保留了单峰、钟形的手部速度曲线。最重要的是，忽视患者对向左目标的速度曲线与对右半空间目标的速度曲线没有显著差异。总之，我们发现了忽视患者存在一般性运动迟缓的证据，但没有发现手部速度控制存在特定方向缺陷的证据。我们得出结论，视觉忽视会引起探索行为的特征性变化，但不会引起对个人周边空间中物体的目标导向运动的运动学变化。
