Karnath H O, Christ K, Hartje W
Department of Neurology, Rheinisch-Westfälische Technische Hochschule Aachen, Germany.
Brain. 1993 Apr;116 ( Pt 2):383-96. doi: 10.1093/brain/116.2.383.
Three patients with a right hemisphere lesion and marked left-sided neglect without visual field defects were asked to detect and identify stimuli which were tachistoscopically presented in the left or right visual half-field. Neglect of stimuli presented in the contralesional left visual field, which was observed when the patient's body was in a normal upright position with trunk, head and gaze oriented straight ahead to the middle of the projection screen, could be reduced by vibrating the left posterior neck muscles as well as by turning the trunk 15 degrees to the left. In contrast, unspecific stimulation on the left side of the patient's body, produced by vibrating the left hand muscles or the proprioceptive signal induced by turning the head 15 degrees to the left, had no compensatory effects. The results showed that the afferent information about real lengthening of the left posterior neck muscles (produced by turning the trunk) as apparent lengthening of these muscles (produced by their vibration), leads to a remission of contralateral neglect. Thus, the proprioceptive input from the neck muscles, i.e. the head-on-trunk signal, appears to influence the extension of the neglected part of space in patients with neglect. The signal seems to contribute substantially to the neural generation of the egocentric frame of reference that allows the determination of body position with respect to visual space. We hypothesize that the reduction of neglect by vibration of the contralateral posterior neck muscles is based on a shift of the subjective spatial localization of the sagittal midplane in the contralesional direction and a corresponding alteration of the egocentric coordinate system necessary for visuomotor coordination and exploration of space.
三名右侧半球病变且有明显左侧忽视但无视野缺损的患者被要求检测并识别通过速示器呈现于左或右视野半侧的刺激。当患者身体处于正常直立姿势，躯干、头部和目光直视投影屏幕中间时，观察到对呈现于对侧左视野半侧的刺激存在忽视，而通过振动左后颈部肌肉以及将躯干向左转动15度，这种忽视可得到减轻。相比之下，通过振动左手肌肉或向左转动头部15度所诱发的本体感觉信号对患者身体左侧进行的非特异性刺激则没有代偿作用。结果表明，关于左后颈部肌肉实际拉长（由转动躯干产生）的传入信息作为这些肌肉的明显拉长（由其振动产生），会导致对侧忽视的减轻。因此，来自颈部肌肉的本体感觉输入，即头-躯干信号，似乎会影响忽视患者被忽视空间部分的范围。该信号似乎在很大程度上有助于以自我为中心的参照系的神经生成，从而能够确定身体相对于视觉空间的位置。我们推测，对侧后颈部肌肉振动减轻忽视是基于矢状中平面的主观空间定位向对侧方向的偏移以及对视运动协调和空间探索所需的以自我为中心的坐标系的相应改变。
