Pérennou D A, Mazibrada G, Chauvineau V, Greenwood R, Rothwell J, Gresty M A, Bronstein A M
Clinique de Médecine Physique et Réadaptation, Hôpital Nord-CHU Grenoble, Université Grenoble 1 degrees, Unité de Rééducation Neurologique du Grau du Roi, CHU Nîmes, France.
Brain. 2008 Sep;131(Pt 9):2401-13. doi: 10.1093/brain/awn170. Epub 2008 Aug 4.
The relationships between perception of verticality by different sensory modalities, lateropulsion and pushing behaviour and lesion location were investigated in 86 patients with a first stroke. Participants sat restrained in a drum-like framework facing along the axis of rotation. They gave estimates of their subjective postural vertical by signalling the point of feeling upright during slow drum rotation which tilted them rightwards-leftwards. The subjective visual vertical was indicated by setting a line to upright on a computer screen. The haptic vertical was assessed in darkness by manually setting a rod to the upright. Normal estimates ranged from -2.5 degrees to 2.5 degrees for visual vertical and postural vertical, and from -4.5 degrees to 4.5 degrees for haptic vertical. Of six patients with brainstem stroke and ipsilesional lateropulsion only one had an abnormal ipsilesional postural vertical tilt (6 degrees ); six had an ipsilesional visual vertical tilt (13 +/-.4 degrees ); two had ipsilesional haptic vertical tilts of 6 degrees . In 80 patients with a hemisphere stroke (35 with contralesional lateropulsion including 6 'pushers'), 34 had an abnormal contralesional postural vertical tilt (average -8.5 +/- 4.7 degrees ), 44 had contralesional visual vertical tilts (average -7 +/- 3.2 degrees ) and 26 patients had contralesional haptic vertical tilts (-7.8 +/- 2.8 degrees ); none had ipsilesional haptic vertical or postural vertical tilts. Twenty-one (26%) showed no tilt of any modality, 41 (52%) one or two abnormal modality(ies) and 18 (22%) a transmodal contralesional tilt (i.e. PV + VV + HV). Postural vertical was more tilted in right than in left hemisphere strokes and specifically biased by damage to neural circuits centred around the primary somatosensory cortex and thalamus. This shows that thalamo-parietal projections have a functional role in the processing of the somaesthetic graviceptive information. Tilts of the postural vertical were more closely related to postural disorders than tilts of the visual vertical. All patients with a transmodal tilt showed a severe lateropulsion and 17/18 a right hemisphere stroke. This indicates that the right hemisphere plays a key role in the elaboration of an internal model of verticality, and in the control of body orientation with respect to gravity. Patients with a 'pushing' behaviour showed a transmodal tilt of verticality perception and a severe postural vertical tilt. We suggest that pushing is a postural behaviour that leads patients to align their erect posture with an erroneous reference of verticality.
在86例首次发生中风的患者中，研究了不同感觉模态对垂直方向的感知、偏侧推挤和推挤行为与病变位置之间的关系。参与者被固定在一个鼓状框架中，沿旋转轴方向就座。在缓慢的鼓状旋转过程中，鼓向左右倾斜，参与者通过发出感觉直立的点的信号来估计他们主观的姿势垂直方向。主观视觉垂直方向通过在电脑屏幕上设置一条垂直线来表示。在黑暗中通过手动将一根杆设置为垂直来评估触觉垂直方向。视觉垂直方向和姿势垂直方向的正常估计范围为-2.5度至2.5度，触觉垂直方向的正常估计范围为-4.5度至4.5度。在6例脑干中风且有同侧偏侧推挤的患者中，只有1例同侧姿势垂直方向倾斜异常（6度）；6例有同侧视觉垂直方向倾斜（13±0.4度）；2例有同侧触觉垂直方向倾斜6度。在80例半球中风患者中（35例有对侧偏侧推挤，包括6例“推挤者”），34例有对侧姿势垂直方向倾斜异常（平均-8.5±4.7度），44例有对侧视觉垂直方向倾斜（平均-7±3.2度），26例患者有对侧触觉垂直方向倾斜（-7.8±2.8度）；无一例有同侧触觉垂直方向或姿势垂直方向倾斜。21例（26%）在任何模态下均无倾斜，41例（52%）有一或两种模态异常，18例（22%）有跨模态对侧倾斜（即姿势垂直方向+视觉垂直方向+触觉垂直方向）。右半球中风时姿势垂直方向的倾斜比左半球中风时更明显，并且特别受到以初级体感皮层和丘脑为中心的神经回路损伤的影响。这表明丘脑-顶叶投射在躯体感觉重力感受信息的处理中具有功能作用。姿势垂直方向的倾斜比视觉垂直方向的倾斜与姿势障碍的关系更密切。所有有跨模态倾斜的患者均表现出严重的偏侧推挤，18例中有17例为右半球中风。这表明右半球在垂直方向内部模型的构建以及相对于重力的身体定向控制中起关键作用。有“推挤”行为的患者表现出垂直方向感知的跨模态倾斜和严重的姿势垂直方向倾斜。我们认为推挤是一种姿势行为，它导致患者将其直立姿势与错误的垂直参考对齐。
