Querner Veronika, Krafczyk Siegbert, Dieterich Marianne, Brandt Thomas
Department of Neurology, Ludwig-Maximilians-University, Klinikum Grosshadern, Marchioninistr. 15, 81377 Munich, Germany.
Exp Brain Res. 2002 Apr;143(3):269-75. doi: 10.1007/s00221-001-0955-y. Epub 2002 Feb 9.
Patients with phobic postural vertigo (PPV) often report a particularly increased unsteadiness when looking at moving visual scenes. Therefore, the differential effects of large-field visual motion stimulation in roll plane on body sway during upright stance were analyzed in 23 patients with PPV, who had been selected for the integrity of their vestibular and balance systems, and in 17 healthy subjects. Visual motion stimulation induced a sensation of apparent body motion (roll vection) in all patients and normal subjects. Normal subjects showed an increased lateral sway path with a lateral shift of the center of pressure (COP) in stimulus direction (mean 1.67 cm, SD 1.63). The patients also exhibited an increase in sway path during visual motion stimulation; however, their body sway differed from that of normals in that there was no lateral displacement of COP (mean 0.19 cm, SD 0.73). The lateral displacement of COP and the increase in RMS of body sway during visual motion stimulation were significantly greater in normals than in the patients ( p<0.05). The patients' increased body sway without COP deviation does not imply an increased risk of falling. Two explanations are conceivable for this increased body sway without body deviation in patients with PPV: (a) the patients rely more on proprioceptive and vestibular rather than on visual cues to regulate upright stance; or (b) they depend on visual, vestibular, and proprioceptive information, but the threshold at which they initiate a compensatory body sway opposite in direction to a perceived body deviation is lower than in normal subjects. The data support the second explanation.
患有恐惧性姿势性眩晕（PPV）的患者在观看动态视觉场景时，常常报告特别明显的不稳定感。因此，我们分析了23例PPV患者和17名健康受试者在直立姿势下，横滚平面大视野视觉运动刺激对身体摆动的不同影响。这些PPV患者的前庭和平衡系统功能完整。视觉运动刺激在所有患者和正常受试者中均诱发了明显的身体运动感觉（横滚错觉）。正常受试者在刺激方向上的压力中心（COP）出现侧向偏移，侧向摆动路径增加（平均1.67厘米，标准差1.63）。患者在视觉运动刺激期间的摆动路径也有所增加；然而，他们的身体摆动与正常人不同，因为COP没有侧向位移（平均0.19厘米，标准差0.73）。在视觉运动刺激期间，正常受试者的COP侧向位移和身体摆动均方根（RMS）的增加显著大于患者（p<0.05）。患者身体摆动增加但COP无偏差并不意味着跌倒风险增加。对于PPV患者这种无身体偏差的身体摆动增加，可以想到两种解释：（a）患者更多地依赖本体感觉和前庭感觉而非视觉线索来调节直立姿势；或者（b）他们依赖视觉、前庭和本体感觉信息，但他们启动与感知到的身体偏差方向相反的补偿性身体摆动的阈值低于正常受试者。数据支持第二种解释。
