Study of Vestibular Maladaptation under Visual-vestibular Conflict

1. 戴水平倒转护目镜行走会引起明显的晕动病，其严重程度不仅受个人易感性的影响，还受周围环境的影响。此外，晕动病的发病常伴有平衡性共济失调。相反，既然垂直方向的视觉反转不会引起晕动病，那么我们必须说，视觉和前庭输入之间的不匹配本身不会引起晕动病，但由于感觉输入不匹配而导致的空间方向检测失败会产生晕动病。为了客观地显示运动病发生时平衡性共济失调，我们对正常人进行了格雷贝尔共济失调测试电池测试，分别在戴上护目镜前、戴上护目镜行走时和行走结束后。在水平反视的情况下，得分显著下降。然而，平衡性共济失调的程度与自主神经症状的严重程度无关。两例双侧迷路丢失的患者，一个是先天性的，另一个是获得性的，用同样的方法检查。虽然这两名患者同样没有表现出晕车症状，但他们表现出截然不同的运动模式和平衡性共济失调。而先天性内耳畸形的病人却能很好地行走。即使戴着水平倒转护目镜，另一个病人。由于链霉素中毒而丧失迷路功能的患者在两种情况下均出现中度至重度共济失调，特别是在佩戴水平倒车护目镜时。基于这些结果，我们提出了一个新的前庭系统自上而下调节的假设，即“空间坐标假说”。

1. Walking while wearing horizontally reversing goggles induced apparent motion sickness, which severity was affected not only by individual susceptibility, but also by surrounding situations. In addition, onset of motion sickness was often accompanied with equilibrium ataxia.2. Since vertically reversed vision, in contrast, did not evoke motion sickness, we must say that a mismatch between visual and vestibular inputs-alone does not evoke motion sickness, but a failure to detect spatial orientation which resulted from mismatched sensory inputs produced motion sickness.3. To objectively show equilibrium ataxia when motion sickness occurred, we examined normal subjects with Graybiel's ataxia test battery, before putting on the goggles, during walking while wearing the goggles and after finishing walking. A significant decrease in the score was found in the case of horizontally reversed vision. However, the degree of equilibrium ataxia did not correlate with the severity of autonomic nervous symptoms.4. Two patients with bilateral labyrinthine loss, one congenital, the other acquired, were examined in the same way. Although both patients similarly did not exhibit motion sickness symptoms, they showed quite different patterns of locomotion and equilibrium ataxia. Whereas a patient with congenital inner ear anomalies could walk well. even while wearing horizontally reversing goggles, the other patient. who lost labyrinthine functions due to Streptomycin intoxication presented moderate to severe ataxia under both situations, especially under wearing horizontally reversing goggles. Based on all these results, we devised, a new hypothesis which infers top-down regulation of the vestibular system called "Spatial Coordinates Hypothesis".