Influences of the visual perturbation upon body stability

在前庭障碍患者中，身体稳定性受到视觉条件的影响。身体摇摆不仅可能由于视觉信息的完全丢失而增加，而且可能由于视觉扰动而增加，例如汽车就在患者旁边不可预测地经过。本研究探讨了视觉扰动对静态和动态身体平衡的影响。本研究采用恒定速度视动刺激作为视觉扰动，视动刺激的视觉目标为条纹图案和随机点图案。视觉扰动引起的不稳定性与闭眼状态下的身体稳定性基本一致。对周边视野的刺激越强，对身体稳定性的影响越大，即不稳定性增加.由于部分单侧前庭障碍患者的身体平衡受视觉干扰的影响较大，在日常生活中应给予指导，防止意外跌倒.虽然有半数健康志愿者左右足的力量存在差异，表明在扰动引起的不平衡后恢复到原来的速度，但视动刺激无方向特异性。

In patients with vestibular disorders the body stability is influenced by visual conditions. The body sway might increase not only by complete loss of the visual information but also by the visual perturbation such as unpredictable pass of a car just beside a patient. In this research we investigated about the influence of the visual perturbation upon the static and dynamic body balance. Constant velocity optokinetic stimulation, the visual targets of which were a stripe pattern and a random dot pattern, were used as visual perturbation in this study.The results is summarized as follows :1. The unsteadiness caused by the visual perturbation was almost same as the body stability under the eyes closed condition. The stronger stimulation to the peripheral visual field more influenced to the body stability, i.e.the unsteadiness increased.2. Becaouse the body balance of some patients with unilateral vestibular disorders more affected by the visual perturbation, it should be necessary to guide to protect from unpredictable fall in daily life.3. Altough difference of strength between the left and righ foot, which indicated velocity until to get recovery after the unbalance caused by the perturbation, was observed half of healthy volunteers, there was no directional specificity by the optokinetic stimulation.