Academic Department of Physiotherapy, School of Biomedical Sciences, Centre for Human and Aerospace Physiology, Kings College London, London, United Kingdom.
Gait Posture. 2011 Jan;33(1):113-8. doi: 10.1016/j.gaitpost.2010.10.085. Epub 2010 Dec 8.
Patients with vestibular dysfunction, migraine and/or anxiety may experience visual vertigo (VV), whereby symptoms are provoked by disorienting visual environments (e.g. supermarkets). Patients with VV over rely on vision for balance (i.e. visually dependent). Visual vertigo significantly improves when vestibular rehabilitation incorporates exposure to optokinetic stimulation (OKS). However, whether OKS exposure induces a reduction in visual dependency is unknown. This study investigated this issue by measuring visual dependency before and after repeated OKS exposure. Twenty-six healthy subjects (10 males; mean age 29.8 years, range 20-42 years) were randomly allocated into an OKS group who underwent graded OKS exposure for five consecutive days, or a no intervention control group. Assessment included the 'Rod and Frame' and 'Rod and Disc' tests where subjects set the subjective visual vertical in darkness, facing a tilted luminous frame or luminous rotating disc, respectively. Postural sway measures were obtained with eyes open, closed and facing the rotating disc. Results showed significant reductions in subjective vertical tilt with the frame and rotating disc for the OKS group only (p≤0.01). Total sway path and mean deviation induced by the rotating stimulus decreased significantly only for the OKS group (p<0.01), as did the Kinetic Quotient (disc rotation/eyes open sway path ratio; p=0.04). The Romberg Quotient (eyes closed/eyes open ratio) showed no change. Findings suggest visual dependency, both at a perceptual and a postural level, can be reduced with short-term graded OKS exposure in healthy subjects. This has important implications for treatment of patients with VV and balance disorders.
患有前庭功能障碍、偏头痛和/或焦虑症的患者可能会出现视觉性眩晕（VV），其症状由使人迷失方向的视觉环境引起（例如超市）。患有 VV 的患者过度依赖视觉来维持平衡（即视觉依赖性）。前庭康复结合视动刺激（OKS）可显著改善 VV。然而，OKS 暴露是否会降低视觉依赖性尚不清楚。本研究通过测量重复 OKS 暴露前后的视觉依赖性来研究这个问题。26 名健康受试者（10 名男性；平均年龄 29.8 岁，范围 20-42 岁）被随机分配到 OKS 组和无干预对照组。评估包括“棒框测试”和“棒碟测试”，受试者在黑暗中分别面对倾斜的发光框或旋转的发光盘来设置主观垂直视觉。睁眼、闭眼和面对旋转盘时，获取姿势摆动测量值。结果显示，只有 OKS 组的框架和旋转盘的主观垂直倾斜显著减小（p≤0.01）。只有 OKS 组的总摆动路径和旋转刺激引起的平均偏差显著减小（p<0.01），运动觉商（旋转盘/睁眼摆动路径比；p=0.04）也减小。Romberg 商（闭眼/睁眼比）没有变化。研究结果表明，在健康受试者中，短期分级 OKS 暴露可降低知觉和姿势水平的视觉依赖性。这对治疗 VV 和平衡障碍患者具有重要意义。
