Department of Physical Therapy, College of Allied Health Sciences, University of Nevada Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-3029, USA.
J Neurol. 2012 Dec;259(12):2664-72. doi: 10.1007/s00415-012-6566-7. Epub 2012 Jun 29.
We explored how changes in visual attention impacted postural motor performance in healthy elders and adults post-stroke within a virtual reality environment, including when vestibular information was not perceptible. Visual dependence in 13 healthy (50-80 years) and 13 adults post-stroke (49-70 years) was assessed with a rod-and-frame task. Three degree support surface dorsiflexion tilts at 30°/s were combined with 30° and 45°/s continuous pitch rotations of the visual environment. The support surface remained tilted for 30 s followed by a 0.1°/s return to neutral during continued visual field rotation. Body displacement and ankle muscle responses were recorded, and wavelet transforms calculated. Muscle frequencies and kinematic measures were examined with functional principal component analysis, and weights compared through mixed model repeated measures ANOVA. Both populations exhibited increased backward sway with pitch upward visual field motion; adults post-stroke produced significantly larger muscle responses. Lateral sway was most regulated when visual flow velocity matched platform velocity. Visual flow summed with direction of support surface instability and visually dependent individuals produced more controlled lateral sway when viewing a dynamic visual field. Provoking postural instability within a dynamic visual flow field could serve as a training tool for postural stabilizing actions, particularly when visual dependence is exhibited.
我们在虚拟现实环境中探索了视觉注意力的变化如何影响健康老年人和中风后成年人的姿势运动表现，包括在无法感知前庭信息时的情况。使用棒框任务评估了 13 名健康老年人（50-80 岁）和 13 名中风后成年人（49-70 岁）的视觉依赖性。以 30°/s 的速度对 3 度支撑面背屈进行倾斜，同时以 30°和 45°/s 的速度对视觉环境进行连续俯仰旋转。支撑面倾斜 30 秒，然后在视觉场继续旋转的同时以 0.1°/s 的速度返回中立位置。记录身体位移和踝关节肌肉反应，并计算小波变换。使用功能主成分分析检查肌肉频率和运动学测量值，并通过混合模型重复测量方差分析比较权重。两个群体在向上的视觉场运动时都表现出向后的摆动增加；中风后的成年人产生的肌肉反应明显更大。当视觉流速度与平台速度匹配时，侧向摆动最受调节。当视觉流与支撑面不稳定的方向相加，并且视觉依赖的个体在观察动态视觉场时，会产生更受控的侧向摆动。在动态视觉流场中引起姿势不稳定可能成为姿势稳定动作的训练工具，尤其是当表现出视觉依赖时。
