EFFECT OF VISUAL OCCLUSION AND LIGHT TOUCH ON DYNAMIC POSTURAL BALANCE ON AN UNSTABLE PLATFORM IN ELDERLY AND YOUNG ADULT WOMEN

ABSTRACT Aging causes the detriment of sensory information that reflects the quality of postural control. The use of light touch has been suggested as a strategy to reduce postural sway even in the absence of vision. However, the effects of this strategy in unstable situations on the support base are unclear. The aim of this study was to analyze the effects of visual occlusion and light touch on the balance of elderly and young adult women on an unstable platform. Twenty elderly women (69.4±6.7 years) and twenty young adult women (20.6±3.2years) performed three attempts at the task which consisted of maintaining balance on an unstable platform on a bipedal base for twenty seconds, with medial-lateral perturbation, in four conditions. The Mann-Whitney U test showed that the elderly women presented worse balance compared to the young adult women in all conditions (p<0.05). The Friedman and Wilcoxon tests demonstrated worse balance with visual occlusion in both groups (p<0.05). On the other hand, there was an improvement in balance using light touch for both vision and no vision conditions (p<0.05). Both groups were able to use the haptic sensory information through light touch to assist in balance maintenance.

摘要：衰老会损害反映姿势控制质量的感觉信息。即便在无视觉输入的情况下，轻触（light touch）也被视作一种可降低姿势摆动的策略。然而，该策略在支撑基底不稳定的情境中的应用效果尚不明确。本研究旨在探究视觉遮蔽与轻触对不稳定平台上老年与青年女性平衡能力的影响。

20名老年女性（年龄69.4±6.7岁）与20名青年女性（年龄20.6±3.2岁）在4种实验条件下，各完成3次任务：在施加有内外侧扰动的不稳定平台上，以双足支撑姿势维持平衡20秒。

曼-惠特尼U检验（Mann-Whitney U test）结果显示，所有实验条件下老年女性的平衡能力均显著差于青年女性（p<0.05）。弗里德曼检验（Friedman test）与威尔科克森检验（Wilcoxon test）结果表明，两组受试者在视觉遮蔽状态下的平衡能力均显著下降（p<0.05）。另一方面，无论是否保留视觉输入，采用轻触策略均可显著提升两组的平衡能力（p<0.05）。两组受试者均能通过轻触获取触觉感觉信息，辅助维持身体平衡。