IntroductionPlantar cutaneous augmentation is a promising approach in balance rehabilitation by enhancing motion-dependent sensory feedback. The effect of plantar cutaneous augmentation on balance has been mainly investigated in its passive form (e.g., textured insole) or on lower-limb amputees. In this study, we tested the effect of plantar cutaneous augmentation on balance in its active form (i.e., electrical stimulation) for individuals with intact limbs.MethodsTen healthy subjects participated in the study and were instructed to maintain their balance as long as possible on the balance board, with or without electrotactile feedback evoked on the medial side of the heel, synched with the lateral board sway. Electrotactile feedback was given in two different modes: 1) Discrete-mode E-stim as the stimulation on/off by a predefined threshold of lateral board sway and 2) Proportional-mode E-stim as the stimulation frequency proportional to the amount of lateral board sway. All subjects were distracted from the balancing task by the n-back counting task, to test subjects’ balancing capability with minimal cognitive involvement.ResultsProportional-mode E-stim, along with the n-back counting task, increased the balance time from 1.86 ± 0.03 s to 1.98 ± 0.04 s (p = 0.010). However, discrete-mode E-stim did not change the balance time (p = 0.669). Proportional-mode E-stim also increased the time duration per each swayed state (p = 0.035) while discrete-mode E-stim did not (p = 0.053).DiscussionThese results suggest that proportional-mode E-stim is more effective than discrete-mode E-stim on improving standing balance. It is perhaps because the proportional electrotactile feedback better mimics the natural tactile sensation of foot pressure than its discrete counterpart.

中文翻译：

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基于比例摇摆的电触觉反馈可改善横向站立平衡

简介通过增强运动依赖性的感觉反馈，足底皮肤增强是平衡康复中一种有前途的方法。足底皮肤增强对平衡的影响主要以其被动形式（例如纹理鞋垫）或下肢截肢者的形式进行研究。在这项研究中，我们测试了足底皮肤增强术对肢体完整的个体的主动形式（即电刺激）平衡的影响。方法十名健康受试者参与了这项研究，并被指示在地面上尽可能长时间地保持平衡。平衡板，有或没有在脚跟内侧引起的电触觉反馈，与外侧板摇摆同步。电触觉反馈以两种不同的模式给出：1) 离散模式 E-stim 作为通过侧向板摇摆的预定义阈值打开/关闭的刺激；2) 比例模式 E-stim 作为与侧向板摇摆量成比例的刺激频率板摇摆。所有受试者都通过 n 回计数任务分散了对平衡任务的注意力，以在最少的认知参与下测试受试者的平衡能力。结果比例模式 E-stim 与 n 回计数任务一起，将平衡时间从 1.86 ± 增加了0.03 秒至 1.98 ± 0.04 秒（p= 0.010）。然而，离散模式 E-stim 并没有改变平衡时间（p= 0.669）。比例模式电子刺激还增加了每个摇摆状态的持续时间（p= 0.035），而离散模式 E-stim 则没有（p= 0.053）。讨论这些结果表明，比例模式 E-stim 在改善站立平衡方面比离散模式 E-stim 更有效。这可能是因为比例电触觉反馈比离散电触觉反馈更好地模拟了足部压力的自然触觉。