BACKGROUND Establishing gait symmetry is a major aim of amputee rehabilitation and may be more attainable with powered prostheses. Though, based on previous work, we postulate that users transfer a previously-learned motor pattern across devices, limiting the functionality of more advanced prostheses. The objective of this study was to preliminarily investigate the effect of increased stance time via visual feedback on amputees' gait symmetry using powered and passive knee prostheses. METHODS Five individuals with transfemoral amputation or knee disarticulation walked at their self-selected speed on a treadmill. Visual feedback was used to promote an increase in the amputated-limb stance time. Individuals were fit with a commercially-available powered prosthesis by a certified prosthetist and practiced walking during a prior visit. The same protocol was completed with a passive knee and powered knee prosthesis on separate days. We used repeated-measures, two-way ANOVA (alpha = 0.05) to test for significant effects of the feedback and device factors. Our main outcome measures were stance time asymmetry, peak anterior-posterior ground reaction forces, and peak anterior propulsion asymmetry. RESULTS Increasing the amputated-limb stance time via visual feedback significantly improved the stance time symmetry (p = 0.012) and peak propulsion symmetry (p = 0.036) of individuals walking with both prostheses. With the powered knee prosthesis, the highest feedback target elicited 36% improvement in stance time symmetry, 22% increase in prosthesis-side peak propulsion, and 47% improvement in peak propulsion symmetry compared to a no feedback condition. The changes with feedback were not different with the passive prosthesis, and the main effects of device/ prosthesis type were not statistically different. However, subject by device interactions were significant, indicating individuals did not respond consistently with each device (e.g. prosthesis-side propulsion remained comparable to or was greater with the powered versus passive prosthesis for different subjects). Overall, prosthesis-side peak propulsion averaged across conditions was 31% greater with the powered prosthesis and peak propulsion asymmetry improved by 48% with the powered prosthesis. CONCLUSIONS Increasing prosthesis-side stance time via visual feedback favorably improved individuals' temporal and propulsive symmetry. The powered prosthesis commonly enabled greater propulsion, but individuals adapted to each device with varying behavior, requiring further investigation.

中文翻译：

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通过视觉反馈延长动力膝关节假体站立时间对单侧截肢者步态对称性的影响：初步研究。

背景技术建立步态对称性是截肢者康复的主要目标，并且通过动力假肢可能更容易实现。不过，根据之前的工作，我们假设用户在设备之间转移先前学习的运动模式，从而限制了更先进假肢的功能。本研究的目的是初步研究通过视觉反馈增加站立时间对使用动力和被动膝关节假肢的截肢者步态对称性的影响。方法 五名经股骨截肢或膝关节离断的患者以自己选择的速度在跑步机上行走。视觉反馈用于促进截肢站立时间的增加。个人由经过认证的假肢师安装了商用动力假肢，并在之前的访问期间练习行走。相同的方案是在不同的日子用被动膝关节和动力膝关节假体完成的。我们使用重复测量、双向方差分析 (alpha = 0.05) 来测试反馈和设备因素的显着影响。我们的主要结果指标是站立时间不对称性、峰值前后地面反作用力和峰值前推进力不对称性。结果通过视觉反馈增加截肢站立时间显着改善了使用两个假肢行走的个体的站立时间对称性（p = 0.012）和峰值推进对称性（p = 0.036）。与无反馈条件相比，使用动力膝关节假体时，最高反馈目标可使站立时间对称性提高 36%，假肢侧峰值推进力提高 22%，峰值推进对称性提高 47%。反馈变化与被动假肢没有差异，并且装置/假肢类型的主效应没有统计学差异。然而，受试者与设备之间的相互作用是显着的，表明个体对每种设备的反应不一致（例如，对于不同受试者，假肢侧推进力仍然与动力假肢相比或更大）。总体而言，动力假肢在不同条件下的假肢侧峰值推力平均提高了 31%，动力假肢的峰值推进不对称性提高了 48%。结论 通过视觉反馈增加假肢侧站立时间有利于改善个体的时间和推进对称性。动力假肢通常能够提供更大的推进力，但个体对每种设备的适应行为各不相同，需要进一步研究。