Bimodal Prosthetic Ankle-Foot System for Improved Balance and Mobility

描述（由申请人提供）： 下肢假肢使用者的站立平衡和平衡信心下降。这些平衡信心的下降与社交活动和生活质量的下降有关。目前的踝-足假体已经被设计成主要关注行走功能，尽管最近的研究表明假体中需要两种不同的功能模式来有效地模拟行走和站立任务。未来的假体将通过提供用于行走的弯曲有效摇杆形状和用于站立任务的平坦有效摇杆形状来更接近地模拟生物功能。申请人已经开发了能够提供这两种不同模式的原型，即双模态踝-足系统。本项目的主要目的是确定站立模式，它提供了一个平坦的有效的摇杆形状，可以改善与下肢截肢的退伍军人相比，弯曲（步行）模式的站立平衡。该项目将涉及24名单侧经胫骨截肢的退伍军人。在受试者提供参与该项目的知情同意书后，将收集受试者特定数据，并进行测试以记录轻微触摸和 完整肢体和残肢的振动感。受试者将接受培训，以使用其当前假体进行项目的平衡测试。训练结束后，受试者将带着他们当前的假肢走过走廊，并测量他们自己选择的正常速度。然后，受试者将使用当前的假肢进行功能活动度的L测试。在使用当前假肢完成平衡训练和活动测试后，受试者的残肢接受腔将从其当前假肢中取出，并连接到双踝足系统。受试者将有时间适应双踝足系统（设置为步行模式）。双模踝足系统将切换到站立模式，受试者将通过向各个方向倾斜来探索其支撑功能基础。双峰踝足系统的调节水平将模拟VA假肢机构的初始装配。接下来，受试者将在步行和站立模式下（以随机顺序）用脚踝进行以下平衡测试： - 安静站立，睁眼和闭眼，（2）动态姿势稳定性-稳定性极限，包括前足和脚跟倾斜，和（3）功能姿势稳定性-改良的运动控制测试，包括站立表面的平移扰动。我们假设，与弯曲形状相比，使用扁平有效摇杆形状时，受试者的静态、动态和功能姿势稳定性将得到改善。将在Minneapolis VA Health Care System使用NeuroCom Smart Equitest临床研究系统进行平衡测试。最后，将评估双模态踝足系统在弯曲（行走）模式下的行走活动性，包括收集行走速度和功能活动性L-检验的性能，以与当前假体进行比较。本研究的结果将为双踝足系统的进一步发展提供信息。它也将为未来的踝足假肢和矫形器提供这种设计方法的见解。例如，如果本研究的假设得到支持，未来的动力踝足假肢和矫形器可以在其设计中实施类似的策略，以改善其使用者的站立平衡。

DESCRIPTION (provided by applicant): Lower-limb prosthesis users have reduced standing balance and balance confidence. These reductions in balance confidence have been associated with reductions in social activities and quality of life. Current ankle- foot prostheses have been designed with a focus primarily on walking function, although recent studies suggest that two distinct functional modes are needed in the prosthesis to effectively mimic walking and standing tasks. Future prostheses would more closely mimic biologic function by providing a curved effective rocker shape for walking and a flat effective rocker shape for standing tasks. A prototype has been developed by the applicant that is capable of providing these two distinct modes, namely the bimodal ankle-foot system. The primary objective of this project is to determine if the standing mode, which provides a flat effective rocker shape, can improve the standing balance of veterans with lower-limb amputations compared with the curved (walking) mode. The project will involve 24 veterans with unilateral transtibial amputations. After subjects provide informed consent to participate in the project, subject-specific data will be collected and testing will occur to document light touch and vibratory sensation on the intact and residual limbs. Subjects will train to perform the balance tests of the project using their current prosthesis. After training, the subjects will walk througha hallway with their current prosthesis and their self-selected normal speed will be measured. The subjects will then perform an L-Test of functional mobility with their current prosthesis. After balance training and mobility testing with the current prosthesis is complete, the subject's residual limb socket will be removed from their current prosthesis and will be connected to the bimodal ankle-foot system. Subjects will be given time to accommodate to the bimodal ankle-foot system (set into walking mode). The bimodal ankle-foot system will be switched into standing mode and subjects will explore their functional base of support by leaning in various directions. The level of accommodation to the bimodal ankle-foot system will mimic that seen in an initial fitting at a VA prosthetics facility. Next, the subjects will perform the following balace tests with the ankle in walking and standing modes (in random order): (1) Static postural stability - Quiet standing with eyes open and eyes closed, (2) Dynamic postural stability - Limits of stability involving leaning over the forefeet and heels, and (3) Functional postural stability - Modified motor control test involving translational perturbations of the standing surface. We hypothesize that subjects' static, dynamic, and functional postural stability will be improved when using the flat effective rocker shape compared with the curved shape. Balance testing will be performed using a NeuroCom Smart Equitest Clinical Research System at the Minneapolis VA Health Care System. Lastly, walking mobility with the bimodal ankle-foot system in curved (walking) mode will be assessed, including collection of walking speed and performance of the L-Test of functional mobility, for comparison with the current prosthesis. The results of this stud will inform the further development of the bimodal ankle-foot system. It will also provide insight into this design approach for future ankle-foot prostheses and orthoses. For example, if the hypotheses of this study are supported, future powered ankle-foot prostheses and orthoses could implement similar strategies in their designs to improve standing balance of their users.