Characterization and clinical trial of a Variable Friction Shoe, a new paradigm of reduced-constraint locomotor therapy for people exhibiting foot drop due to stroke

项目摘要 100多万美国人中风后足部下垂，并经常制定补偿策略 以避免擦伤脚。目前脚下垂的治疗方法是通过应用非 对脚踝施加意志力，以防止足底屈曲。两种最常见的此类设备是 踝足矫形器(AFO)和功能性电刺激(FES)，两者都提供了很好的证据 矫形效果，帮助用户在佩戴设备时行走。然而，治疗效果有限，使用者 很少会有足够的进步来停止需要他们的设备。 因此，我们在这里提出了一种替代策略，即使在允许的情况下也可以解决绊倒的危险 完全控制脚踝的意志：一种廉价的可变摩擦(VF)鞋。它的外底是高摩擦的 步态的站立阶段和挥杆过程中的低摩擦力；此外，当发生擦伤时，它会产生“滴答声”。证据 这表明这种反馈可以提高治疗效果。我们的初步数据显示VF鞋 能立即提高步态速度(矫形效果)，并在长期使用后有效，即使当鞋子 去除(治疗效果)。 我们的中心假设是，允许脚踝的自愿运动，同时减轻绊倒的危险 步态阶段性听觉生物反馈将改善足下垂受试者的步态。具体来说，我们 假设VF鞋将比AFO显示出显著更大的治疗效果，但仍保持 AFO具有理想的矫形效果。我们把工作安排在两个目标上。 具体目标1：描述VF鞋在使用寿命内的磨擦力减少情况。至关重要的是 了解VF鞋的效果是对磨擦力减少程度的表征。 具体目标2：评估VF鞋对慢性中风和跌倒患者步态的影响 脚。在AB-BA临床试验的每个12周阶段，参与者将至少步行30-45分钟 每周至少有5天呆在家里。 我们希望这项工作将验证我们的VF鞋作为一种工具，以改善中风后的步态，并将推出 足下垂疗法的新范式：完全自愿控制脚踝，同时减轻绊倒。这一结果将为 为未来在VF鞋上进行关键设备试验以评估临床疗效奠定了基础。重要的是，VF鞋是 简单、低成本和易于使用，使广泛的家庭收养成为可能。

Project Summary More than one million Americans present with foot drop after stroke and often develop compensatory strategies to avoid scuffing the foot. Current treatment for foot drop addresses the hazard of tripping by applying non- volitional torques to the ankle to prevent the foot from plantarflexing. The two most common such devices are the Ankle Foot Orthosis (AFO) and Functional Electrical Stimulation (FES), which both provide well-documented orthotic effects to help users walk while the device is worn. However, therapeutic effects are limited, and users rarely improve enough to cease needing their device. Accordingly, here we propose an alternative strategy that addresses the hazard of tripping even while allowing full volitional control of the ankle: an inexpensive Variable Friction (VF) shoe. Its outsole is high-friction during the stance phase of gait and low friction during swing; further, it produces a “click” when a scuff occurs. Evidence suggests that such feedback can enhance therapeutic outcomes. Our preliminary data suggests that the VF shoe is effective at increasing gait speed immediately (orthotic effect) and after long term use, even when the shoe is removed (therapeutic effect). Our central hypothesis is that allowing volitional motion of the ankle while mitigating the hazard of tripping coupled with gait-phased auditory biofeedback will result in improved gait for subjects with drop foot. Specifically, we hypothesize that the VF shoe will show significantly greater therapeutic effects than an AFO, yet maintain the desirable orthotic effect of the AFO. We arrange our work in two Aims. Specific Aim 1: Characterize the scuff-force reduction of the VF shoe over the lifetime of use. Critical to understanding the effects of the VF shoe is a characterization of the level of scuff-force reduction. Specific Aim 2: Evaluate the effects of the VF shoe on gait in individuals with chronic stroke and drop foot. During each 12-week phase of an AB-BA clinical trial, participants will walk for at least 30-45 minutes per day for at least 5 days per week at home. We expect that this work will validate our VF shoe as a tool for improving gait after stroke and will introduce a new paradigm for drop foot therapy: fully volitional ankle control while mitigating tripping. The results will lay the foundation for a future pivotal device trial on the VF shoe to assess clinical efficacy. Importantly, the VF shoe is simple, low-cost and easy-to-use, making wide-ranging home-based adoption feasible.