研究导致长期使用踝足矫形器和功能性电刺激器的慢性脑卒中患者跌倒的潜在生物力学机制。
Investigating the underlying biomechanical mechanisms leading to falls in long-term ankle-foot orthosis and functional electrical stimulator users with chronic stroke.
机构信息
School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, AZ, USA.
School of Biological and Health System Engineering, Arizona State University, Tempe, AZ, USA.
出版信息
Gait Posture. 2022 Feb;92:144-152. doi: 10.1016/j.gaitpost.2021.11.025. Epub 2021 Nov 20.
BACKGROUND
Ankle-foot-orthoses (AFOs) and functional electrical stimulators (FES) are commonly prescribed to treat foot-drop in individuals with stroke. Despite well-established positive impacts of AFO and FES devices on balance and gait, AFO and FES-users still fall at a high rate.
OBJECTIVE
The objective of this study was to investigate 1) the underlying biomechanical mechanisms leading to a fall in long-term AFO and FES-users with chronic stroke and 2) the impacts of AFOs and FES devices on fall outcomes and compensatory stepping response of long-term users with chronic stroke.
METHODS
Fall outcomes as well as kinematics and kinetics of compensatory stepping response of 42 individuals with chronic stroke (14 AFO-users, 10 FES-users, 18 Non-users) were evaluated during trip-like treadmill perturbations. AFO and FES-users were evaluated with and without their device.
RESULTS
Chronic AFO and FES-users fell 2.50 and 2.77 times more than Non-users. The most robust differences between AFO/FES-users and Non-users were 1) Reduced capacity to stabilize the trunk through reduction in forward whole-body angular momentum and 2) diminished capability to prepare and generate a second step using the paretic leg. Provocatively, the removal of AFO and FES devices did not decease/increase falls or change kinematics.
SIGNIFICANCE
It is well-established that AFOs/FES devices have a positive impact on static balance and decrease community falls by increasing toe clearance thus preventing trips/stumbles. However, our results suggest that once a trip occurs, these devices do not adequately assist recovery of balance. Specifically, current AFO and FES devices do not assist with second step generation or trunk control. Future studies should explore new devices or training paradigms that target enhancing trunk control and paretic compensatory stepping to decrease falls in this population.
背景
踝足矫形器（AFO）和功能性电刺激器（FES）常用于治疗中风患者的足下垂。尽管 AFO 和 FES 设备对平衡和步态有明确的积极影响，但 AFO 和 FES 用户仍有很高的跌倒率。
目的
本研究旨在探讨 1）长期使用 AFO 和 FES 治疗慢性中风患者跌倒的潜在生物力学机制，2）AFO 和 FES 设备对长期慢性中风患者跌倒结局和代偿性跨步反应的影响。
方法
在类似跑步机的扰动下，评估 42 名慢性中风患者（14 名 AFO 用户、10 名 FES 用户、18 名非使用者）的跌倒结局以及代偿性跨步反应的运动学和动力学。AFO 和 FES 用户在佩戴和不佩戴设备的情况下进行评估。
结果
慢性 AFO 和 FES 用户跌倒的次数是非使用者的 2.50 倍和 2.77 倍。AFO/FES 用户与非使用者之间最显著的差异是 1）通过减少前向整体角动量来降低稳定躯干的能力，2）通过使用瘫痪腿准备和产生第二步的能力下降。挑衅性地是，去除 AFO 和 FES 设备并没有减少/增加跌倒或改变运动学。
意义
已经确立的是，AFO/FES 设备对静态平衡有积极影响，通过增加足趾离地间隙来减少社区跌倒，从而防止绊倒/绊倒。然而，我们的结果表明，一旦发生跌倒，这些设备不能充分帮助恢复平衡。具体来说，目前的 AFO 和 FES 设备不能辅助产生第二步或躯干控制。未来的研究应该探索新的设备或训练模式，以提高躯干控制和瘫痪侧代偿性跨步，从而减少该人群的跌倒。
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