Shorter Amanda L, Finucane Suzanne, Rouse Elliott J
IEEE Int Conf Rehabil Robot. 2019 Jun;2019:246-251. doi: 10.1109/ICORR.2019.8779436.
Dynamic joint mechanics, collectively known as mechanical impedance, are often altered following upper motoneuron disease, which can hinder mobility for these individuals. Typically, assessments of altered limb mechanics are obtained while the patient is at rest, which differs from the dynamic conditions of mobility. The purpose of this study was to quantify ankle impedance during walking in individuals post-stroke, determine differences from the healthy population, and assess the relationship between impedance impairment and clinical outcome measures. Preliminary data were collected in four individuals post-stroke. Displacement perturbations were applied to the ankle during stance phase, and least-squares system identification was performed to estimate ankle impedance. In comparison to the healthy population, the paretic ankle showed reduced variation of stiffness during mid-stance of walking, and damping estimates during early and mid-stance were increased. Clinical measures obtained during dynamic tasks showed strong correlation with changes to the stiffness component of impedance, while clinical measures obtained passively were not correlated to stiffness. Impairment in ankle damping was not correlated with any of the measures tested. This work provides novel, preliminary insight into paretic ankle impedance during walking, differences from healthy data, and elucidates how current clinical metrics correspond to the true values of ankle stiffness and damping during gait.
动态关节力学，统称为机械阻抗，在上运动神经元疾病后常常会发生改变，这可能会阻碍这些个体的活动能力。通常，对肢体力学改变的评估是在患者休息时进行的，这与活动时的动态情况不同。本研究的目的是量化中风后个体行走过程中的踝关节阻抗，确定与健康人群的差异，并评估阻抗损伤与临床结局指标之间的关系。在四名中风后个体中收集了初步数据。在站立期对踝关节施加位移扰动，并进行最小二乘系统识别以估计踝关节阻抗。与健康人群相比，患侧踝关节在行走中期站立时刚度变化减小，在早期和中期站立时阻尼估计值增加。在动态任务中获得的临床测量结果与阻抗刚度成分的变化密切相关，而被动获得的临床测量结果与刚度无关。踝关节阻尼损伤与所测试的任何指标均无相关性。这项工作为行走过程中患侧踝关节阻抗、与健康数据的差异提供了新颖的初步见解，并阐明了当前临床指标如何与步态期间踝关节刚度和阻尼的真实值相对应。
