Jasni Farahiyah, Hamzaid Nur Azah, Mohd Syah Nor Elleeiana, Chung Tze Y, Abu Osman Noor Azuan
Department of Biomedical Engineering, Faculty of Engineering, University of MalayaKuala Lumpur, Malaysia.
Department of Mechatronics Engineering, Kulliyyah of Engineering, International Islamic University MalaysiaSelangor, Malaysia.
Front Neurosci. 2017 Apr 25;11:230. doi: 10.3389/fnins.2017.00230. eCollection 2017.
The walking mechanism of a prosthetic leg user is a tightly coordinated movement of several joints and limb segments. The interaction among the voluntary and mechanical joints and segments requires particular biomechanical insight. This study aims to analyze the inter-relationship between amputees' voluntary and mechanical coupled leg joints variables using cyclograms. From this analysis, the critical gait parameters in each gait phase were determined and analyzed if they contribute to a better powered prosthetic knee control design. To develop the cyclogram model, 20 healthy able-bodied subjects and 25 prosthesis and orthosis users (10 transtibial amputees, 5 transfemoral amputees, and 10 different pathological profiles of orthosis users) walked at their comfortable speed in a 3D motion analysis lab setting. The gait parameters (i.e., angle, moment and power for the ankle, knee and hip joints) were coupled to form 36 cyclograms relationship. The model was validated by quantifying the gait disparities of all the pathological walking by analyzing each cyclograms pairs using feed-forward neural network with backpropagation. Subsequently, the cyclogram pairs that contributed to the highest gait disparity of each gait phase were manipulated by replacing it with normal values and re-analyzed. The manipulated cyclograms relationship that showed highest improvement in terms of gait disparity calculation suggested that they are the most dominant parameters in powered-knee control. In case of transfemoral amputee walking, it was identified using this approach that at each gait sub-phase, the knee variables most responsible for closest to normal walking were: knee power during loading response and mid-stance, knee moment and knee angle during terminal stance phase, knee angle and knee power during pre-swing, knee angle at initial swing, and knee power at terminal swing. No variable was dominant during mid-swing phase implying natural pendulum effect of the lower limb between the initial and terminal swing phases. The outcome of this cyclogram adoption approach proposed an insight into the method of determining the causal effect of manipulating a particular joint's mechanical properties toward the joint behavior in an amputee's gait by determining the curve closeness, C, of the modified cyclogram curve to the normal conventional curve, to enable quantitative judgment of the effect of changing a particular parameter in the prosthetic leg gait.
假肢使用者的行走机制是多个关节和肢体节段紧密协调的运动。自主关节和机械关节及节段之间的相互作用需要特定的生物力学见解。本研究旨在使用周期图分析截肢者自主和机械耦合的腿部关节变量之间的相互关系。通过该分析，确定每个步态阶段的关键步态参数，并分析它们是否有助于更好的动力假肢膝关节控制设计。为了建立周期图模型，20名健康的身体健全受试者和25名假肢和矫形器使用者（10名胫骨截肢者、5名股骨截肢者和10名不同病理特征的矫形器使用者）在3D运动分析实验室环境中以舒适的速度行走。步态参数（即踝关节、膝关节和髋关节的角度、力矩和功率）被耦合以形成36种周期图关系。通过使用具有反向传播的前馈神经网络分析每个周期图对，量化所有病理行走的步态差异来验证该模型。随后，通过用正常值替换导致每个步态阶段最大步态差异的周期图对并重新分析。在步态差异计算方面显示出最大改善的经操作的周期图关系表明它们是动力膝关节控制中最主要的参数。在股骨截肢者行走的情况下，使用这种方法确定，在每个步态子阶段，最接近正常行走的膝关节变量是：负重反应和支撑中期的膝关节功率、终末支撑期的膝关节力矩和膝关节角度、摆动前期的膝关节角度和膝关节功率、初始摆动时的膝关节角度以及终末摆动时的膝关节功率。在摆动中期没有变量占主导，这意味着下肢在初始和终末摆动阶段之间的自然摆动效应。这种周期图采用方法的结果提出了一种见解，即通过确定修改后的周期图曲线与正常传统曲线的曲线接近度C，来确定操纵特定关节的机械特性对截肢者步态中关节行为的因果效应的方法，从而能够对假肢步态中改变特定参数的效果进行定量判断。
