Palermo E, Rossi S, Patanè F, Cappa P
Department of Mechanical and Aerospace Engineering, 'Sapienza' University of Rome, Via Eudossiana 18, I-00184 Roma, Italy. Movement Analysis and Robotics Laboratory (MARLab), Neurorehabilitation Division, IRCCS Children's Hospital 'Bambino Gesù', Via Torre di Palidoro, I-00050 Passoscuro (Fiumicino) Roma, Italy.
Physiol Meas. 2014 Mar;35(3):399-415. doi: 10.1088/0967-3334/35/3/399. Epub 2014 Feb 5.
Magnetic inertial measurement unit systems (MIMU) offer the potential to perform joint kinematics evaluation as an alternative to optoelectronic systems (OS). Several studies have reported the effect of indoor magnetic field disturbances on the MIMU's heading output, even though the overall effect on the evaluation of lower limb joint kinematics is not yet fully explored. The aim of the study is to assess the influence of indoor magnetic field distortion on gait analysis trials conducted with a commercial MIMU system. A healthy adult performed gait analysis sessions both indoors and outdoors. Data collected indoors were post-processed with and without a heading correction methodology performed with OS at the start of the gait trial. The performance of the MIMU system is characterized in terms of indices, based on the mean value of lower limb joint angles and the associated ROM, quantifying the system repeatability. We find that the effects of magnetic field distortion, such as the one we experienced in our lab, were limited to the transverse plane of each joint and to the frontal plane of the ankle. Sagittal plane values, instead, showed sufficient repeatability moving from outdoors to indoors. Our findings provide indications to clinicians on MIMU performance in the measurement of lower limb kinematics.
磁惯性测量单元系统（MIMU）为进行关节运动学评估提供了一种替代光电系统（OS）的潜在方法。多项研究报告了室内磁场干扰对MIMU航向输出的影响，尽管其对下肢关节运动学评估的总体影响尚未得到充分探究。本研究的目的是评估室内磁场畸变对使用商用MIMU系统进行的步态分析试验的影响。一名健康成年人在室内和室外进行了步态分析测试。在步态试验开始时，对在室内收集的数据分别采用和不采用OS进行航向校正方法进行后处理。基于下肢关节角度的平均值和相关的活动范围，通过指标对MIMU系统的性能进行表征，以量化系统的可重复性。我们发现，磁场畸变的影响，例如我们在实验室中所经历的，仅限于每个关节的横断面和踝关节的额状面。相反，矢状面的值从室外到室内显示出足够的可重复性。我们的研究结果为临床医生提供了关于MIMU在测量下肢运动学方面性能的参考。
