Baston Chiara, Mancini Martina, Schoneburg Bernadette, Horak Fay, Rocchi Laura
Department of Electrical, Electronic and Information Engineering "Guglielmo Marconi", University of Bologna, Bologna, Italy.
Department of Neurology, School of Medicine, Oregon Health & Science University, 3181 Sam Jackson Park Road, Portland, OR 97239-3098, USA(1).
Gait Posture. 2014;40(1):70-5. doi: 10.1016/j.gaitpost.2014.02.012. Epub 2014 Mar 2.
The present study introduces a novel instrumented method to characterize postural movement strategies to maintain balance during stance (ankle and hip strategy), by means of inertial sensors, positioned on the legs and on the trunk. We evaluated postural strategies in subjects with 2 types of Parkinsonism: idiopathic Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP), and in age-matched control subjects standing under perturbed conditions implemented by the Sensory Organization Test (SOT). Coordination between the upper and lower segments of the body during postural sway was measured using a covariance index over time, by a sliding-window algorithm. Afterwards, a postural strategy index was computed. We also measured the amount of postural sway, as adjunctive information to characterize balance, by the root mean square of the horizontal trunk acceleration signal (RMS).
showed that control subjects were able to change their postural strategy, whilst PSP and PD subjects persisted in use of an ankle strategy in all conditions. PD subjects had RMS values similar to control subjects even without changing postural strategy appropriately, whereas PSP subjects showed much larger RMS values than controls, resulting in several falls during the most challenging SOT conditions (5 and 6). Results are in accordance with the corresponding clinical literature describing postural behavior in the same kind of subjects. The proposed strategy index, based on the use of inertial sensors on the upper and lower body segments, is a promising and unobtrusive tool to characterize postural strategies performed to attain balance.
本研究引入了一种新颖的仪器化方法，通过置于腿部和躯干上的惯性传感器来表征在站立时维持平衡的姿势运动策略（踝关节和髋关节策略）。我们评估了患有两种帕金森症类型的受试者的姿势策略：特发性帕金森病（PD）和进行性核上性麻痹（PSP），以及年龄匹配的对照受试者在由感觉组织测试（SOT）实施的扰动条件下站立时的姿势策略。使用滑动窗口算法，通过随时间变化的协方差指数来测量姿势摆动期间身体上下节段之间的协调性。之后，计算姿势策略指数。我们还通过水平躯干加速度信号的均方根（RMS）测量姿势摆动量，作为表征平衡的辅助信息。
表明对照受试者能够改变他们的姿势策略，而PSP和PD受试者在所有条件下都持续使用踝关节策略。即使没有适当地改变姿势策略，PD受试者的RMS值也与对照受试者相似，而PSP受试者的RMS值比对照受试者大得多，导致在最具挑战性的SOT条件（5和6）下多次跌倒。结果与描述同类受试者姿势行为的相应临床文献一致。所提出的基于在上半身和下半身节段使用惯性传感器的策略指数，是一种有前景且不引人注目的工具，用于表征为达到平衡而执行的姿势策略。
