Knowledge of the upper extremity (UE) effort exerted under real-world conditions is important for understanding how persons with motor or sensory disorders perform the postural shifts necessary to complete many activities of daily living while standing. To this end, a feedback controller, named the “Posture Follower Controller”, was developed to aid in task-dependent posture shifting by individuals with spinal cord injury standing with functional neuromuscular stimulation. In this experimental feasibility study, the controller modulated activation to the paralyzed lower extremity muscles as a function of the position of overall center of pressure (CoP), which was prescribed to move in a straight line in forward and diagonal directions. Posture-dependent control of stimulation enabled leaning movements that translated the CoP up to 48 mm away from the nominal position during quiet standing. The mean 95% prediction ellipse area, a measure of the CoP dispersion in the forward, forward-right, and forward-left directions, was , , and , respectively. The average width of the prediction ellipses across the three directions was 15.1 mm, indicating that the CoP deviated from the prescribed path as task-dependent postures were assumed. The average maximal UE effort required to adjust posture across all leaning directions was 24.1% body weight, which is only slightly more than twice of what is required to maintain balance in an erect standing posture. These preliminary findings suggest that stimulation can be modulated to effectively assume user-specified, task-dependent leaning postures characterized by the CoP shifts that deviate away from the nominal position and which require moderate UE effort to execute.

中文翻译：

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植入式站立神经假体中姿势依赖性刺激自动控制的实验实施。

了解在现实世界条件下施加的上肢 (UE) 努力对于了解运动或感觉障碍患者如何在站立时完成许多日常生活活动所必需的姿势转变非常重要。为此，开发了一种名为“姿势跟随控制器”的反馈控制器，以帮助脊髓损伤患者在功能性神经肌肉刺激下站立时进行任务相关的姿势转换。在这项实验可行性研究中，控制器根据整体压力中心 (CoP) 的位置调节瘫痪下肢肌肉的激活，该压力中心被规定在向前和对角线方向上沿直线移动。依赖于姿势的刺激控制使倾斜运动能够在安静站立期间将 CoP 从标称位置平移 48 毫米。平均 95% 的预测椭圆面积是 CoP 在前向、前右和前左方向上离散度的量度，为, ,和，分别。三个方向上预测椭圆的平均宽度为 15.1 mm，表明 CoP 偏离了规定的路径，因为假设了任务相关的姿势。在所有倾斜方向上调整姿势所需的平均最大 UE 努力为 24.1% 体重，这仅是保持直立姿势平衡所需的两倍多。这些初步研究结果表明，可以调节刺激以有效地采取用户指定的、任务相关的倾斜姿势，其特征是 CoP 偏移偏离标称位置并且需要适度的 UE 努力来执行。