Fine detection of grasp force and posture by amputees via surface electromyography
Fine detection of grasp force and posture by amputees via surface electromyography
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DOI：
10.1016/j.jphysparis.2009.08.008
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发表时间：
2009-05-01
影响因子：
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通讯作者：
Sandini, Giulio
中科院分区：
文献类型：
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作者：
Castellini, Claudio;Gruppioni, Emanuele;Sandini, Giulio
目前主动假手的前馈控制效果较差。即使是灵巧的、多指的商业假肢也是通过表面肌电图（EMG）来控制的，其方式是强制执行一些固定的抓握姿势，或者对力的非常基本的估计。控制不是自然的，这意味着截肢者必须学会联想，例如，手腕弯曲和手闭合。然而，最近的文献表明，更多的信息可以收集从平原，旧的表面肌电图。为了检查这个问题，我们进行了一项实验，其中三名截肢者使用五个市售的EMG电极训练支持向量机（SVM），同时要求他们用幻肢执行各种抓握姿势和力量。与最近关于皮质可塑性的神经学研究一致，我们表明，几十年前接受手术的截肢者仍然可以为每个姿势和力量产生独特而稳定的信号。SVM对姿势进行分类的精度高达95%，并在25 Hz下逐个样本地近似力，误差仅为信号范围的7%。这些值与健康受试者在前馈控制灵巧机械手时先前获得的结果一致。然后，我们得出结论，我们的主题可以精细前馈控制灵巧的假肢在力和位置，使用标准的EMG在一个自然的方式，即使用幻肢。(C)2009爱思唯尔有限公司保留所有权利。
The state-of-the-art feed-forward control of active hand prostheses is rather poor. Even dexterous, multi-fingered commercial prostheses are controlled via surface electromyography (EMG) in a way that enforces a few fixed grasping postures, or a very basic estimate of force. Control is not natural, meaning that the amputee must learn to associate, e.g., wrist flexion and hand closing. Nevertheless, recent literature indicates that much more information can be gathered from plain, old surface EMG. To check this issue, we have performed an experiment in which three amputees train a Support Vector Machine (SVM) using five commercially available EMG electrodes while asked to perform various grasping postures and forces with their phantom limbs. In agreement with recent neurological studies on cortical plasticity, we show that amputees operated decades ago can still produce distinct and stable signals for each posture and force. The SVM classifies the posture up to a precision of 95% and approximates the force with an error of as little as 7% of the signal range, sample-by-sample at 25 Hz. These values are in line with results previously obtained by healthy subjects while feed-forward controlling a dexterous mechanical hand. We then conclude that our subjects could finely feed-forward control a dexterous prosthesis in both force and position, using standard EMG in a natural way, that is, using the phantom limb. (C) 2009 Elsevier Ltd. All rights reserved.