EMG propagation in planar muscles for prosthesis control

描述(申请人提供)：目前，使用肌电假体的上肢截肢者一次只能操作一个自由度。这是非常不够的，特别是对于肩关节脱位(SD)等需要控制多种功能的高位截肢。我们推测，SD截肢者残存的臂丛神经可以移植到胸大肌的不同区域，这些神经-肌肉移植可以提供额外的肌电控制信号，这些信号在生理上与它们在假体中控制的功能有关。这将允许以更自然的感觉同时控制多个自由度。这项技术在改善肌电SD假体的控制方面具有巨大的潜力。这项技术成功的关键将是记录每个神经肌肉移植物的独立表面肌电信号的能力。为了研究肌电信号在胸部的独立性，建立了一系列肌电信号在胸部传播的有限元(FE)计算机模型，并用实验数据进行了验证。利用有限元分析，可以模拟一系列不同条件下的表面肌电信号。肌肉解剖、生物组织特性和记录电极配置等效应将以一种使用实验方法不可能的方式进行研究。首先，将使用有限元分析来研究表面肌电信号独立性与活动肌肉、邻近肌肉和记录部位附近其他组织的几何形状之间的关系。这将通过一系列广义平面有限元模型来实现。接下来，将使用有限元分析来确定改善表面肌电信号独立性的解剖手法的效果，包括去除脂肪、在记录部位集中肌肉组织以及用一层脂肪隔离肌肉。最后，将使用特定于对象的模型来模拟神经-肌肉移植技术，并测试该新方法的可行性。增强表面肌电信号独立性的解剖操作也将用特定于对象的模型进行测试。

DESCRIPTION (provided by applicant): Currently upper-limb amputees can only operate a single degree-of-freedom at a time with myoelectric prostheses. This is very inadequate, especially for high-levels of amputation such as shoulder disarticulation(SD) where multiple functions need to be controlled. We postulate that the residual brachial plexus nerves in a SD amputee can be grafted onto separate regions of the pectoralis major (pmajor) muscle and that these nerve-muscle grafts could provide additional myoelectric control signals that are physiologically related to the functions they would be controlling in the prosthesis. This would allow simultaneous control of multiple degrees-of-freedom with a more natural feel. The technique has great potential for improving the control of myoelectric SD prostheses. The key to success with this technique will be the ability to record independent surface EMG signals from each of the nerve-muscle grafts. In order to study EMG signal independence in the chest, a series of finite element (FE) computer models of EMG signal propagation in the chest will be developed and validated with experimental data. Using FE analysis, it is possible to simulate surface EMG signals under a range of different conditions. Effects such as muscle anatomy, biological tissue properties and recording electrode configuration will be investigated in a manner not possible using experimental methods. First, FE analysis will be used to investigate the relationship between surface EMG signal independence and the geometry of the active muscle, neighboring muscles and other tissues near the recording site. This will be accomplished with a series of generalized planar FE models. Next, finite element analysis will be used to determine the effect of anatomical manipulations for improving surface EMG signal independence including removal of fat, concentrating muscle tissue at recording sites and insulating muscles with a layer of fat. Finally, the subject-specific models will be used to simulate the nerve-muscle graft technique and test the feasibility of this novel approach. Anatomical manipulations to enhance surface EMG signal independence will also be tested with the subject-specific models.