EMG propagation in planar muscles for prosthesis control

描述（由申请人提供）：目前上肢截肢者使用肌电义肢一次只能操作一个自由度。这是非常不充分的，特别是对于需要控制多种功能的高度截肢，如肩关节脱臼（SD）。我们假设，残臂丛神经可以移植到胸大肌的不同区域，这些神经-肌肉移植物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相关。这将使玩家能够同时控制多个自由度，并获得更自然的感觉。该技术在改善肌电SD假体的控制方面具有很大的潜力。这项技术成功的关键将是能够记录来自每个神经肌肉移植物的独立表面肌电信号。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计算机模型，并用实验数据进行验证。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影响将以实验方法无法实现的方式进行研究。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完成。接下来，将使用有限元分析来确定解剖操作对改善表面肌电信号独立性的影响，包括去除脂肪，集中记录部位的肌肉组织以及用脂肪层隔离肌肉。最后，受试者特定模型将用于模拟神经肌肉移植技术并测试这种新方法的可行性。解剖操作，以提高表面肌电信号的独立性也将测试与主体特定的模型。

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.