EMG propagation in planar muscles for prosthesis control

描述（申请人提供）：目前上肢截肢者只能使用肌电假肢一次操作一个自由度。这是非常不够的，特别是对于高度截肢，如肩关节离断（SD），其中需要控制多个功能。我们假设，在SD截肢者的残余臂丛神经可以移植到胸大肌（pmajor）肌肉的单独区域，这些神经肌肉移植物可以提供额外的肌电控制信号，生理相关的功能，他们将在假体控制。这将允许以更自然的感觉同时控制多个自由度。该技术具有很大的潜力，以提高肌电SD假体的控制。这项技术成功的关键是能够记录来自每个神经肌肉移植物的独立表面EMG信号。为了研究肌电信号在胸部中的独立性，将开发一系列肌电信号在胸部中传播的有限元（FE）计算机模型，并利用实验数据进行验证。使用有限元分析，它是可能的模拟表面肌电信号在一系列不同的条件下。肌肉解剖结构、生物组织特性和记录电极配置等效应将以使用实验方法无法实现的方式进行研究。首先，FE分析将用于调查表面EMG信号独立性与活动肌肉、邻近肌肉和记录部位附近的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解剖操作对改善表面EMG信号独立性的影响，包括去除脂肪、在记录部位集中肌肉组织以及用脂肪层隔离肌肉。最后，将使用特定对象的模型来模拟神经肌肉移植技术，并测试这种新方法的可行性。还将使用受试者特定模型测试增强表面EMG信号独立性的解剖操作。

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.