Center for Bionic Medicine, Rehabilitation Institute of Chicago, Chicago, IL 60611, USA.
IEEE Trans Biomed Eng. 2011 Sep;58(9):2537-44. doi: 10.1109/TBME.2011.2159216. Epub 2011 Jun 9.
Myoelectric pattern recognition systems for prosthesis control are often studied in controlled laboratory settings, but obstacles remain to be addressed before they are clinically viable. One important obstacle is the difficulty of maintaining system usability with socket misalignment. Misalignment inevitably occurs during prosthesis donning and doffing, producing a shift in electrode contact locations. We investigated how the size of the electrode detection surface and the placement of electrode poles (electrode orientation) affected system robustness with electrode shift. Electrodes oriented parallel to muscle fibers outperformed electrodes oriented perpendicular to muscle fibers in both shift and no-shift conditions (p < 0.01). Another finding was the significant difference (p < 0.01) in performance for the direction of electrode shift. Shifts perpendicular to the muscle fibers reduced classification accuracy and real-time controllability much more than shifts parallel to the muscle fibers. Increasing the size of the electrode detection surface was found to help reduce classification accuracy sensitivity to electrode shifts in a direction perpendicular to the muscle fibers but did not improve the real-time controllability of the pattern recognition system. One clinically important result was that a combination of longitudinal and transverse electrodes yielded high controllability with and without electrode shift using only four physical electrode pole locations.
用于假体控制的肌电模式识别系统通常在受控的实验室环境中进行研究，但在临床应用之前，仍有一些障碍需要解决。一个重要的障碍是在插座不对准的情况下，很难保持系统的可用性。不对准不可避免地会在假体穿脱过程中发生，从而导致电极接触位置发生移位。我们研究了电极检测面的大小和电极极（电极方向）的放置如何影响电极移位时系统的鲁棒性。与垂直于肌肉纤维的电极相比，平行于肌肉纤维的电极在移位和不移位条件下都表现更好（p < 0.01）。另一个发现是电极移位方向的性能存在显著差异（p < 0.01）。垂直于肌肉纤维的移位比平行于肌肉纤维的移位更严重地降低了分类准确性和实时可控性。研究发现，增加电极检测面的大小有助于减少垂直于肌肉纤维的电极移位对分类准确性的敏感性，但不能提高模式识别系统的实时可控性。一个具有临床意义的重要结果是，使用仅四个物理电极极位置，纵向和横向电极的组合在有和没有电极移位的情况下都具有很高的可控性。
