Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
J Electromyogr Kinesiol. 1994;4(1):15-26. doi: 10.1016/1050-6411(94)90023-X.
The purpose of this paper is to address four aspects of surface electromyography associated with crosstalk between adjacent recording sites. The first issue that is addressed in the potential crosstalk between electrodes located on muscles with different functions: antagonist pairs, or muscles with one common and one different function (i.e. soleus/peroneus longus or soleus/ gastrocnemius). Practical functional tests are utilized to demonstrate the crosstalk between muscle pairs to be negligible. The second goal is to estimate the depth of pick-up and the crosstalk between myoelectric signals from agonist muscles using a theoretical model. The depth of pick-up was estimated to be 1.8 cm (including a 2 mm layer of skin and fat) using electrodes of 49 mm(2) with bipolar spacing of 2.0 cm. A cross-correlation technique is demonstrated which predicts the common signal (crosstalk) between surface electrodes with electrode-pair spacing of 1 cm around a hypothetical muscle. The predicted crosstalk using cross-correlation measures was 49% at 1 cm electrode-pair spacing dropping to 13% at 2 cm spacing and 4% at 3 cm. The third part compares these predictions with crosstalk measures from experimental recordings taken from electrode pairs spaced 2.5 cm apart around the quadriceps. At 2.5 cm spacing there was 22-24% common signal dropping to between 4-7% at 5 cm and to between 1 and 2% at 7.5 cm. The fourth and last component of this report assesses three methods to decrease the range of pick-up and thereby potential crosstalk: electrodes of smaller surface area, reduced bipolar spacing and mathematical differentiation. All three techniques reduce the common signal by varying amounts; all three techniques combined reduce the predicted crosstalk for the 1.0 cm electrode-pair spacing from 49-10.5%.
本文旨在探讨与相邻记录部位之间串扰相关的表面肌电图的四个方面。首先讨论了位于具有不同功能的肌肉上的电极之间（例如拮抗肌对或具有一个共同功能和一个不同功能的肌肉，例如比目鱼肌/腓肠肌或比目鱼肌/胫骨前肌）的潜在电串扰问题。利用实际的功能测试证明，肌肉对之间的串扰可忽略不计。第二个目标是使用理论模型估算来自协同肌的拾电深度和肌电信号之间的串扰。使用间距为 2.0 cm 的 49mm²的双极电极，估计拾电深度为 1.8 cm（包括 2mm 厚的皮肤和脂肪层）。展示了一种互相关技术，该技术可预测在假想肌肉周围电极对间距为 1cm 的表面电极之间的公共信号（串扰）。使用互相关测量值预测的串扰在 1cm 电极对间距处为 49%，在 2cm 间距处降至 13%，在 3cm 间距处降至 4%。第三部分将这些预测与从相距 2.5cm 的电极对周围记录的实验记录中的串扰测量值进行了比较。在 2.5cm 间距处，有 22-24%的公共信号下降到 5cm 处的 4-7%，以及 7.5cm 处的 1-2%。本报告的第四部分和最后一部分评估了三种减小拾电范围从而减小潜在串扰的方法：表面积较小的电极，减小双极间距和数学微分。所有三种技术都以不同程度减少了公共信号；三种技术的组合将 1.0cm 电极对间距的预测串扰从 49-10.5%降低。
