Volume conduction in an anatomically based surface EMG model
Volume conduction in an anatomically based surface EMG model
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DOI：
10.1109/tbme.2004.836494
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发表时间：
2004-12-01
影响因子：
4.6
通讯作者：
Kuiken, TA
中科院分区：
文献类型：
--
作者：
Lowery, MM;Stoykov, NS;Kuiken, TA
提出了一种模拟真实人体上臂表面肌电信号的有限元模型。该模型被用来探索肢体几何形状对表面检测的肌肉纤维动作电位的影响。该模型基于受试者上臂的磁共振图像，包括阻性和电容性材料属性。为了验证模型的几何形状，在皮肤表面施加亚阈值正弦电流源的过程中，比较了不同电极位置的实验电位和模拟电位。在所检测的材料性质中，最接近实验数据的归一化表面电势的平均均方根(RMS)误差为18%或27%，具体取决于施加源的位置。然后比较了基于相同肢体几何形状的理想圆柱体模型和现实体导体模型所模拟的表面检测动作电位。模拟肢体几何形状的变化对动作电位的形状有相当大的影响。然而，在两种模型中，动作电位幅度的衰减率随着距离纤维的增加而相似。电容材料特性的包含导致了表面动作电位的临时低通滤波。这种效应在远离活性纤维的部位检测到的动作电位的末端效应成分中最为明显。结论是，当感兴趣的特定动作电位形状时，对肢体几何形状、不对称性、组织电容和纤维曲率的准确建模是重要的。然而，如果目标是研究更多的表面肌电信号的定性特征，那么具有适当组织厚度的理想化的体导体模型提供了一个接近的近似。
A finite-element model to simulate surface electromyography (EMG) in a realistic human upper arm is pre-sented. The model is used to explore the effect of limb geometry on surface-detected muscle fiber action potentials. The model was based on magnetic resonance images of the subject's upper arm and includes both resistive and capacitive material properties. To validate the model geometry, experimental and simulated potentials were compared at different electrode sites during the application of a subthreshold sinusoidal current source to the skin surface. Of the material properties examined, the closest approximation to,the experimental data yielded a mean root-mean-square (rms) error of the normalized surface potential of 18% or 27%, depending on the site of the applied source. Surface-detected action potentials simulated using the realistic volume conductor model and an idealized cylindrical model based on the same limb geometry were then compared. Variation in the simulated limb geometry had a considerable effect on action potential shape. However, the rate of decay of the action potential amplitude with increasing distance from the fiber was similar in both models. Inclusion of capacitive material properties resulted in temporal low-pass filtering of the surface action potentials. This effect was most pronounced in the end-effect components of action potentials detected at locations far from the active fiber. It is concluded that accurate modeling of the limb geometry, asymmetry, tissue capacitance and fiber curvature is important when the specific action potential shapes are of interest. However, if the objective is to examine more, qualitative features of the surface EMG signal, then an idealized volume conductor model with appropriate tissue thicknesses provides a close approximation.