Bashar M R, Li Y, Wen P
Department of Mathematics and Computing, Centre for Systems Biology, University of Southern Queensland, Toowoomba, QLD, 4350, Australia.
Australas Phys Eng Sci Med. 2010 Jun;33(2):145-52. doi: 10.1007/s13246-010-0015-7. Epub 2010 May 26.
The accuracy of an electroencephalography (EEG) forward problem partially depends on the head tissue conductivities. These conductivities are anisotropic and inhomogeneous in nature. This paper investigates the effects of conductivity uncertainty and analyses its sensitivity on an EEG forward problem for a spherical and a realistic head models. We estimate the uncertain conductivities using an efficient constraint based on an optimization method and perturb it by means of the volume and directional constraints. Assigning the uncertain conductivities, we construct spherical and realistic head models by means of a stochastic finite element method for fixed dipolar sources. We also compute EEG based on the constructed head models. We use a probabilistic sensitivity analysis method to determine the sensitivity indexes. These indexes characterize the conductivities with the most or the least effects on the computed outputs. These results demonstrate that conductivity uncertainty has significant effects on EEG. These results also show that the uncertain conductivities of the scalp, the radial direction of the skull and transversal direction in the white matter are more sensible.
脑电图（EEG）正问题的准确性部分取决于头部组织的电导率。这些电导率本质上是各向异性且不均匀的。本文研究了电导率不确定性的影响，并分析了其对球形和真实头部模型的EEG正问题的敏感性。我们使用基于优化方法的有效约束来估计不确定的电导率，并通过体积和方向约束对其进行扰动。分配不确定的电导率后，我们通过随机有限元方法为固定偶极源构建球形和真实头部模型。我们还基于构建的头部模型计算EEG。我们使用概率敏感性分析方法来确定敏感性指标。这些指标表征了对计算输出影响最大或最小的电导率。这些结果表明，电导率不确定性对EEG有显著影响。这些结果还表明，头皮、颅骨径向和白质横向的不确定电导率更敏感。
