Drawback of ICA Procedure on EEG: Polarity Indeterminacy at Local Optimization
Drawback of ICA Procedure on EEG: Polarity Indeterminacy at Local Optimization
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EEG ICA 程序的缺点：局部优化时的极性不确定性
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
H. Lyytinen
中科院分区：
文献类型：
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作者：
F. Cong;I. Kalyakin;T. Ristaniemi;H. Lyytinen
独立分量分析（伊卡）已被广泛应用于脑电信号（EEG）处理中去伪影。第一步是从电极记录中提取独立分量激活，然后将所需分量投影回电极。在详细分析了伊卡过程中投影分量的组成后，发现伊卡在高维脑电信号空间中可能会提取出局部最优的源分量，因此在某些电极上的投影分量可能会出现人为的极性不确定性。通过数值模拟，该问题也显示了这种极性模糊性的存在。因此，我们的结论是，异常极性反转应予以纠正，而没有事先了解所需的目标激活或伪影，投影分量的极性可能是不可靠的伊卡程序。
Independent component analysis (ICA) has been extensively applied to reject artifacts in electroencephalography (EEG) signal processing. The first step is to extract the independent component activations from the electrode records, and then project the desired components back to the electrodes. After the composition of the projected component is analyzed in details under ICA procedure, this study shows that since ICA may extract some source components at the local optimization in high-dimensional EEG signal space, the artificial polarity indeterminacy may happen on the projected component at some electrodes. By numerical simulations, this issue also exhibits that this polarity ambiguity occurs. Hence, we conclude that the abnormal polarity reversal should be corrected, and that without prior knowledge on the desired target activation or the artifacts, the polarity of the projected component may be not reliable under ICA procedure.