Väisänen Outi, Malmivuo Jaakko
Department of Biomedical Engineering, Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere, Finland.
J Physiol Paris. 2009 Nov;103(6):306-14. doi: 10.1016/j.jphysparis.2009.07.003. Epub 2009 Jul 18.
We have developed a multielectrode lead technique to improve the signal-to-noise ratio (SNR) of scalp-recorded electroencephalography (EEG) signals generated deep in the brain. The basis of the method lies in optimization of the measurement sensitivity distribution of the multielectrode lead. We claim that two factors improve the SNR in a multielectrode lead: (1) the sensitivity distribution of a multielectrode lead is more specific in measuring signals generated deep in the brain and (2) spatial averaging of noise occurs when several electrodes are applied in the synthesis of a multielectrode lead. We showed theoretically that within a three-layer spherical head model the sensitivity distributions of multielectrode leads are more specific for deep sources than those of traditional bipolar leads. We also estimated with simulations and with preliminary measurements the total improvement in SNR achieved by both the more specific lead field and spatial averaging. Results obtained with simulations and with experimental measurements show an apparent improvement in SNR obtained with multielectrode leads. This encourages for future development of the method.
我们开发了一种多电极导联技术，以提高在头皮记录的源自大脑深部的脑电图（EEG）信号的信噪比（SNR）。该方法的基础在于优化多电极导联的测量灵敏度分布。我们认为有两个因素可提高多电极导联的信噪比：（1）多电极导联的灵敏度分布在测量源自大脑深部的信号时更具特异性，（2）在合成多电极导联时应用多个电极时会发生噪声的空间平均。我们从理论上表明，在三层球形头部模型中，多电极导联的灵敏度分布对于深部源比传统双极导联更具特异性。我们还通过模拟和初步测量估计了更具特异性的导联场和空间平均所实现的信噪比的总体改善。模拟和实验测量获得的结果表明，多电极导联的信噪比有明显改善。这为该方法的未来发展提供了动力。
