正常成人脑电信号多尺度分析

Multi-scale characteristics of EEG signals of normal adults

目的：研究正常成人脑电信号的多尺度特征。方法：记录20例正常成人安静闭目状态下脑电图，对其进行连续子波变换，观察脑电信号在不同尺度（频带）的细节特征，各尺度间的相互联系，以及能量分布特征。结果：正常成人脑电图的多尺度特征为各尺度（频带）的子波系数的幅值普遍相对较低，尺度（频带）分布范围较广，在特定的尺度范围内可见较强的相对稳定的节律性活动，相邻尺度间关联密切，呈层级关联的“家族”式结构，分尺度功率在0．1Hz、1Hz、10Hz附近形成三个峰的分布。结论：子波分析作为一种新的数学方法，适合于脑电信号的分析，通过子波分析可以获得脑电信号在不同尺度（频带）上的细节特征。脑电信号多尺度特征产生的生理生化机制有待于进一步研究。

Objective：To study the transient multi-scale features and multi-scale power distribution of the digital EEG signals and extract multi-scale features and multi-scale powers of EEG signals across scales in normal adults and to explore a new tool for digital EEG analysis, which is helpful to clinical di agnosis and basis research of neurology. Methods： In the analyse of digital EEG signals of 20 normal adults in eye-closed waking state with multi-scale resolution by wavelet transform, the qualitative multiscale features, power distributions across frequency and coordination of scalp were extracted. Results： The multi-scale feature of normal adults was that the wavelet coefficient was relatively small,its frequency range was relatively wide. The activity rhythm was relatively strong and relatively stable in several special scales. The correlation between adjoining scales was intimate, and three power peaks were located in Scale 8-10, Scale 13-15 and Scale 20-21. Conclusion： Wavelet analysis, as a new mathematical method, is a powerful tool to extract the multi-scale dataited features of EEG signals, by which more qualitative information and qualitative parameters from EEG can be captured. The physiological and chem ical processes, which reveals these specific features in each scale need further study in detail.