Echegoyen Ignacio, López-Sanz David, Martínez Johann H, Maestú Fernando, Buldú Javier M
Laboratory of Biological Networks, Centre for Biomedical Technology, Universidad Politécnica de Madrid (UPM), 28223 Madrid, Spain.
Complex Systems Group, Rey Juan Carlos University, 28933 Madrid, Spain.
Entropy (Basel). 2020 Jan 18;22(1):116. doi: 10.3390/e22010116.
We present one of the first applications of Permutation Entropy (PE) and Statistical Complexity (SC) (measured as the product of PE and Jensen-Shanon Divergence) on Magnetoencephalography (MEG) recordings of 46 subjects suffering from Mild Cognitive Impairment (MCI), 17 individuals diagnosed with Alzheimer's Disease (AD) and 48 healthy controls. We studied the differences in PE and SC in broadband signals and their decomposition into frequency bands ( δ , θ , α and β ), considering two modalities: (i) raw time series obtained from the magnetometers and (ii) a reconstruction into cortical sources or regions of interest (ROIs). We conducted our analyses at three levels: (i) at the group level we compared SC in each frequency band and modality between groups; (ii) at the individual level we compared how the [PE, SC] plane differs in each modality; and (iii) at the local level we explored differences in scalp and cortical space. We recovered classical results that considered only broadband signals and found a nontrivial pattern of alterations in each frequency band, showing that SC does not necessarily decrease in AD or MCI.
我们展示了排列熵（PE）和统计复杂性（SC）（以PE与詹森 - 香农散度的乘积来衡量）在46名轻度认知障碍（MCI）患者、17名被诊断为阿尔茨海默病（AD）的个体以及48名健康对照者的脑磁图（MEG）记录上的首批应用之一。我们研究了宽带信号及其分解为不同频段（δ、θ、α和β）时PE和SC的差异，考虑了两种模式：（i）从磁力计获得的原始时间序列；（ii）重建为皮质源或感兴趣区域（ROI）。我们在三个层面进行了分析：（i）在组间层面，我们比较了各频段和模式下各组之间的SC；（ii）在个体层面，我们比较了每种模式下[PE, SC]平面的差异；（iii）在局部层面，我们探究了头皮和皮质空间的差异。我们重现了仅考虑宽带信号时的经典结果，并在每个频段发现了显著的变化模式，表明SC在AD或MCI中不一定会降低。
