Vecchio Fabrizio, Miraglia Francesca, Marra Camillo, Quaranta Davide, Vita Maria Gabriella, Bramanti Placido, Rossini Paolo Maria
Brain Connectivity Laboratory, IRCCS San Raffaele Pisana, Rome, Italy.
Institute of Neurology, Catholic University, Rome, Italy Center for Neuropsychological Research, Catholic University, Rome, Italy.
J Alzheimers Dis. 2014;41(1):113-27. doi: 10.3233/JAD-132087.
The aim of this study was to investigate the neuronal network characteristics in physiological and pathological brain aging. A database of 378 participants divided in three groups was analyzed: Alzheimer's disease (AD), mild cognitive impairment (MCI), and normal elderly (Nold) subjects. Through EEG recordings, cortical sources were evaluated by sLORETA software, while graph theory parameters (Characteristic Path Length λ, Clustering coefficient γ, and small-world network σ) were computed to the undirected and weighted networks, obtained by the lagged linear coherence evaluated by eLORETA software. EEG cortical sources from spectral analysis showed significant differences in delta, theta, and alpha 1 bands. Furthermore, the analysis of eLORETA cortical connectivity suggested that for the normalized Characteristic Path Length (λ) the pattern differences between normal cognition and dementia were observed in the theta band (MCI subjects are find similar to healthy subjects), while for the normalized Clustering coefficient (γ) a significant increment was found for AD group in delta, theta, and alpha 1 bands; finally, the small world (σ) parameter presented a significant interaction between AD and MCI groups showing a theta increase in MCI. The fact that AD patients respect the MCI subjects were significantly impaired in theta but not in alpha bands connectivity are in line with the hypothesis of an intermediate status of MCI between normal condition and overt dementia.
本研究的目的是调查生理和病理脑老化过程中的神经网络特征。分析了一个由378名参与者组成的数据库，这些参与者被分为三组：阿尔茨海默病（AD）、轻度认知障碍（MCI）和正常老年人（Nold）。通过脑电图记录，使用sLORETA软件评估皮质源，同时计算无向加权网络的图论参数（特征路径长度λ、聚类系数γ和小世界网络σ），该网络由eLORETA软件评估的滞后线性相干性获得。频谱分析的脑电图皮质源在δ、θ和α1频段显示出显著差异。此外，eLORETA皮质连接性分析表明，对于归一化特征路径长度（λ），在θ频段观察到正常认知与痴呆之间的模式差异（MCI受试者与健康受试者相似），而对于归一化聚类系数（γ），AD组在δ、θ和α1频段有显著增加；最后，小世界（σ）参数在AD和MCI组之间呈现出显著的相互作用，显示MCI组的θ增加。AD患者和MCI受试者在θ频段而非α频段的连接性显著受损，这一事实与MCI在正常状态和明显痴呆之间处于中间状态的假设一致。
