Missonnier Pascal, Gold Gabriel, Herrmann François R, Fazio-Costa Lara, Michel Jean-Pierre, Deiber Marie-Pierre, Michon Agnès, Giannakopoulos Panteleimon
Neuroimaging Unit, University Hospitals of Geneva, Geneva, Switzerland.
Dement Geriatr Cogn Disord. 2006;22(3):250-9. doi: 10.1159/000094974. Epub 2006 Aug 10.
Among the different quantitative electroencephalographic markers, theta activity is known to reflect neural resources involved in memory processes and directed attention. Previous studies suggested that synchronization likelihood analysis in theta-band frequency might be a sensitive method to identify early alterations of neuronal networks in mild cognitive impairment (MCI).
We report here a longitudinal study of 24 MCI patients with theta event-related synchronization (ERS) analysis during the n-back working memory task and neuropsychological follow-up after 1 year. Statistical analysis included analysis of variance and logistic regression to assess the relationship between cognitive decline and theta ERS.
Upon follow-up, 13 MCI patients showed progressive MCI and 11 remained stable. In both groups, the phasic increase in theta amplitude after stimulus presentation did not depend on working memory load and electrode sites. Progressive MCI cases displayed significantly lower theta ERS power over all electrode sites compared to stable MCI cases. Theta ERS was significantly related to the cognitive outcome explaining 15.5% of its variability. In terms of MCI classification, the best combination of sensitivity and specificity was 0.87 and 0.60, respectively, with an area under the corresponding receiver operating characteristic curve reaching 76%.
The present data indicate that a decrease in the early phasic theta ERS power during working memory activation may predict cognitive decline in MCI. This phenomenon is not related to working memory load but may reflect the presence of early deficits in directed attention-related neural circuits in MCI.
在不同的定量脑电图标记物中，已知θ波活动可反映参与记忆过程和定向注意力的神经资源。先前的研究表明，θ频段频率的同步可能性分析可能是一种识别轻度认知障碍（MCI）中神经网络早期改变的敏感方法。
我们在此报告一项对24名MCI患者的纵向研究，在n-back工作记忆任务期间进行θ事件相关同步（ERS）分析，并在1年后进行神经心理学随访。统计分析包括方差分析和逻辑回归，以评估认知衰退与θ ERS之间的关系。
随访时，13名MCI患者出现进行性MCI，11名保持稳定。在两组中，刺激呈现后θ波幅的相位增加不依赖于工作记忆负荷和电极部位。与稳定的MCI病例相比，进行性MCI病例在所有电极部位的θ ERS功率显著降低。θ ERS与认知结果显著相关，解释了其变异性的15.5%。就MCI分类而言，敏感性和特异性的最佳组合分别为0.87和0.60，相应的受试者工作特征曲线下面积达到76%。
目前的数据表明，工作记忆激活期间早期相位θ ERS功率的降低可能预测MCI中的认知衰退。这种现象与工作记忆负荷无关，但可能反映了MCI中定向注意力相关神经回路早期缺陷的存在。
