Fide Ezgi, Yerlikaya Deniz, Güntekin Bahar, Babiloni Claudio, Yener Görsev G
Department of Neurosciences, Institute of Health Sciences, Dokuz Eylul University, Izmir, Turkey.
Department of Biophysics, School of Medicine, Istanbul Medipol University, Istanbul, Turkey.
Cogn Neurodyn. 2023 Dec;17(6):1621-1635. doi: 10.1007/s11571-022-09920-0. Epub 2022 Dec 17.
Working memory performances are based on brain functional connectivity, so that connectivity may be deranged in individuals with mild cognitive impairment (MCI) and patients with dementia due to Alzheimer's disease (ADD). Here we tested the hypothesis of abnormal functional connectivity as revealed by the imaginary part of coherency (ICoh) at electrode pairs from event-related electroencephalographic oscillations in ADD and MCI patients. The study included 43 individuals with MCI, 43 with ADD, and 68 demographically matched healthy controls (HC). Delta, theta, alpha, beta, and gamma bands event-related ICoh was measured during an oddball paradigm. Inter-hemispheric, midline, and intra-hemispheric ICoh values were compared in ADD, MCI, and HC groups. The main results of the present study can be summarized as follows: (1) A significant increase of midline frontal and temporal theta coherence in the MCI group as compared to the HC group; (2) A significant decrease of theta, delta, and alpha intra-hemispheric coherence in the ADD group as compared to the HC and MCI groups; (3) A significant decrease of theta midline coherence in the ADD group as compared to the HC and MCI groups; (4) Normal inter-hemispheric coherence in the ADD and MCI groups. Compared with the MCI and HC, the ADD group showed disrupted event-related intra-hemispheric and midline low-frequency band coherence as an estimate of brain functional dysconnectivity underlying disabilities in daily living. Brain functional connectivity during attention and short memory demands is relatively resilient in elderly subjects even with MCI (with preserved abilities in daily activities), and it shows reduced efficiency at multiple operating oscillatory frequencies only at an early stage of ADD.
The online version contains supplementary material available at 10.1007/s11571-022-09920-0.
工作记忆表现基于大脑功能连接，因此在轻度认知障碍（MCI）个体和阿尔茨海默病（ADD）所致痴呆患者中，这种连接可能会紊乱。在此，我们检验了如下假设：ADD和MCI患者事件相关脑电图振荡电极对处的相干性虚部（ICoh）所揭示的功能连接异常。该研究纳入了43名MCI个体、43名ADD患者以及68名人口统计学匹配的健康对照（HC）。在奇偶数范式期间测量了δ、θ、α、β和γ频段事件相关ICoh。比较了ADD、MCI和HC组的半球间、中线和半球内ICoh值。本研究的主要结果可总结如下：（1）与HC组相比，MCI组中线额叶和颞叶θ相干性显著增加；（2）与HC组和MCI组相比，ADD组半球内θ、δ和α相干性显著降低；（3）与HC组和MCI组相比，ADD组中线θ相干性显著降低；（4）ADD组和MCI组半球间相干性正常。与MCI和HC相比，ADD组显示出事件相关半球内和中线低频段相干性破坏，这可作为日常生活中功能障碍潜在的脑功能失调的一种估计。即使是患有MCI（日常生活能力保留）的老年受试者，在注意力和短期记忆需求期间的脑功能连接也相对有弹性，并且仅在ADD的早期阶段，其在多个操作振荡频率下的效率才会降低。
网络版包含可在10.1007/s11571-022-09920-0获取的补充材料。
