Objective

Resting-state EEG microstate is a promising neurophysiological tool to explore the temporal dynamics of cognitive activity. Till now, the microstate syntax is far from being fully understood in mild cognitive impairment (MCI) and Alzheimer’s disease (AD). We aim to investigate the possible explanation for the alterations of transition probabilities in microstate syntax between different stages of cognitive impairment.

Methods

The artefact-corrected resting-state EEG in patients with MCI (n = 46), AD (n = 43) and healthy controls (HC, n = 43) were used for microstate analysis. Four microstates were labeled A-D according to the study (Koenig et al., 2002).

Results

Microstate duration, occurrence and coverage showed overall differences between HC, MCI and AD. Duration and coverage B increased significantly in AD compared with HC and MCI. Coverage C decreased significantly in AD compared with MCI. Microstate syntax had specialized single transitions in MCI and AD. Transitions between symmetrical (C and D) and asymmetrical (A and B) classes showed a decreased pattern. It was only in MCI that an increased transition from A to C was found and only in AD an increased transition from A to B was found. Besides, a negative spearman’s correlation was found between the transition probability from A to B and Mini-Mental State Examination (MMSE) scores.

Conclusion

Altered resting-state EEG microstates in particular specialized single transitions in microstate syntax were showed in MCI and AD.

Significance

For the first time, we discovered which single transitions between pairs of microstates play an important role in microstate syntax in different stages of cognitive impairment.

中文翻译：

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轻度认知障碍和阿尔茨海默病的脑电图微状态动态改变

客观的

静息态 EEG 微状态是一种很有前途的神经生理学工具，可用于探索认知活动的时间动态。到目前为止，在轻度认知障碍 (MCI) 和阿尔茨海默病 (AD) 中，微状态句法还远未完全理解。我们的目的是研究认知障碍不同阶段之间微状态句法转换概率变化的可能解释。

方法

MCI（n = 46）、AD（n = 43）和健康对照（HC，n = 43）患者的人工校正静息态脑电图用于微观状态分析。根据研究，四种微观状态被标记为 AD（Koenig 等，2002）。

结果

微观状态持续时间、发生率和覆盖率显示出 HC、MCI 和 AD 之间的总体差异。与 HC 和 MCI 相比，AD 的持续时间和覆盖率 B 显着增加。与 MCI 相比，AD 的覆盖率 C 显着降低。微状态语法在 MCI 和 AD 中有专门的单一转换。对称（C 和 D）和不对称（A 和 B）类别之间的过渡显示出减少的模式。仅在 MCI 中发现从 A 到 C 的过渡增加，并且仅在 AD 中发现从 A 到 B 的过渡增加。此外，在从 A 到 B 的转换概率与简易精神状态检查 (MMSE) 分数之间发现了负矛头相关性。

结论

在 MCI 和 AD 中显示了改变的静息状态 EEG 微状态，特别是微状态句法中专门的单一转换。

意义

我们第一次发现，在认知障碍的不同阶段，微状态对之间的哪些单一转换在微状态句法中起着重要作用。