Jiang Zheng-yan, Zheng Lei-lei
Department of Psychiatry, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.
J Zhejiang Univ Sci B. 2006 May;7(5):357-64. doi: 10.1631/jzus.2006.B0357.
To assess functional relationship by calculating inter- and intra-hemispheric electroencephalography (EEG) coherence at rest and during a working memory task of patients with mild cognitive impairment (MCI).
The sample consisted of 69 subjects: 35 patients (n=17 males, n=18 females; 52-71 years old) and 34 normal controls (n=17 males, n=17 females; 51~63 years old). Mini-mental state examination (MMSE) of two groups revealed that the scores of MCI patients did not differ significantly from those of normal controls (P>0.05). In EEG recording, subjects were performed at rest and during working memory task. EEG signals from F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 electrode pairs are resulted from the inter-hemispheric action, and EEG signals from F3-C3, F4-C4, C3-P3, C4-P4, P3-O1, P4-O2, T5-C3, T6-C4, T5-P3 and T6-P4 electrode pairs are resulted from the intra-hemispheric action for delta (1.0-3.5 Hz), theta (4.0-7.5 Hz), alpha-1 (8.0-10.0 Hz), alpha-2 (10.5-13.0 Hz), beta-1 (13.5-18.0 Hz) and beta-2 (18.5-30.0 Hz) frequency bands. The influence of inter- and intra-hemispheric coherence on EEG activity with eyes closed was examined using fast Fourier transformation from the 16 sampled channels.
During working memory tasks, the inter- and intra-hemispheric EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group (P<0.05). However, there was no significant difference in inter- and intra-hemispheric EEG coherences between two groups at rest.
Experimental results comprise evidence that MCI patients have higher degree of functional connectivity between hemispheres and in hemispheres during working condition. It suggests that MCI may be associated with compensatory processes during working memory tasks between hemispheres and in hemispheres. Moreover, failure of normal cortical connections may exist in MCI patients.
通过计算轻度认知障碍（MCI）患者静息状态及工作记忆任务期间的半球间和半球内脑电图（EEG）相干性来评估功能关系。
样本包括69名受试者：35例患者（17例男性，18例女性；年龄52 - 71岁）和34名正常对照者（17例男性，17例女性；年龄51 - 63岁）。两组的简易精神状态检查表（MMSE）显示，MCI患者的得分与正常对照者无显著差异（P>0.05）。在EEG记录中，受试者在静息状态和工作记忆任务期间进行检测。来自F3 - F4、C3 - C4、P3 - P4、T5 - T6和O1 - O2电极对的EEG信号源于半球间活动，而来自F3 - C3、F4 - C4、C3 - P3、C4 - P4、P3 - O1、P4 - O2、T5 - C3、T6 - C4、T5 - P3和T6 - P4电极对的EEG信号源于半球内活动，针对δ（1.0 - 3.5 Hz）、θ（4.0 - 7.5 Hz）、α1（8.0 - 10.0 Hz）、α2（10.5 - 13.0 Hz）、β1（13.5 - 18.0 Hz）和β2（18.5 - 30.0 Hz）频段。使用快速傅里叶变换从16个采样通道检查闭眼状态下半球间和半球内相干性对EEG活动的影响。
在工作记忆任务期间，与对照组相比，MCI组所有频段的半球间和半球内EEG相干性均显著更高（P<0.05）。然而，两组在静息状态下的半球间和半球内EEG相干性无显著差异。
实验结果证明，MCI患者在工作状态下半球间和半球内具有更高程度的功能连接。这表明MCI可能与工作记忆任务期间半球间和半球内的代偿过程有关。此外，MCI患者可能存在正常皮质连接的缺失。
