基于脑电谱分析的轻度认知功能障碍患者脑功能变化的三年随访研究

Changes of Brain Function in Patients With Mild Cognitive Impairment: Results of A 3-year Follow-up Study

目的探讨轻度认知功能障碍（MCI）患者脑功能随时间在神经心理学和神经生理学方面的变化特征。方法选取2009年9月—2010年4月在天津医科大学总医院神经内科就诊的具有记忆障碍主诉的MCI患者11例作为MCI组,征集性别、年龄、受教育年限均与之匹配的健康老年人14例作为HC组。分别于入选时和3年后对受试者进行简易智力状态检查量表（MMSE）、临床记忆量表（CMS）和综合医院焦虑抑郁量表（HADS）评分;并采用数字化脑电记录系统,分别采集MCI组及HC组3年前后脑电信号。在Matlab 7.0平台上利用自编程序按以下的频率范围分别计算各频带功率：δ频带（2-4 Hz）,θ频带（4-8 Hz）,α频带（8-13 Hz）,β频带（13-30 Hz）和γ频带（〉30 Hz）,并计算α相对功率比（αRPP）。结果入选时和3年后,两组等值记忆商（MQ）、指向记忆、联想学习、图像自由回忆、无意义图形再认、人像特点联系回忆评分比较,差异均无统计学意义（P〉0.05）;3年后,两组指向记忆、无意义图形再认评分均低于入选时,MCI组联想学习评分低于入选时（P〈0.05）。入选时,MCI组全脑、左半球、左额区、左颞区、左中央区、左顶区、左枕区αRPP均低于HC组（P〈0.05）;3年后,MCI组全脑、左半球、左颞区、左中央区、左枕区αRPP均低于HC组（P〈0.05）。3年后,两组全脑、左半球、右半球、左额区、右额区、左颞区、右颞区、左中央区、右中央区、左顶区、右顶区、左枕区、右枕区αRPP均低于入选时（P〈0.05）。入选时,MCI右半球、右额区、右颞区、右中央区、右顶区、右枕区αRPP均高于对侧（P〈0.05）。结论 CMS中联想学习分测验得分可能是区分MCI和增龄性老化的敏感神经心理学指标。随着时间推进,MCI患者和正常老年人均出现増龄性脑功能减退,但MCI脑功能改变以优势半球功能受损更为显著,且出现更早,随病程进展可出现明显非优势半球功能减退。

Objective To explore the changes of neurophysiological and neuropsychological indicators in patients with mild cognitive impairment（ MCI） by 3 years＇ follow-up. Methods This study enrolled 11 patients with MCI and subjective memory impairment who received treatment in neurology department in the General Hospital of Tianjin Medical University from September,2009 to April,2010 as MCI group,and recruited another 14 healthy old people as HC group matched in gender,age,and years of schooling. The subjects underwent mini-mental state examination（ MMSE）,clinical memory scale（ CMS）and hospital anxiety and depression scale（ HADS）. EEG investigations were conducted to record the after brain electrical signal of the two groups at baseline and the end of the three years. Power of each band was calculated by self-compiled program in Matlab 7. 0 within following ranges： δ band（ 2-4 Hz）,θ band（ 4-8 Hz）,α band（ 8-13 Hz）,β band（ 13-30 Hz）and γ band（ 〉30 Hz）. Alpha relative power percentage（ αRPP） of EEG was then calculated. Results At baseline and the end of the three years, the two groups had no significant differences（ P〈0. 05） in the score of MQ, directional memory,associative learning,free graphic memory,meaningless graphic recognition and portrait characteristics memory. At the end of the three years,the two groups in the scores of directional memory and meaningless graphic recognition were lower than that of at baseline（ P〈0. 05）, the scores of associative learning of MCI group were lower than that of HC group（ P〈0. 05）. At baseline,αRPP in whole brain,left brain,left frontal region,left temporal region,left central region,left parietal region and left occipital region of MCI group was lower than that of HC group（ P〈0. 05）. At the end of the three years,αRPP in whole brain,left brain,left temporal region,left central region,left occipital region of MCI group was lower than that of HC group（ P〈0. 05）. At the end of the three years,the two groups αRPP in whole brain,left brain,right brain,left frontal region,right frontal region,left temporal region,right temporal region,left central region,right central region,left parietal region,right parietal region,left occipital region and right occipital region were lower than that of at baseline（ P〈0. 05）. At baseline,the MCI group of αRPP in right brain,right frontal region,right central region,right parietal region and right occipital region were higher than that of contralateral（ P〈0. 05）. Conclusion The score in associative learning subtest of CMS may be a sensitive indicator to distinguish MCI from aging. The function of cerebrum shows a loss by age in both MCI and HC. However,MCI subjects show more serious and earlier hypofunction than HC subjects in the dominant hemisphere,and obvious hypofunction may also emerge in the nondominant hemisphere as MCI worsening.