老年轻度认知功能损害的脑诱发电位变化及其发展为痴呆的预测因素

目的检测老年轻度认知功能损害（MCI）患者的脑诱发电位变化，探索其发展为痴呆的脑诱发电位预测因素。方法前瞻性对照研究。对象为患轻度认知功能损害的老年人（MCI组）和认知功能正常的老年人（NC组）两组。结果23例MCI和29例NC完成了基线脑诱发电位检查。与NC组相比，MCI组的听觉脑干反应波V绝对波幅和P300的P3靶波幅降低有统计学意义（P〈0．01）。多元逐步判别分析显示听觉脑干反应波V绝对波幅和P300的P3靶波幅的判别具有统计学意义（P〈0．01），两组判别总正确率为75％，但Logislic回归分析未发现脑诱发电位指标对MCI是否发展为痴呆有显著性预测作用。结论脑诱发电位检测有助于了解MCI的脑电生理变化，听觉脑干反应波V绝对波幅和P300的P3靶波幅的降低对MCI具有诊断价值。本研究未证实4种检测的脑诱发电位指标对预测MCI发展为痴呆有统计学意义。

MEASUREMENT OF BRAIN EVOKED POTENTIAL CHANGES AND THEIR PREDICTIVE VALUE OF MILD COGNITIVE IMPAIRMENT IN THE ELDERLY

Objective To examine the changes of brain evoked potentials of mild cognitive impairment(MCI)in the elderly and to explore their predictive factors for MCI to convert into dementia.Methods A cross-sectional and longitudinal parallel cohort study design was adopted.Subjects were divided into two groups,the elderly with mild cognitive impairment(MCI)and normal controls(NC).The brain evoked potentials including brainstem evoked response(ABR),contingent negative variation(CNV),event related potential P300(ERP)and visual evoked potential(VEP)were assessed at baseline and their predictive capability was analyzed.Results The brain evoked potentials of 23 MCI and 29 NC were assessed at baseline.Compared with the NC group,the elderly with MCI showed significantly decreased amplitudes of ABR wave V and P3 of P300((P < 0.01).A linear discriminant function was obtained with stepwise discriminant analysis and variables of wave V and P3 provided a discriminative accuracy of 75%,but Logistic analysis demonstrated that no variables of brain evoked potentials showed significant predictive capability for MCI converting into dementia.Conclusions Brain evoked potentials are helpful in understanding the brain bio-electric changes of the elderly with mild cognitive impairment and that decreased absolute amplitudes of wave V and P3 are valuable in diagnosis of MCI but it seems that they are not significant predictive factors for MCI converting into dementia