中文摘要：

目的 采用事件相关电位（event-related potential，ERP）及低分辨率电磁断层成像（low resolution brain electromagnetic tomography，LORETA）技术，研究轻度认知损害患者冲突信息处理系统的损害机制及敏感指标。方法 研究对象为15例轻度认知损害（AMO）患者（AMCI组）和15例年龄、性别、受教育年限匹配的正常老年（正常老年组）作为对照。成对的简单平面图形先后呈现，受试者比较刺激对是否相同，同时记录32导脑电、正确反应率及反应时间。结摹刺激匹配状态下两组的P300波形分布均以顶部为著，潜伏期及波幅无显著差异。刺激冲突状态下N270主要分布在前头部，AMCI组N270潜伏期较正常老年组明显延长（F1．28=25．3264，P=0．000），波幅差异不显著。LORETA电流密度分析显示冲突状态下正常老年组前头中央部、左右前额背外侧及右颞叶激活，AMCI组右前额背外侧及右颞叶区域激活增强，前头中央部无明显激活。脑电地形图分析与上述结果相一致。结论 前头部ERP成分N270峰潜伏期延长反映了轻度认知损害患者信息加工处理速度减慢，患者对冲突状态信息加工处理的损害较匹配状态信息加工处理的损害更为明显。

英文摘要：

Objective To find a sensitive index and to investigate the mechanism of the conflict process impairment in patient with mild cognitive impairment. Methods Fifteen patients with mild cognitive impairment and 15 healthy matched aged controls performed a matching-to-sample task while event-related potential （ERP）, reaction time and correct reaction rate were recorded. Subjects were required to press one or another button in the match/conflict condition. Results In the matched condition, there was no difference between the two groups in distribution（parietal lobe）, peak latency and amplitude of P300. In the conflict condition, the N270 was mainly distributed at forehead, its latency in patient group was delayed as compared with that in the aged control group（ F1.28 .= 25.3264, P = 0.000）, but its amphtude showed no significant change. Source localization analysis by Low Resolution Electromagnetic tomography （LORETA） showed that the brain activated under conflict condition in control group were central part of forehead, left and right frontal dorsolateml part and right temporal lobe. In the patient group, the degree of activation in conflict condition was distinctly increased at the right frontal dorsolateral area and right temporal lobe, while there was no obvious activation of central part of forehead. Condusion The change of N270 component reflects the step down of information processing speed in patient with mild cognitive impairment. The impairment of conflict information processing in mild cognitive impairment is more significant than that of the matched information processing.