事件相关诱发电位对阿尔茨海默病与轻度认知功能障碍的诊断价值

Diagnostic value of event-related potentials in Alzheimer's disease and mild cognitive impairment.

目的探讨事件相关诱发电位(event-related potentials,ERPs)对阿尓茨海默病(Alzheimer's disease,AD)和轻度认知功能障碍(mild cognitive impairment,MCI)的诊断价值。方法前瞻性的研究130例受试者,分3组:AD组60例,MCI组35例,和正常对照组(normal control,NC)35名,均进行神经及神经心理检查,功能评定,神经影像检查并记录事件相关诱发电位(ERPs),包括感觉(N1,P2)及认知(N2,P3)事件诱发电位。分析ERPs指标与神经心理检查和认知障碍严重程度的相关性,比较各组ERPs的变化及其诊断价值。结果 ERPs在各组有显著差异,与NC组相比,AD及MCI组N2、P3潜伏期延长和波幅降低具有显著差异P<0.001;在AD和MCI组间,P3潜伏期及波幅在两组间有统计学差异(P<0.05);N2、P3潜伏期与神经心理检查呈负相关,相关系数为-0.24～-0.403,P<0.01,与痴呆的严重程度正相关;N2,P3的潜伏期对鉴别AD及NC有一定价值,P3潜伏期344 ms时,敏感性约80%,特异性较高98%。N2潜伏期235 ms时,敏感性和特异性分别为73.3%及71.4%。鉴别AD与MCI时,P3潜伏期345 ms时,敏感性约80%,特异性较低50%。鉴别MCI与NC时,N2及P3潜伏期在234 ms及326 ms时,诊断的敏感性及特异性在60%～70%。结论事件相关电位与认知功能及痴呆的严重程度明显相关,可以客观,量化的反映AD和MCI患者的认知功能。P3指标对临床诊断AD和MCI有一定价值。

Objective To evaluated the diagnostic value of event-related evoked potentials（ERPs） in Alzheimer＇s disease（AD） and mild cognitive impairment（MCI）.Methods we prospectively studied 130 subjects,which were classified into three groups,60 dementia of Alzheimer type,35 MCI,and 35 control subjects,they all underwent neurological and neuropsychological examination,functional evaluation,neurological imaging and recorded event-related evoked potentials（ERPs）,including sensory（N1,P2） and cognitive（N2,P3） event evoked potential.Correlation was analyzed between ERPs and the neuropsychological test and severity of cognitive impairment.Compared the changes of ERPs and evaluated the diagnostic value of ERPs in each groups.Results ERPs were significantly different between the groups.Compared to the NC,AD and MCI patients have longer latencies of N2,P3,and lower amplitude of P3,P0.001;Between AD and MCI group,latency and amplitude of P3 is difference,P0.05;N2,P3 latencies were negatively correlated to the neuropsychological scores,r=-0.24～-0.403,P0.05,and positively correlated to the severity of cognitive impairment;Furthermore,N2,P3 can help identify AD and NC,P3 latency cut-off values as 344 ms,sensitivity was 80%,and specificity was 98%;P3 latency can help identify AD and MCI,P3 latency cut-off values as 345 ms,sensitivity was about 80%,and specificity was 50%;N2 latency cutoff value was 344 ms,sensitivity and specificity was 73.3% and 71.4% respectively.N2,P3 latencies cut-off value was 234ms and 326ms,the diagnostic sensitivity and specificity were between 60%～70% to identify MCI with NC.Conclusions There are significant relationship between ERPs and cognitive function and dementia severity,suggesting that ERPs can objectively reflect cognitive impairment in patients with AD and MCI.ERPs can serve as physiological index in diagnosis of AD and MCI.