强迫症患者的事件相关脑电位实验研究

背景 强迫症在辅助诊断上目前还缺乏客观的实验室依据。近年来国内外对强迫症的事件相关脑电位进行了研究，结果并不一致。分析其主要原因与所使用仪器、技术性能有关。为此本研究使用国际标准化的美国Nicolet脑电生理仪，并以较成熟的关联性负变、P300及失匹性负波3种事件相关脑电位为手段，并设临床上较多见的抑郁症和广泛性焦虑症为疾病对照，进一步探讨强迫症的脑电生理机制，为临床诊断及治疗提供参考依据。 方法 应用美国Nicolet Spirit 脑诱发电位仪,采用光和声成对刺激以及“听觉靶-非靶刺激序列”技术，对38例强迫症、20例抑郁症和18例广泛性焦虑症及28名正常人的关联性负变(CNV)、P300及失匹性负波(MMN)作了检测。3组疾病组病例均选自2002年5月至2005年12月上海市精神卫生中心，经2名以上的高年资医师确诊并符合中国精神障碍分类方案第三版（CCMD-3）中的强迫症和抑郁症及广泛性焦虑症诊断标准；听力均正常，并无躯体疾病或其他精神疾病，均为右利手。3组对象均未使用过精神科药物。结果 ①CNV：M1波幅抑郁症组(5±4)μV]和广泛性焦虑症组(7±4)μV]低于正常组(14±6)μV]和强迫症组(16±6)μV，指令信号后负变化的出现率抑郁症组(60%)、强迫症组(45%)和广泛性焦虑症组(35%)均高于正常组(4%)，上述组间差异均有统计学意义（P<0.05或P<0.01）。②P300：在靶刺激中，N2潜伏期在4组间的差异有统计学差异(P<0.01)，其中强迫症组(276±22)ms]和抑郁症组(277±22)ms]的潜伏期均长于正常组(259±14)ms]，广泛性焦虑症组短于抑郁症组和强迫症组(P<0.01)；P3波幅在4组间的差异亦有统计学差异(P<0.01)，其中强迫症组(3.4士1.6)μV]、抑郁症组(2.9±1.3)μV]和广泛性焦虑症组(3.3士1.3)μV]均低于正常组(5.9土2.1)μV]。在非靶刺激中，广泛性焦虑症组P2波幅低于强迫症组和正常组(P<0.05)。③MMN：强迫症组、抑郁症组及正常组之间潜伏期和波幅的差异有统计学差异(P<0.05或P<0.01)。其中强迫症组和抑郁症组的潜伏期长于正常组(P<0.05)；强迫症组的波幅高于正常组(P<0.05)，抑郁症组的波幅低于正常组(P<0.05)和强迫症组(P<0.01)。结论 ERPs波幅一高一低变异特点可能对鉴别强迫症和抑郁症有参考意义。

An experimental study of event-related potentials in obsessive compulsive disorder

Objective In order to investigate the variations of contingent negative variations (CNV), P300 & mismatch negative( MMN) of obsessive compulsive disorder, major depression disorder & generalized anxiety disorder, the present study was initiated. Methods Three event-related potentials CNV, P300 & MMN was recorded from 38 cases of obsessive compulsive disorder using a Nicolet Spirit Instrument, and was compared with that of 28 normal controls, 20 major depression disorder controls, and 18 generalized anxiety disorder controls. Results A significant difference of CNV among 4 subject groups was found in both PINV and amplitudes (M1)(P<0.01)(emergence of PINV were 44%,60%,33%, and 4% in obsessive compulsive disorder, major depression disorder, generalized anxiety disorder, and normal control groups respectively). Compared with normal control group, major depression disorder group and generalized anxiety disorder group showed decreased M1 amplitude (P<0.01). And a significant difference of P300 among 4 subject groups was found in both latencies (Cz/N2) and P3 and nontarget-P2 amplitudes (P<0.05~0.01). The MMN presentation of obsessive compulsive disorder and major depression disorder was similar to that of P300 changes. Conclusion The characteristics of ERPs of those patients might be useful indexes in distinguishing obsessive compulsive disorder from major depression disorder.