基于ROC曲线的精神分裂症诊断性P300界值的确定

Diagnostic P300 threshold based on the analysis of receiver operating characteristic curve

目的探讨P300波幅和潜伏期的受试者工作特征曲线（ROC曲线）在精神分裂症诊断中的应用。方法选择2009年7月至2012年6月的上海市精神卫生中心91例首次发作精神分裂症（FES）患者与141名健康人P300波幅和潜伏期数据绘制ROC曲线，计算P300波幅及潜伏期诊断精神分裂症时约登指数及ROC曲线中的距离变化情况，确立最佳诊断点，并对被试按性别及年龄分层后，提高诊断的准确性。结果P300波幅预测精神分裂症时ROC曲线下面积为0．746（P〈0．001），P300潜伏期对于精神分裂症的预测则较差（P=0．373）；以P300波幅=5．097μV为诊断点，对精神分裂症预测的敏感度和特异度分别为80．14％和63．74％；按性别及年龄分层后，各类人群的诊断点有不同程度的变化，且P300波幅在所有5类人群中诊断结果的约登指数均有所提高（1．80％-14．88％）；分层诊断能明显提高男性（25．01％）、25岁以下（22．22％）、40岁以上人群（28．80％）诊断指标的敏感度。结论P300波幅在精神分裂症诊断中具有一定的意义，根据性别和年龄等影响因素进行分层，可以提高ROC曲线在高发人群中的诊断效能。

Objective To explore the diagnostic application of receiver operating characteristic （ROC） curve of P300 amplitude and latency in schizophrenia. Methods ROC curve of P300 amplitude and latency was plotted from 91 first episode schizophrenia （FES） and 141 normal controls （NC）. Youden＇s index and distance were calculated in ROC curve to determine the optimal cutoff point of P300 amplitude and latency for schizophrenic diagnosis. Then the subjects were layered by gender and age for improved diagnostic accuracy. Results The area under ROC curve for P300 amplitude for predicting schizophrenia was 0.746 （ P 〈 0. 001 ）, while P300 latency showed poor power in predicting schizophrenia （ P = 0. 373 ）. The optimal cutoff point of P300 amplitude was 5. 097 μV with a sensitivity of 80.14% and a specificity of 63.74%. After gender and age stratification, Youden＇ s index was enhanced in all 5 subgroups （from 1.8% to 14.88% ） and the sensitivities of corresponding cutoff were enhanced obviously in subgroups of males （25.01%）, ≤25 years （22.22%） and 〉40 years （28.80%） patients. Conclusion P300 amplitude has certain values in schizophrenic diagnosis. Gender and age stratification may enhance the diagnostic efficiency of ROC curve in the diagnosis of frequent schizophrenia.