Background. The reduced amplitude, prolonged latency, and increased intertrial variability of auditory P300 have been consistently reported in relation to the symptomatic severity of schizophrenia. This study investigated whether auditory P300 event-related potentials can be used as an objective indicator of symptomatic improvement by transcranial direct current stimulation (tDCS) in patients with schizophrenia. Methods. Ten patients with schizophrenia received 20 minutes of 2-mA tDCS twice a day for 5 consecutive weekdays. The anode was placed over the left dorsolateral prefrontal cortex, and the cathode was placed over the left temporo-parietal cortex. The Positive and Negative Syndrome Scale (PANSS) and the auditory P300 were measured for each participant at baseline and after the completion of the tDCS applications. Results. The participants showed significant improvement in the positive and negative symptoms as indexed by change in the PANSS scores by the tDCS. The P300 amplitude, latency, and intertrial variability did not statistically significantly differ after the tDCS application. However, a significant association was observed between the reduced P300 intertrial variability and improvement in the positive symptoms by tDCS. In addition, the changes in both the P300 latency and intertrial variability were significantly correlated with reduced negative symptoms after the tDCS application. Conclusions. Although this pilot study is limited by the small sample size and lack of a sham control, the results suggest that auditory P300 may be a putative marker reflecting the effect of tDCS on the positive and negative symptoms of schizophrenia.

中文翻译：

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听觉 P300 作为精神分裂症患者经颅直流电刺激症状改善的神经生理相关因素：一项初步研究

背景。听觉 P300 的振幅降低、潜伏期延长和试验间变异性增加一直被报道与精神分裂症的症状严重程度有关。本研究调查了听觉 P300 事件相关电位是否可用作精神分裂症患者经颅直流电刺激 (tDCS) 症状改善的客观指标。方法。10 名精神分裂症患者连续 5 个工作日每天两次接受 20 分钟的 2-mA tDCS。阳极置于左背外侧前额叶皮层上方，阴极置于左侧颞顶叶皮层上方。在基线和完成 tDCS 应用程序后，测量了每位参与者的阳性和阴性综合征量表 (PANSS) 和听觉 P300。结果。根据 tDCS PANSS 分数的变化，参与者的阳性和阴性症状都有显着改善。tDCS 应用后，P300 振幅、潜伏期和试验间变异性在统计学上没有显着差异。然而，观察到 P300 试验间变异性降低与 tDCS 阳性症状改善之间存在显着关联。此外，P300 潜伏期和试验间变异性的变化与 tDCS 应用后阴性症状的减少显着相关。结论。虽然这项试点研究受到样本量小和缺乏假控制的限制，但结果表明听觉 P300 可能是一个推定的标记，反映了 tDCS 对精神分裂症阳性和阴性症状的影响。