P300在经颅直流电刺激对最小意识状态患者疗效评估中的应用：随机对照双盲研究

目的:利用P300评价经颅直流电刺激(tDCS)对最小意识状态(MCS)患者的疗效及可能的作用机制。方法:采用随机对照双盲的试验设计,将18例MCS患者随机分到真刺激组或假刺激组,真刺激组患者在连续10个工作日内接受20次左侧前额叶背外侧(DLPFC)区域tDCS刺激,假刺激组接受20次假刺激。在刺激前和20次刺激后两个时间点分别对患者进行改良昏迷恢复量表(CRS-R)行为学和事件相关电位(ERP)电生理学评估。结果:行为学结果表明,真刺激组MCS患者治疗后CRS-R总得分显著提高(P<0.05);ERP结果表明,真刺激组MCS患者治疗后P300波幅显著增加(P<0.05),而P300潜伏期未见明显变化(P>0.05)。结论:对MCS患者左侧DLPFC区域的重复tDCS刺激可改善其行为学表现,猜测可能是通过对关键脑区的刺激,加强了"自上而下"对"自下而上"注意过程的调控作用,从而增强了患者注意及以上认知资源的分配水平。

The application of P300 in evaluating therapeutic efficacy of transcranial direct current stimulation in patients with minimally conscious state

Objective:To assess the effects and potential mechanism of transcranial direct current stimulation(tDCS)in patients with minimally conscious state(MCS)by P300.Method:Using a sham-controlled randomized double-blind design,eighteen patients with MCS were randomly assigned to either real or sham stimulation group.The patients in the real stimulation group underwent 20 anodal tDCS sessions of the left dorsolateral prefrontal cortex(DLPFC)over 10 consecutive working days.The coma recovery scale-revised(CRS-R)score and event-related potential(ERP)were recorded to evaluate the consciousness level before tDCS and after the 20 sessions.Result:The CRS-R analysis revealed a clinically significant improvement in the MCS patients in the real stimulation group(P<0.05).The ERP analysis revealed a significant increase in P300 amplitude after tDCS in the MCS patients in the real stimulation group(P<0.05),but there was no significant increasement in P300 latency(P>0.05).Conclusion:The repeated anodal tDCS of the left DLPFC could produce clinically significant improvements in conscious state in MCS patients.The observed tDCS-related consciousness improvements might be related to enhancement in regulation of"top-down"to"bottom-up"attention process,and improvements in attention and cognitive resource allocation.