目的:高清晰度经颅直流电刺激(HD-tDCS)已成为治疗意识障碍(DOC)的有效神经刺激方法。然而,HD-tDCS的作用和机制尚不清楚。
方法:这项研究招募了8名DOC患者,并连续14天使用2mAHD-tDCS(Pz处的中央阳极电极)20分钟。我们在四个时间点记录DOC患者的EEG数据和昏迷恢复量表修订(CRS-R)值:基线(T0),顶叶HD-tDCS治疗后1天和7,14天(T1,T2,T3)。功率谱密度(PSD),相对功率(RP),计算频谱熵和频谱指数,以评估DOC患者在长期顶叶HD-tDCS过程中的EEG动态变化。最后,我们计算了EEG特征变化与CRS-R值变化之间的相关性。
结果:顶叶HD-tDCS后1天,DOC患者的CRS-R值无变化(8.25±1.91)。HD-tDCS在T2(9.75±1.91,p<0.05)和T3(11.38±2.77,p<0.05)时改善了DOC患者的CRS-R值,与T0时相比(8.25±1.91)。随着治疗时间的增加,脑电图PSD衰减更慢。具体来说,δ频带RP下降,而阿尔法,beta,伽马频带RP增加。T1时脑电振荡特征改变但不显著(p>0.05),在T2和T3时显示出显着变化(p<0.05)。从T0到T3,谱熵连续增加,谱指数连续减小。具体来说,顶叶和枕骨区的谱熵和谱指数在T2和T3时均明显高于T0时(p<0.05)。此外,顶叶和枕叶的EEG特征的变化与CRS-R值的变化相关,特别是在T2和T0之间。
结论:长期顶叶HD-tDCS可以改善DOC患者的意识水平和脑活动。静息状态脑电图可以评估HD-tDCS过程中DOC患者大脑活动的动态变化。EEG振荡和非振荡活动可用于解释HD-tDCS对DOC患者的作用机制。
OBJECTIVE: High-definition transcranial direct current stimulation (HD-tDCS) has been an effective neurostimulation method in the treatment of disorders of consciousness (DOC). However, the effects and mechanism of HD-tDCS are still unclear.
METHODS: This study recruited 8 DOC patients and applied 20-min sessions of 2 mA HD-tDCS (central anode electrode at Pz) for 14 consecutive days. We record DOC patients\' EEG data and Coma Recovery Scale-Revised (CRS-R) values at four time point: baseline (T0), after 1 day\'s and 7,14 days\' parietal HD-tDCS treatment (T1, T2, T3). Power spectral density (PSD), relative power (RP), spectral entropy and spectral exponent were calculated to evaluate the EEG dynamic changes of DOC patients during long-term parietal HD-tDCS. At last, we calculated the correlation between changes of EEG features and changes of CRS-R values.
RESULTS: After 1 day\'s parietal HD-tDCS, DOC patients\' CRS-R value had not changed (8.25 ± 1.91). HD-tDCS improved DOC patients\' CRS-R value at T2 (9.75 ± 1.91, p < 0.05) and at T3 (11.38 ± 2.77, p < 0.05), compared with that at T0 (8.25 ± 1.91). As the treatment time increased, the EEG PSD decayed more slowly. Specifically, the delta frequency band RP decreased, while the alpha, beta, and gamma frequency bands RP increased. EEG oscillation characteristics changed but not significant at T1 (p > 0.05), and showed significant changes at T2 and T3 (p < 0.05). The spectral entropy continuously increased and the spectral exponent continuously decreased from T0 to T3. Specifically, the spectral entropy and spectral exponent of the parietal and occipital regions were significantly higher at T2 and T3 than that at T0 (p < 0.05). In addition, The changes in EEG features of the parietal and occipital lobes were correlated with changes in CRS-R value, especially between T2 and T0.
CONCLUSIONS: Long-term parietal HD-tDCS can improve the consciousness level and brain activity in DOC patients. Resting-state EEG can evaluate the dynamic changes of brain activity in DOC patients during HD-tDCS. EEG oscillation and non-oscillatory activity might be used to explain the mechanism of HD-tDCS on DOC patients.