Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., USA.
Department of Psychiatry, University of Pittsburgh School of Medicine, USA.
Neuroimage Clin. 2020;28:102390. doi: 10.1016/j.nicl.2020.102390. Epub 2020 Aug 20.
Sleep disturbances are common complaints in patients with post-traumatic stress disorder (PTSD). To date, however, objective markers of PTSD during sleep remain elusive. Sleep spindles are distinctive bursts of brain oscillatory activity during non-rapid eye movement (NREM) sleep and have been implicated in sleep protection and sleep-dependent memory processes. In healthy sleep, spindles observed in electroencephalogram (EEG) data are highly synchronized across different regions of the scalp. Here, we aimed to investigate whether the spatiotemporal synchronization patterns between EEG channels during sleep spindles, as quantified by the phase-locking value (PLV) and the mean phase difference (MPD), are altered in PTSD. Using high-density (64-channel) EEG data recorded from 78 combat-exposed Veteran men (31 with PTSD and 47 without PTSD) during two consecutive nights of sleep, we examined group differences in the PLV and MPD for slow (10-13 Hz) and fast (13-16 Hz) spindles separately. To evaluate the reproducibility of our findings, we set apart the first 47 consecutive participants (18 with PTSD) for the initial discovery and reserved the remaining 31 participants (13 with PTSD) for replication analysis. In the discovery analysis, compared to the non-PTSD group, the PTSD group showed smaller MPDs during slow spindles between the frontal and centro-parietal channel pairs on both nights. We obtained reproducible results in the replication analysis in terms of statistical significance and effect size. The PLVs during slow or fast spindles did not significantly differ between groups. The reduced inter-channel phase difference during slow spindles in PTSD may reflect pathological changes in the underlying thalamocortical circuits. This novel finding, if independently validated, may prove useful in developing sleep-focused PTSD diagnostics and interventions.
睡眠障碍是创伤后应激障碍（PTSD）患者常见的主诉。然而，迄今为止，睡眠期间 PTSD 的客观标志物仍难以捉摸。睡眠梭形波是在非快速眼动（NREM）睡眠期间大脑振荡活动的独特爆发，并且与睡眠保护和睡眠依赖的记忆过程有关。在健康的睡眠中，脑电图（EEG）数据中观察到的梭形波在头皮的不同区域之间具有高度的同步性。在这里，我们旨在研究睡眠梭形波期间 EEG 通道之间的时空同步模式是否在 PTSD 中发生改变，这些模式通过锁相值（PLV）和平均相位差（MPD）来量化。使用从连续两个晚上的睡眠中记录的 78 名经历过战斗的男性退伍军人（31 名患有 PTSD，47 名没有 PTSD）的高密度（64 通道）EEG 数据，我们分别检查了慢（10-13 Hz）和快（13-16 Hz）梭形波的 PLV 和 MPD 的组间差异。为了评估我们发现的可重复性，我们将前 47 名连续参与者（18 名患有 PTSD）分离出来进行初步发现，并保留其余 31 名参与者（13 名患有 PTSD）进行复制分析。在发现分析中，与非 PTSD 组相比，在两个晚上，PTSD 组在前额和中央顶叶通道对之间的慢梭形波中显示出较小的 MPD。在复制分析中，我们在统计学意义和效应大小方面获得了可重复的结果。慢或快梭形波期间的 PLV 在组间没有显着差异。在 PTSD 中，慢梭形波期间的通道间相位差减小可能反映了基础丘脑皮质回路的病理性变化。如果独立验证，这一新颖的发现可能有助于开发以睡眠为重点的 PTSD 诊断和干预措施。
