Department of Neurology, School of Medicine, Technical University of Munich (TUM), Munich, Germany.
TUM-Neuroimaging Center, School of Medicine, TUM, Munich, Germany.
Pain. 2021 Dec 1;162(12):2894-2908. doi: 10.1097/j.pain.0000000000002281.
Chronic pain is a highly prevalent and severely disabling disease that is associated with substantial changes of brain function. Such changes have mostly been observed when analyzing static measures of resting-state brain activity. However, brain activity varies over time, and it is increasingly recognized that the temporal dynamics of brain activity provide behaviorally relevant information in different neuropsychiatric disorders. Here, we therefore investigated whether the temporal dynamics of brain function are altered in chronic pain. To this end, we applied microstate analysis to eyes-open and eyes-closed resting-state electroencephalography data of 101 patients suffering from chronic pain and 88 age- and sex-matched healthy controls. Microstate analysis describes electroencephalography activity as a sequence of a limited number of topographies termed microstates that remain stable for tens of milliseconds. Our results revealed that sequences of 5 microstates, labelled with the letters A to E, consistently described resting-state brain activity in both groups in the eyes-closed condition. Bayesian analysis of the temporal characteristics of microstates revealed that microstate D has a less predominant role in patients than in controls. As microstate D has previously been related to attentional networks and functions, these abnormalities might relate to dysfunctional attentional processes in chronic pain. Subgroup analyses replicated microstate D changes in patients with chronic back pain, while patients with chronic widespread pain did not show microstates alterations. Together, these findings add to the understanding of the pathophysiology of chronic pain and point to changes of brain dynamics specific to certain types of chronic pain.
慢性疼痛是一种高发且严重致残的疾病，与大脑功能的实质性变化有关。这些变化主要是在分析静息状态下大脑活动的静态测量时观察到的。然而，大脑活动是随时间变化的，人们越来越认识到大脑活动的时间动态在不同的神经精神障碍中提供了与行为相关的信息。在这里，我们因此研究了慢性疼痛是否会改变大脑功能的时间动态。为此，我们应用微状态分析对 101 名患有慢性疼痛的患者和 88 名年龄和性别匹配的健康对照者的睁眼和闭眼静息态脑电图数据进行了分析。微状态分析将脑电图活动描述为一系列数量有限的被称为微状态的拓扑结构，这些拓扑结构可以稳定数十毫秒。我们的结果表明，在闭眼状态下，两组人群的静息态大脑活动都可以用 5 个微状态（用字母 A 到 E 表示）的序列来描述。微状态时间特征的贝叶斯分析表明，微状态 D 在患者中的作用不如在对照组中明显。由于微状态 D 先前与注意网络和功能有关，这些异常可能与慢性疼痛中的注意力过程功能障碍有关。亚组分析在慢性背痛患者中复制了微状态 D 的变化，而慢性广泛性疼痛患者则没有显示微状态的改变。总之，这些发现增加了对慢性疼痛病理生理学的理解，并指出了特定类型的慢性疼痛中大脑动力学的变化。
