Center for Sleep Medicine, Division of Pulmonology, Department of Medical Specialties, Geneva University Hospitals, Geneva, Switzerland; Department of Neuroscience, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland.
Laboratory of Cognitive Neuroscience, Center for Neuroprosthetics and Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland.
Neuroimage Clin. 2019;22:101701. doi: 10.1016/j.nicl.2019.101701. Epub 2019 Jan 29.
Nightmares are characterized by the experience of strong negative emotions occurring mainly during REM sleep. Some people suffer from nightmare disorder, which is defined by the repeated occurrence of nightmares and by significant distress in wakefulness. Yet, whether frequent nightmares relate to a general increase in emotional reactivity or arousal during sleep remains unclear. To address this question, we recorded heartbeat-evoked potentials (HEPs) during wakefulness, NREM and REM sleep in patients with nightmare disorder and healthy participants. The HEP represents a cortical (EEG) response to the heartbeat and indexes brain-body interactions, such as interoceptive processing and intrinsic levels of arousal. HEP amplitude is typically increased during states of high emotional arousal and motivation, and is decreased in depression. Here we compared the amplitude of HEPs between nightmare patients and healthy controls separately during AWAKE, NREM, REM periods, and found higher HEP amplitude in nightmare patients compared to healthy controls over a cluster of frontal regions only during REM sleep. This effect was not paralleled by any group difference in cardiac control measures (e.g. heart rate variability, interbeat interval). These findings corroborate the notion that nightmares are essentially a REM pathology and suggest that increased emotional arousal during REM sleep, as measured by HEP, is a physiological condition responsible for frequent nightmares. This result also supports that HEP may be used as a biomarker of increased emotional and sensory processing during REM sleep in these patients.
梦魇的特征是在快速眼动（REM）睡眠期间主要经历强烈的负面情绪。有些人患有梦魇障碍，其定义是反复出现梦魇和在清醒时出现明显痛苦。然而，频繁的梦魇是否与睡眠期间情绪反应或唤醒的普遍增加有关仍不清楚。为了解决这个问题，我们在梦魇障碍患者和健康参与者清醒、非快速眼动（NREM）和快速眼动（REM）睡眠期间记录了心跳诱发电位（HEPs）。HEP 是大脑对心跳的皮质（EEG）反应，可反映脑-体相互作用，如内脏处理和内在唤醒水平。HEP 幅度通常在情绪唤醒和动机高的状态下增加，在抑郁时降低。在这里，我们分别比较了梦魇患者和健康对照组在清醒、NREM 和 REM 期之间的 HEP 幅度，发现在 REM 睡眠期间，仅在前额区域的一簇中，梦魇患者的 HEP 幅度明显高于健康对照组。这种效应与心率变异性、心动间隔等心脏控制措施的任何组间差异无关。这些发现证实了梦魇本质上是一种 REM 病理学的观点，并表明 REM 睡眠期间 HEP 测量的情绪唤醒增加是导致频繁梦魇的生理状况。这一结果还支持 HEP 可作为这些患者 REM 睡眠期间情绪和感觉处理增加的生物标志物。
