Non-REM parasomnias: a scoping review of dreams and dreamlike mentation

Abstract

Aim To establish patterns or themes of dreams and dreamlike mentation content reported in all forms of non-rapid eye movement (NREM) parasomnias and to identify gaps in the current understanding of this topic. Methods A scoping review of available evidence on dreams and dreamlike mentation in NREM parasomnias was conducted in accordance with the PRISMA-ScR guidelines. We searched peer-reviewed literature using Google Scholar, PubMed, Ovid (Embase), Ovid Medline®, Global Health, and APA Psych Info. The Mixed Method Appraisal Tool (MMAT) was used to appraise the quality of selected articles. Results The final analysis included 16 studies. All of the studies were from high-income countries. The studies reported on dreams and dreamlike mentation in NREM parasomnias, but there was scarcity of literature for sexsomnia, sleep-related eating disorder, and confusional arousal. All of the studies had the highest quality as shown by the MMAT (76%-100%). Emotions such as apprehension and misfortune were associated with sleepwalking and sleep terrors. Conclusion Sleep studies involving collection of dream content immediately following NREM parasomnia could significantly minimize reporting bias and improve dream data quality.

Dreaming Characteristics in Non-Rapid Eye Movement Parasomnia and Idiopathic Rapid Eye Movement Sleep Behaviour Disorder: Similarities and Differences

“…Previously, we and others have suggested that the subconscious processing of external environmental cues during NREMP episodes may promote discontinuity and ambiguity in the mental imagery of dreamers. 5,9,10,43 In this NREMP cohort, however, dream recall may have been further affected by significant sleep fragmentation, as evidenced by a higher arousal index compared to iRBD patients. Moreover, as shown in Figure 2, the NREMP reports in our study demonstrate high convolution and recursiveness, thought-like dreams, and confusion regarding the chronology of events.…”

“… 11–13 Excessive daytime sleepiness is frequently reported by NREM parasomnia sufferers, as well as lower threshold for pain and poorer quality of life. 9 , 13 …”

“…5,6 Moreover, recent evidence suggests that limited dreaming arising from NREM sleep may occur because of interfering phasic bursts or REM-like sleep microstructure. [7][8][9][10][11] These phasic events have been linked to series of metabolically demanding physiologic events including contractions of the middle ear muscles, rapid eye movements, myoclonic twitches of skeletal muscles, sawtooth waves, irregularities in cardiorespiratory activity, and ponto-geniculo-occipital waves. 12 Thus, phasic REM sleep likely plays a distinct role in dreaming.…”

“…14 In this context, parasomnias have historically attracted the interest of sleep experts due to distinct sleep behaviors associated with dream mentation, and specific perceptual and sensory experiences. 15,16 More specifically, sleep parasomnias, such as NREM parasomnia (NREMP) 5,9,17,18 and (idiopathic) REM sleep Behavior Disorder (iRBD), 19,20 exemplify a rare opportunity to gain a direct insight into dream activity and mentation. 1,6,16,21 Parasomnias are associated with distinct sleep states/stages, but they can also occur during sleep wake transitions.…”

“…[11][12][13] Excessive daytime sleepiness is frequently reported by NREM parasomnia sufferers, as well as lower threshold for pain and poorer quality of life. 9,13 Understanding how basic physiological components of sleep may contribute to the genesis of dreams will be pivotal for future translational clinical purposes. 1,7,21,32 However, it is widely accepted that oneiric research is significantly limited by an inaccessible nature of dreams, where any insight on intrinsic dream activity depends on retrospective recall by dreamers.…”