REM Sleep Behavioral Events and Dreaming

Abstract

Study Objectives: To clarify whether motor behaviors and/ or vocalizations during REM sleep, which do not yet fulfi ll diagnostic criteria for REM sleep behavior disorder (RBD) and were defi ned as REM sleep behavioral events (RBEs), correspond to dream enactments. Methods: 13 subjects (10 patients with Parkinson disease [PD] and 3 healthy controls) originally identifi ed with RBE in a prospective study (DeNoPa cohort) were reinvestigated 2 years later with 2 nights of video-supported polysomnography (vPSG). The fi rst night was used for sleep parameter analysis. During the 2nd night, subjects were awakened and questioned for dream recall and dream content when purposeful motor behaviors and/or vocalizations became evident during REM sleep. REM sleep without atonia (RWA) was analyzed on chin EMG and the cutoff set at 18.2% as specifi c for RBD. Results: At the time of this investigation 9 of 13 subjects with previous RBE were identifi ed with RBD based upon clinical and EMG criteria. All recalled vivid dreams, and 7 subjects were able to describe dream content in detail. Four of 13 subjects with RBE showed RWA values below cutoff values for RBD. Three of these 4 subjects recalled having non-threatening dreams, and 2 (of these 3) were able to describe these dreams in detail. Conclusion: RBE with RWA below the RBD defi ning criteria correlate to dreaming in this selected cohort. There is evidence that RBEs are a precursor to RBD. 1 We found such phenomena in a cohort of de novo patients with Parkinson disease (PD) who had never been treated with medications for PD or RBD, as well as in age-and gender-matched healthy controls (DeNoPa cohort); we termed these phenomena REM sleep behavioral events (RBEs).2 RBEs have been proposed as a new sleep marker for PD and a possible precursor to RBD.2 Whereas RBD is understood as dream enacting behavior, the correlation of RBE to dream mentation has not yet been established. In the study presented here we sought to clarify whether or not RBE also represent dream enacting behaviors and if we can describe specific dream content during these events. METHODSThis study was conducted as an ancillary project to the DeNoPa Kassel study, a longitudinal prospective cohort study of nonmotor symptoms and biomarkers in PD. The design of the entire DeNoPa study, recruitment process and baseline results have been reported elsewhere. 2,3 REM Sleep Behavioral Events and Dreaming S C I E N T I F I C I N V E S T I G AT I O N S Patients and SubjectsWhen this ancillary project was conceived, 13 consecutive subjects (10 patients) from the DeNoPa cohort who showed RBE at baseline were available for re-investigation at their regular 2-year follow-up study visit with 2 nights of videosupported polysomnography (vPSG) (for demographic data see Tables 1A and 1B). At the time of the follow-up study, all 10 PD patients of this cohort were receiving dopaminergic medication. None of the subjects had ever received any medication for RBD. Sleep RecordingsThe fi rst night was documented without awakening and w...

Sleep in Parkinson’s disease

“…Most patients with RBE can recall dream content, and report nonviolent, non-threatening dreams. RBE subjects who at follow-up developed RBD reported more vivid and elaborate dreams [109].…”

“…Interestingly, there is increasing evidence that there may be prodromal stages of RBD, which manifest as minor jerks [91,100,108,109] or REM sleep without atonia [101]. Mollenhauer and co-workers found that even PD patients who did not yet meet the criteria for RBD had more movement during REM sleep [91], and Sixel-Döring and Trenkwalder denominated these seemingly purposeful movements "REM sleep behavioral events" (RBE) and demonstrated that they could represent another prodromal sign of RBD [100,108].…”

The Evolution of REM Sleep Behavior Disorder in Early Parkinson Disease

“…We presented preliminary evidence that these "REM behavioral events" (RBE) not fulfilling RBD defining criteria corresponded to dreaming suggesting that RBE may be a precursor to RBD. 9 We now present the two-year follow-up data to further clarify the role of RBE as a possible very early marker for neurodegeneration and investigate the progression of REM sleep associated behaviors.…”

Differentiating Oneiric Stupor in Agrypnia Excitata From Dreaming Disorders

“…Nightmares are often distinguished from bad dreams because the nightmares trigger an awakening whereas anxiety dreams are frightening dream experiences remembered only after waking up in the morning ( 123 ). Differently from RBD, during nightmares patients may vocalize or move minimally but complex motor behaviors with enacted dreams of defense against aggressions paralleling dream content usually are lacking ( 131 ). In addition, patients with nightmare disorder exhibit physiological REM atonia during polysomnography ( 85 ).…”