Objective:  To describe the first reported case of behavioral and phasic neurophysiological activity during slow-wave sleep (SWS) in a patient with symtomatic REM sleep behavior disorder (RBD).  

Background: REM sleep is characterized by a constellation of phasic events mediated by ponto-mesencephalic structures. To our knowledge, phasic activity has not been previously reported during SWS.

Methods: We analyzed the behavioural and polygraphic sleep features evolution of symtomatic RBD in a Parkinson disease patient.

Results: A 64-years-old male with idiopathic Parkinson disease was initially referred for the presence of motor-behavioral episodes (MBEs) emerging during the second half of night (including vocalizations, punching, yelling, smiling and laughing) consistent with symptomatic RBD. At the age 68, two consecutive video-PSGs demonstrated the normal cyclic NREM and REM sleep macrostructure features co-existing with dissociated REM sleep (REM sleep without atonia) and dissociated NREM sleep aspects, with intrusion of REM sleep phasic activities into NREM stages (namely, polymorphic isolated or clustered REMs, sometimes associated with muscle twitching, MBEs and breathing pattern irregularities). MBEs were not associated with tachycardia and included jerky/simple movements, unintelligible vocalizations and purposeful movements suggesting RBD-like dream-enacting behaviors. Cognitive status examination was unremarkable, except for a mild apathy and executive dysfunction. On motor status, under 344.5 mg of levodopa equivalent dose, Hoehn-Yahr score was 3 and UPDRS-III score was 31. 

Conclusions: The unusual NREM muscle twitching and MBEs mirrored the intrusion of RBD-like phasic activity of REM into NREM sleep, considering the dissociative behaviors phenomenology, clustering pattern and absence of autonomic reactivity to NREM sleep MBEs. This is the first case showing RBD-like MBEs during scorable SWS, which differed from previous cases of status dissociatus evolving from an RBD substrate in which continuous nocturnal MBEs were associated with breakdown of state-determining boundaries. This case suggests that in normal individuals, phasic motor activity and behaviors during NREM sleep are actively blocked. Our case may represent an intermediary stage between RBD, parasomnia overlap disorder and status dissociatus, during which the disintegration of state-determining markers gradually converges to a simultaneous admixture of all stages.

« Back to 2017 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/phasic-activity-during-non-rem-sleep/