A Neurologist's Guide to REM Sleep Behavior Disorder

Abstract

REM Sleep Behavior Disorder (RBD) is a chronic sleep condition characterized by dream enactment and loss of REM atonia. Individuals often present to clinic with complaints of injury to themselves or their bed-partner due to violent movements during sleep. RBD patients have a high risk of developing one of the neurodegenerative α-synucleinopathy diseases: over 70% will develop parkinsonism or dementia within 12 years of their diagnosis. RBD patients also exhibit accelerated disease progression and a more severe phenotype than α-synucleinopathy sufferers without RBD. The disease's low prevalence and the relatively limited awareness of the condition amongst medical professionals makes the diagnosis and treatment of RBD challenging. Uncertainty in patient management is further exacerbated by a lack of clinical guidelines for RBD patient care. There are no binary prognostic markers for RBD disease course and there are no clinical guidelines for neurodegeneration scaling or tracking in these patients. Both clinicians and patients are therefore forced to deal with uncertain outcomes. In this review, we summarize RBD pathology and differential diagnoses, diagnostic, and treatment guidelines as well as prognostic recommendations with a look to current research in the scientific field. We aim to raise awareness and develop a framework for best practice for RBD patient management.

Keywords: Parkinson's disease; REMsleep behavior disorder (RBD); neurology; neuroscience; prodromal Parkinson's disease; sleep; sleep disorders.

Figure 1

Key brain regions and neurotransmitters involved in regulation and maintenance of the REM sleep stage under healthy normative or pathological RBD conditions. In RBD, dysfunction within the SubC → VMM → Spinal Motor Neuron pathway results in a lack of REM atonia (depicted with dotted line). BF, basal forebrain; LC, locus coeruleus; LDT/PPT, laterodorsal tegmentum/pedunculopontine tegmentum; LH, lateral hypothalamus; Subc/PC, subcoeruleus/pre-locus coeruleus; TMN, tuberomammillary nucleus; vlPAG, ventrolateral periaqueductal gray; VLPO/MnPO, ventrolateral preoptic nucleus/median preoptic nucleus; VMM, ventromedial medulla. Figure created using BioRender.com.

Figure 2

Flow chart summarizing the process of RBD diagnosis.