Dysregulation, disease or degeneration of these nuclei can result in sleep disorders, such as narcolepsy, and subtle changes to sleep-wake patterns. The behavioral states of wake and sleep are initiated and maintained by complex interplay between multiple brainstem and diencephalic nuclei. The mechanisms behind this fluctuation remains unknown. In any one patient, the severity and frequency of the behaviors may also vary from night to night, and over the course of their condition ( 10). The frequency of motor events may vary greatly between RBD individuals ranging from multiple episodes per night, to one episode per month ( 9). Upon awakening from a large motor event, the RBD individual will be alert and orientated to their surroundings ( 4). When a dream enactment is occurring, the individual's eyes will remain closed as they engage with the dream environment and their movements are generally contained to their immediate surroundings, thus differentiating these episodes from NREM parasomnias such as sleepwalking ( 4).

More systematic studies have revealed that violent dreams and behaviors only make up a small percentage of all events ( 6– 8). Whilst accounts of individuals kicking, punching, biting, or even strangling their bedpartners during sleep paint an emotive image of the condition and often capture public interest, they are prone to recall bias. As acute dream enactment is generally self-limiting, the chronicity of symptoms (>6 months) is a key distinguishing factor, and forms part of the diagnostic criteria for RBD ( 4).Īnecdotally, dreams are often reported by patients with RBD as violent or aggressive, resulting in violent motor behaviors which may pose a threat to them or their bedpartner ( 5). In contrast, RBD individuals will maintain REM sleep during and immediately after most of their dream enactments. In non-pathological dream enactment, individuals typically respond to dream content during the transition from REM sleep to the awake state and while maintaining REM atonia during much of the REM period. The same symptoms may also be experienced during withdrawal from sedatives or alcohol. It is important to remember that dream enactment and limb movements during sleep can occur in the healthy population, often in the context of heightened emotional states ( 1– 3).

Here, individuals experience vivid dreams which they act out during sleep. Whilst isolated RSWA is frequently an incidental finding in sleep studies, it forms the substrate of the dream enactment behavior which defines RBD. This phenomenon is often referred to as REM Sleep without Atonia (RSWA). Rapid Eye Movement (REM) Sleep Behavior Disorder (RBD) is a non-familial sleep disorder, characterized by the loss of the inherent muscle atonia observed during normal REM sleep. We aim to raise awareness and develop a framework for best practice for RBD patient management. 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. Both clinicians and patients are therefore forced to deal with uncertain outcomes. There are no binary prognostic markers for RBD disease course and there are no clinical guidelines for neurodegeneration scaling or tracking in these patients. Uncertainty in patient management is further exacerbated by a lack of clinical guidelines for RBD patient care. The disease's low prevalence and the relatively limited awareness of the condition amongst medical professionals makes the diagnosis and treatment of RBD challenging. RBD patients also exhibit accelerated disease progression and a more severe phenotype than α-synucleinopathy sufferers without RBD. 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. Individuals often present to clinic with complaints of injury to themselves or their bed-partner due to violent movements during sleep. REM Sleep Behavior Disorder (RBD) is a chronic sleep condition characterized by dream enactment and loss of REM atonia.

4Translational Health Sciences, University of Bristol, Bristol, United Kingdom.

3Department of Neurology, Southmead Hospital, Bristol, United Kingdom.

2Rosa Burden Centre, Southmead Hospital, Bristol, United Kingdom.

1School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.

Deep sleep disorder treatment