Rapid Eye Movement (REM) is a sleep behaviour disorder classified under DSM-5 in sleep disorders. This disorder causes to physically play out vivid and frequently unpleasant dreams. That is, during the REM stage of sleep, rather than the usual temporary state of paralysis of arms and legs (atonia), the dreams are enacted physically. This physical enactment is referred to as dream-enacting behaviour. The symptoms of this disorder include violent movements, noises such as shouting or laughing and good recall of dreams. The prevalence rate of REM sleep behaviour disorder (RBD) is estimated to be around 0.5 to 1.25 per cent approximately with most diagnoses occurring in middle-to-older age adults. Among older adults, RBD is estimated to be prevalent at around 2 per cent approx.
This study provides a detailed model of the disorder’s progression. According to this study, RBD may be due to neurodegeneration linked with the specific effect of tauopathy on sleep. The authors also reported the early biomarkers of imminent tauopathy and the effects of ageing on sleep physiology. The most important contribution of the study is that it provides a newer treatment option that has fewer side effects.
Highlights of the Study
A group of researchers from Mount Sinai Hospital, USA discovered a new method of treatment for RBD. This treatment has been said to affect more than 3 million Americans mostly of age over 50. Who experience the violent effects of dream-enacting behaviors.
This study doesn’t only outline the characteristics of RBD. Also proposes a new model for the development of the disorder. According to this model, neurodegeneration- the process of loss of function of the brain cells over time- in connection with an accumulation of tau protein impacts RBD development.
Based on Andrew W. Varga, the study provides an understanding of all. How neurodegeneration impacts sleep quality and the ways to deal with these changes. In addition, this model provides the signs of the sleep EEG signature that acts as part of early-life biomarkers indicating brain deterioration. This could act as a guide for future prevention and treatment.
Current trends for the treatment of RBD, include the use of Klonopin, which causes side effects such as dizziness, disturbed sleep, and muscle weakness. This is a high-risk medication that exposes its users to risks of abuse, misuse and addiction. Thus, this study also suggests that sleep medications called dual orexin receptor antagonists can be an effective treatment option for RBD. This medication helps commonly to deal with insomnia and has potentially fewer side effects compared to Klonopin.
To provide the above findings, Mount Sinai researchers used a mouse model to observe abnormal deposits of tau protein. This tau protein helps stabilize the internal skeleton of the nerve cells in the brain.
They also analyzed the behavioural states of the participants such as the stages of sleep (both REM and Non-REM), wakefulness, duration of sleep, transitions during sleep and the relationship with age. Most of the older subjects displayed dream-enacting behaviours such as chewing and limb extension.
The individuals were given dual orexin receptor antagonists twice during a 24-hour period by the researchers. Later it was observed the medication helped to reduce the time. It took to fall asleep and improved the duration and quality of sleep. It was also reported that it reduced the levels of dream-enacting behaviours. With these findings, the researchers hope to encourage future trials of these medications for RBD.