2021 年 38 巻 4 号 p. 508-511
Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by dream enactment behaviors. Patients often experience unpleasant dreams with anger or fear, such as “fighting” or “being chased by a bear,” and often experience violent movement and injury related to the dream. RBD has been recognized as a precursor to neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. In the treatment of RBD, it is necessary not only to deal with dream enactment behaviors but also to consider the future progression to neurodegenerative diseases.
Polysomnography is essential for the diagnosis of RBD, and REM without atonia is important for RBD diagnosis.
In a systematic review and meta–analysis of RBD longitudinal studies, the progression rate from idiopathic RBD to neurodegenerative diseases (phenoconversion) was 33.5% at five years, 82.4% at 10.5 years, and 96.6% at 14 years from the first visit.
As non–pharmacological interventions for dream enactment behaviors, it is vital to make a bedroom environment safe. Coping with stress and reducing alcohol consumption are also effective. As for medication, clonazepam is effective in most cases but has a risk of confusion and falls. Ramelteon and Yokukansan (Yi–Gan San) have been reported to be useful for dream enactment behaviors in RBD.
There is insufficient evidence for therapeutic interventions in the long–term course of RBD. To improve the quality of treatment for RBD comorbid with Parkinson's disease or dementia with Lewy bodies, it is necessary to conduct a survey and establish the evidence about the incidence of injury due to dream enactment behaviors and adverse drug effects.
