[REM Sleep Behavior Disorder and α-synucleinopathy].

REM sleep behavior disorder (RBD) can progress to Parkinson's disease, Lewy body dementia, or multiple system atrophy within 20 years of onset. Accurate diagnosis of RBD is therefore important for early intervention. The development of markers that can more sensitively evaluate the effects of high-risk groups or candidate therapies that develop α-synucleinopathy in the short term is the key to a successful clinical trial. Clinical protocols for early diagnosis of α-synucleinopathy are currently being developed. The next stage will be to conduct clinical trials for candidate therapies.