Abstract
α-synucleinopathies are a complex group of progressive neurodegenerative disorders
with an increasingly recognized long prodromal period, during which sleep dysfunction
is a hallmark. Sleep disorders during the prodromal synucleinopathy period, primarily
isolated rapid eye movement (REM) sleep behavior disorder (iRBD) and daytime hypersomnolence
correlate best with the recently proposed “body-first” Lewy body disease progression.
iRBD is the most widely recognized form of prodromal α-synucleinopathy, and patients
with iRBD show abnormal α-synuclein in tissues and biofluids even in the absence of
cognitive or motor symptoms. More importantly, individuals with iRBD have an elevated
risk for near-term development of a clinically diagnosable symptomatic synucleinopathy.
Other sleep disorders such as hypersomnia and circadian rhythm dysfunction also occur
across the synucleinopathy spectrum, although their prognostic significance is less
well understood than iRBD. Finally, isolated REM sleep without atonia may represent
an even earlier stage of prodromal synucleinopathy, but further studies are needed.
Keywords
prodromal - synucleinopathy - REM sleep behavior disorder - Circadian Rhythm
