Introduction to the special issue on RBD 40 years old: Perspectives on extensive clinical and research intersections

This Introduction to the special issue in Sleep Medicine marking the 40th anniversary of the first publication on REM sleep behavior disorder (RBD) in 1986 provides a brief historical background with early timelines, followed by current RBD and REM-without-atonia diagnostic considerations; and updates on RBD global epidemiology, RBD in younger populations, and the spectrum of RBD comorbidities and biomarkers. Other topics covered include RBD gut microbiome dysbiosis, proteome abnormalities, and neuroinflammation; RBD international research consortia; RBD economic burden and adverse quality of life; and neurodegeneration risk disclosure for newly diagnosed idiopathic/isolated RBD patients. Thirty-four RBD clinical and research intersections are depicted in a figure. Two recent review articles are cited that identified more than 4200 peer-reviewed journal articles published to date on RBD. The six articles contained in this special RBD issue cover animal models and basic science; genetics; pathogenesis; measurement and diagnosis; neurodegeneration, neuroimaging, and phenoconversion biomarkers; and cognition. RBD epitomizes the close collaboration and cross-fertilization of clinical and basic science research.