Claudia Trenkwalder, MD, University Medical Center of Göttingen, Göttingen, Germany, discusses the progression of REM sleep behavior disorder (RBD) from the prodromal stages to definite RBD and RBD in a neurodegenerative disorder. Prodromal symptoms of RBD which are not yet sufficient to fulfill the diagnostic criteria for isolated RBD have recently been demonstrated. Within a matter of years, these patients will go on to develop RBD, followed by neurodegenerative disease in many. Thus, identifying these symptoms and intervening at this very early stage is critical. RBD is known to be a strong risk marker for Parkinson’s disease but may also represent a progression marker. The prevalence of RBD, as well as REM sleep without atonia, increases as Parkinson’s disease advances. This suggests the neurodegenerative process in Parkinson’s involves brain regions responsible for REM sleep regulation and RBD may be a progression marker. This interview took place during the European Academy of Neurology 2021 congress.