Polysomnographic diagnosis of REM sleep behavior disorder: a change is needed

Abstract

We welcome the remarks by Ferri and colleagues regarding the practical application of the International rapid eye movement (REM) sleep Behavior Disorder (RBD) Study Group (IRBDSG) video-polysomnography (vPSG) guidelines for RBD diagnosis. As highlighted in their letter, the rich body of literature continuously confirming isolated RBD (iRBD) as a neurodegenerative disease in the prodromal phase is based on polysomnography (PSG)-confirmed RBD cases, underlying the “necessary objective role played by the PSG.” Starting from this shared view, we would like to drive attention to the fact that the list of concerns raised by Ferri et al. (with the exception of point 8) also applies to the current ICSD-3 criteria for RBD and for other sleep disorders, for example, narcolepsy [1]. No return to the previous ICSD-2 criteria is desirable, as it is clear that mimics [2, 3] and unawareness of disease [4] make a diagnosis of RBD based on clinical history not possible.