Status dissociatus evolving from REM sleep behaviour disorder in multiple system atrophy

ObjectiveWe present two patients, a 52-year-old man and a 56-year-old woman, with rapid eye movement sleep behaviour disorder (RBD) since the age of 50.MethodIn both the patients RBD was videopolysomnographically documented.ResultsBoth patients developed, with time, autonomic and motor symptoms consistent with the diagnosis of multiple system atrophy. During the course of the disease RBD episodes diminished in frequency but the patients’ sleep became even more abnormal, with nearly continuous motor and verbal abnormal behaviours and ambiguous and rapid oscillations of state-determining polysomnographic variables, now consistent with status dissociatus (SD).ConclusionIf SD represents the evolution and most extreme form of RBD it should be investigated longitudinally in neurodegenerative diseases.