Progression and prognosis in multiple system atrophy presenting with REM behavior disorder

To investigate (1) the prevalence of REM sleep behavior disorder (RBD) as mode of disease onset in a cohort of patients with multiple system atrophy (MSA) and (2) disease progression and prognosis in patients with MSA with RBD predating (pre-RBD) and following (post-RBD) disease onset.We retrospectively identified all patients with a clinical diagnosis of MSA evaluated at least once a year during the disease course. Type of onset was defined by the first reported motor or autonomic symptom/sign related to MSA. The occurrence of symptoms/signs and milestone of disease progression, and their latency from disease onset, were collected. Survival data were calculated. RBD was confirmed by video-polysomnography.Of a total of 158 patients, pre-RBD represented the mode of disease onset in 27% of patients, preceding disease onset according to the international criteria with a median of 3 (2-5) years. Comparing pre-RBD and post-RBD patients, the first group showed an increased prevalence of autonomic onset of disease, a reduced prevalence of parkinsonism, an earlier onset of stridor, pyramidal signs, symptomatic orthostatic hypotension, urinary dysfunction, severe dysphagia, and wheelchair dependency. The risk of death was higher in patients with pre-RBD.In our MSA cohort, RBD represented the most frequent mode of disease presentation. A more rapid progression of disease was observed in the pre-RBD group. These findings suggested a careful assessment of sleep disorders to early recognize RBD and a closer follow-up of autonomic dysfunction and stridor in patients with pre-RBD.