A case series of REM sleep behavior disorder in pure autonomic failure.

PURPOSE: Data on the prevalence of RBD in patients with PAF are limited, with discrepancies in the literature regarding prevalence. We aimed to provide further data on this association with a series of eight patients with PAF.

METHODS: We reviewed the electronic medical records of all patients seen at the Stanford neurology clinics from 2012 to 2016 who were given a provisional diagnosis of PAF (343 patients), and further screened by procedure codes to identify those patients who underwent both attended video-polysomonography and autonomic testing (18 patients), and met strict exclusionary criteria (8 patients).

RESULTS: The mean age of our patients was 69 years, and 63 % were women. The mean duration of autonomic symptoms was 11.2 years, and the mean duration of dream enactment was 3.75 years. All patients demonstrated evidence of adrenergic failure on autonomic testing. Five out of 8 (63 %) met diagnostic criteria for RBD, confirmed on vPSG.

CONCLUSIONS: Our series supports the concept that RBD in PAF may be more common than previously reported, and that the presence of RBD suggests brainstem involvement in some cases of PAF. In addition, the timing of RBD symptoms relative to the emergence of autonomic symptoms may be useful to help distinguish these conditions.