Heart rate variability in Parkinson disease and idiopathic REM sleep behavior disorder

Purpose: Heart rate variability, a marker of autonomic function modulation, is known to be blunted in Parkinson disease, although data remains conflicting and a putative modifying role of REM sleep behavior disorder persists unclarified. Methods: We assessed ten patients with idiopathic REM sleep behavior disorder patients, 18 patients with Parkinson disease and REM behavior disorder and eight patients with Parkinson disease without REM sleep behavior disorder. Heart rate variability analysis was performed in 5-min epochs selected from wake, Non-REM and REM polysomnography records. We compared heart rate variability measures by stage between two sets of groups: Parkinson disease vs. idiopathic RBD and patients with vs. without RBD, by using repeated measures ANOVA. Results: There were no heart rate variability differences between Parkinson disease and idiopathic REM sleep behavior disorder groups. There were significant stage vs. group interactions (p = 0.045) regarding the high frequencies components when comparing patients with and without REM sleep behavior disorder, with the former presenting lower values and attenuation of sleep stage variations. Conclusion: Our study suggests that RBD is related with reduction in parasympathetic modulation of heart rate variability and blunting of sleep stage related variations.