Vol.:(0123456789) 1 3 Clinical Autonomic Research https://doi.org/10.1007/s10286-018-0557-4 RESEARCH ARTICLE Heart rate variability in Parkinson disease and idiopathic REM sleep behavior disorder Paulo Bugalho 1,2  · Marcelo Mendonça 1,2  · Tânia Lampreia 1  · Rita Miguel 1  · Raquel Barbosa 1  · Manuel Salavisa 1 Received: 26 April 2018 / Accepted: 10 August 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Purpose Heart rate variability, a marker of autonomic function modulation, is known to be blunted in Parkinson disease, although data remains conficting and a putative modifying role of REM sleep behavior disorder persists unclarifed. 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 vari- ability 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 diferences between Parkinson disease and idiopathic REM sleep behavior disorder groups. There were signifcant 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. Keywords Heart rate variability · Parkinson disease · REM sleep behavior disorder Introduction Heart rate variability (HRV), a surrogate marker of auto- nomic system modulation, was found to be blunted in patients with Parkinson disease (PD) [1–6]. Some doubts persist regarding the type of autonomic dysfunction, and its relation with sleep stage and association with rapid eye movements (REM) sleep behaviour disorder (RBD). While some studies have shown a predominant afection of the sympathetic nervous system (SNS) [3, 4, 6], others have found signs of both SNS and parasympathetic nervous sys- tem (PNS) dysfunction [1, 2], depending on sleep stage [2], or motor dysfunction severity [1]. Some studies evaluated HRV only in the wake state [3], while others assessed polysomnography sleep data, fnding diferences between REM and non-REM stages [1, 4, 5]. Reduction in heart rate response to arousals or periodic limb movements was documented in idiopathic RBD (iRBD) [5]. Some studies have shown reduction in the variation of SNS modulated variables, more signifcantly in wake stages and in patients with PD compared to patients with iRBD [6]. Others found a reduction in very low and low frequencies components in iRBD compared to controls [7]. Lanfranchi et al. found an attenuation in normal HRV increase between NREM and REM stages in patients with iRBD compared to controls, afecting high and low frequency components as well as respiratory frequency [8]. Valappil and collaborators found that HRV during wakefulness was signifcantly decreased in patients with idiopathic REM sleep behavior disorder com- pared with control subjects, suggesting abnormalities of both sympathetic and parasympathetic function [9]. Some authors have suggested that HRV reduction could be specifc for RBD, and not PD [3]. Others, however, have found altera- tions both in patients with PD with RBD (PD–RBD) and * Paulo Bugalho paulobugalho@sapo.pt 1 Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental (CHLO), Rua da Junqueira, 126, 1349-019 Lisbon, Portugal 2 CEDOC, Chronic Diseases Research Center, NOVA Medical School, Lisbon, Portugal