Cardiac autonomic denervation in Parkinson's disease is linked to REM sleep behavior disorder

Recent studies have suggested a close connection between autonomic dysfunction and rapid eye movement sleep behavior disorder, which differs in nature from other early-stage markers of Parkinson's disease. In this study we examined the relationship between rapid eye movement sleep behavior disorder and autonomic dysfunction in Parkinson's disease as measured by cardiac beat-to-beat variability.

In 53 patients with Parkinson's disease and 36 controls, electrocardiographic trace from a polysomnogram was assessed for measures of beat-to-beat RR variability including RR-standard deviation and frequency domains (low- and high-frequency components). Results were compared between patients with Parkinson's disease and controls, and between patients with Parkinson's disease with and without rapid eye movement sleep behavior disorder.

On numerous cardiac autonomic measures, patients with Parkinson's disease showed clear abnormalities compared with controls. However, these abnormalities were confined only to those patients with associated rapid eye movement sleep behavior; those without were not different than controls.

As with other clinical autonomic variables, cardiac autonomic denervation is predominantly associated not with Parkinson's disease itself, but with the presence of rapid eye movement sleep behavior disorder.