Increased Motor Activity During REM Sleep Is Linked with Dopamine Function in Idiopathic REM Sleep Behavior Disorder and Parkinson Disease.
STUDY OBJECTIVES Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by impaired motor inhibition during REM sleep, and dream enacting behavior. RBD is especially associated with a synucleinopathies, such as Parkinson disease (PD) Follow up studies have shown that patients with idiopathic RBD (iRBD) have an increased risk of developing an a synucleinopathy in later life. Although abundant studies have shown that degeneration of the nigrostriatal dopaminergic system is associated with daytime motor function in Parkinson disease, only few studies have investigated the relation between this system and electromyographic (EMG) activity during sleep. The objective of this study was to investigate the relationship between the nigrostriatal dopamine system and muscle activity during sleep in iRBD and PD. METHODS 10 iRBD patients, 10 PD patients with PD, 10 PD patients without RBD, and 10 healthy controls were included and assessed with (123)I N omega fluoropropyl 2 beta carboxymethoxy 3beta (4 iodophenyl) nortropane (123)I FP CIT) Single photon emission computed tomography (SPECT) scanning (123)I FP CIT SPECT) neurological examination, and polysomnography. RESULTS iRBD patients and PD patients with RBD had increased EMG activity compared to healthy controls. (123)I FP CIT uptake in the putamen region was highest in controls, followed by iRBD patients, and lowest in PD patients. In iRBD patients, EMG activity in the mentalis muscle was correlated to (123)I FP CIT uptake in the putamen. In PD patients, EMG activity was correlated to anti Parkinson medication. CONCLUSIONS Our results support the hypothesis that increased EMG activity during REM sleep is at least partly linked to the nigrostriatal dopamine system in iRBD, and with dopamine function in PD.
Journal of clinical sleep medicine JCSM official publication of the American Academy of Sleep Medicine