title: Increased Motor Activity During REM Sleep Is Linked with Dopamine Function in Idiopathic REM Sleep Behavior Disorder and Parkinson Disease.
abstract: 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 α-synucleinopathies, such as Parkinson disease (PD). Follow-up studies have shown that patients with idiopathic RBD (iRBD) have an increased risk of developing an α-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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Department of Neurology, Bispebjerg Hospital, Copenhagen, Denmark.|Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Glostrup Hospital, Copenhagen, Denmark.|Center for Healthy Aging, University of Copenhagen, Denmark.
authors.forename: Marielle
authors.initials: M
authors.lastname: Zoetmulder
authors.affiliation: Department of Clinical Neurophysiology, Glostrup Hospital, Copenhagen, Denmark.
authors.forename: Miki
authors.initials: M
authors.lastname: Nikolic
authors.affiliation: Department of Neurology, Bispebjerg Hospital, Copenhagen, Denmark.
authors.forename: Heidi
authors.initials: H
authors.lastname: Biernat
authors.affiliation: Department of Neurology, Bispebjerg Hospital, Copenhagen, Denmark.
authors.forename: Lise
authors.initials: L
authors.lastname: Korbo
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Bispebjerg University Hospital, Copenhagen, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Friberg
authors.affiliation: Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Glostrup Hospital, Copenhagen, Denmark.|Center for Healthy Aging, University of Copenhagen, Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Jennum
mesh_terms: D004298:Dopamine / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010300:Parkinson Disease / Q000378:metabolism* / Q000503:physiopathology; D017286:Polysomnography; D020187:REM Sleep Behavior Disorder / Q000378:metabolism* / Q000503:physiopathology; D012895:Sleep, REM / Q000502:physiology*
chemical_list: D004298:Dopamine
keywords: EMG; Parkinson disease; SPECT; dopamine transporters; idiopathic REM sleep behavior disorder