title: Does Postural Rigidity Decrease during REM Sleep without Atonia in Parkinson Disease?
abstract: Rigidity is a muscle hypertonia typical of Parkinson disease (PD), whereas rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by abnormally increased muscle tone during REM sleep (REM sleep without atonia) and enacting dream behaviors. Because movements are not bradykinetic during RBD in patients with PD, we investigated whether the background, wake postural rigidity is attenuated during REM sleep without atonia, in absence of movement.
  
  
  
  The amplitude of levator menti (postural muscle) electromyographic activity during relaxed evening wakefulness (considered as reference) and sleep (N2, N3, atonic REM sleep, and quiet REM sleep without atonia) was measured in 20 patients with PD (with and without RBD), 10 patients with idiopathic RBD patients and 10 healthy subjects.
  
  
  
  The chin tone amplitude progressively decreased from wake to N2, N3, and atonic REM sleep in the four groups, but the highest amplitude was observed in PD patients with RBD during atonic REM sleep. Furthermore, chin muscle tone amplitude did not attenuate from wake to REM sleep without atonia in patients with both PD and RBD but dramatically attenuated (by 40% on average) in patients with idiopathic RBD.
  
  
  
  The high amplitude of chin muscle tone in PD with RBD (but not in idiopathic RBD) during REM sleep with and without atonia suggests that both PD-related hypertonia and RBD-related enhanced muscle tone coexist during REM sleep, together affecting chin muscle tone. Consequently, some rapid RBD movements likely start against a rigid postural tone.
authors: APHP- Pitié-Salpêtrière Hospital, Sleep Disorders Unit, Paris, France.|Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Italy.
authors: Dario
authors: D
authors: Arnaldi
authors: Brain Research Institute- UPMC Paris 6 Univ, Inserm U 1127; CNRS UMR 7225, IHU neuroscience, Paris, France.
authors: Alice
authors: A
authors: Latimier
authors: APHP- Pitié-Salpêtrière Hospital, Sleep Disorders Unit, Paris, France.|Brain Research Institute- UPMC Paris 6 Univ, Inserm U 1127; CNRS UMR 7225, IHU neuroscience, Paris, France.
authors: Smaranda
authors: S
authors: Leu-Semenescu
authors: Institute of Bioimaging and Molecular Physiology, National Research Council, Genoa, Italy.
authors: Fabrizio
authors: F
authors: De Carli
authors: Brain Research Institute- UPMC Paris 6 Univ, Inserm U 1127; CNRS UMR 7225, IHU neuroscience, Paris, France.|APHP- Pitié-Salpêtrière Hospital, Neurology Department, Paris, France.
authors: Marie
authors: M
authors: Vidailhet
authors: APHP- Pitié-Salpêtrière Hospital, Sleep Disorders Unit, Paris, France.|Brain Research Institute- UPMC Paris 6 Univ, Inserm U 1127; CNRS UMR 7225, IHU neuroscience, Paris, France.
authors: Isabelle
authors: I
authors: Arnulf
mesh_terms: D000368:Aged; D002680:Chin; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009122:Muscle Hypertonia / Q000150:complications* / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D010300:Parkinson Disease / Q000150:complications* / Q000503:physiopathology*; D017286:Polysomnography; D011187:Posture; D012895:Sleep, REM / Q000502:physiology*
keywords: REM sleep behavior disorder; synucleinopathy