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Updated: Mar 26, 2026
Dynamic Digital Biomarkers of Motor and Cognitive Function in Parkinson's Disease
Published on: July 24, 2019
Does Postural Rigidity Decrease during REM Sleep without Atonia in Parkinson Disease?
Dario Arnaldi1,2, Alice Latimier3, Smaranda Leu-Semenescu1,3
1APHP- Pitié-Salpêtrière Hospital, Sleep Disorders Unit, Paris, France.
Study Objectives:
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.
Methods:
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.
Results:
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.
Conclusions:
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.
Insights
Parkinson disease (PD) rigidity persists during REM sleep in patients with REM sleep behavior disorder (RBD), unlike in idiopathic RBD. This suggests PD and RBD muscle tone coexist, impacting movement initiation.
Area of Science:
- Neurology
- Sleep Medicine
- Movement Disorders
Background:
- Rigidity is a hallmark of Parkinson disease (PD).
- REM sleep behavior disorder (RBD) involves increased muscle tone during REM sleep.
- It is unclear if PD-related rigidity is reduced during REM sleep in PD patients with RBD.
Purpose of the Study:
- To investigate if wake postural rigidity is attenuated during REM sleep without atonia in patients with PD and RBD.
Main Methods:
- Measured levator menti muscle activity during wakefulness and sleep stages in PD patients (with/without RBD), idiopathic RBD patients, and healthy controls.
- Analyzed chin muscle tone amplitude across different sleep stages.
Main Results:
- Chin muscle tone decreased from wakefulness to N2, N3, and atonic REM sleep in all groups.
- PD patients with RBD showed the highest chin muscle tone during atonic REM sleep.
- Muscle tone did not attenuate from wake to REM sleep in PD with RBD, but attenuated by 40% in idiopathic RBD.
Conclusions:
- PD-related hypertonia and RBD-related enhanced muscle tone coexist during REM sleep in PD patients with RBD.
- This combined effect impacts chin muscle tone.
- Rapid RBD movements may initiate against this rigid postural tone.
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