REM sleep behavior disorder: Motor manifestations and pathophysiology

Authors

  • Isabelle Arnulf MD, PhD

    Corresponding author
    1. Sleep disorders unit, Pitié-Salpêtrière Hospital, Pierre and Marie Curie University, Inserm U975, CRICM, Paris, France
    • Unité des pathologies du sommeil, Hôpital Pitié-Salpêtrière, 47-83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France
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  • Relevant conflicts of interest/financial disclosures: Nothing to report.

  • Full financial disclosures and author roles may be found in the online version of this article.

Abstract

Patients with REM sleep behavior disorder (RBD) enact violent dreams during REM sleep in the absence of normal muscle atonia. This disorder is highly frequent in patients with synucleinopathies (60%–100% of patients) and rare in patients with other neurodegenerative disorders. The disorder is detected by interview plus video and sleep monitoring. Abnormal movements expose the patients and bed partners to a high risk of injury and sleep disruption. The disorder is usually alleviated with melatonin and clonazepam. Limb movements are mainly minor, jerky, fast, pseudohallucinatory, and repeated, with a limp wrist during apparently grasping movements, although body jerks and complex violent (fights) and nonviolent culturally acquired behaviors are also observed. Notably, parkinsonism disappears during RBD-associated complex behaviors in patients with Parkinson's disease and with multiple system atrophy, suggesting that the upper motor stream bypasses the basal ganglia during REM sleep. Longitudinal studies show that idiopathic RBD predisposes patients to later develop Parkinson's disease, dementia with Lewy bodies, and, more rarely, multiple system atrophy, with a rate of conversion of 46% within 5 years. During this time window, patients concomitantly develop nonmotor signs (decreased olfaction and color vision, orthostatic hypotension, altered visuospatial abilities, increased harm avoidance) and have abnormal test results (decreased putamen dopamine uptake, slower EEG). Patients with idiopathic RBD have higher and faster risk for conversion to Parkinson's disease and dementia with Lewy bodies if abnormalities in dopamine transporter imaging, transcranial sonography, olfaction, and color vision are found at baseline. They constitute a highly specific target for testing neuroprotective agents. © 2012 Movement Disorder Society

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