Periodic leg movements in REM sleep behavior disorder and related autonomic and EEG activation.
OBJECTIVE
To assess the frequency of periodic leg movements (PLM) in idiopathic REM sleep behavior disorder (RBD) and to analyze their polysomnographic characteristics and associated autonomic and cortical activation.


BACKGROUND
PLM during sleep (PLMS) and wakefulness (PLMW) are typical features of restless legs syndrome (RLS), but are also frequently observed in patients with RBD.


METHODS
Forty patients with idiopathic RBD underwent one night of polysomnographic recording to assess PLMS frequency. PLM features, PLMS-related cardiac activation during stage 2 sleep, and EEG changes were analyzed in 15 of these patients with RBD. Results were compared with similar data obtained in 15 sex- and age-matched patients with primary RLS.


RESULTS
Twenty-eight (70%) of 40 patients with RBD showed a PLMS index greater than 10. No between-group differences were found in sleep architecture or indexes of PLMW and PLMS during non-REM sleep, but a trend for a higher PLMS index during REM sleep was found in patients with RBD. PLM mean duration and interval in the two conditions were similar. A transient tachycardia followed by a bradycardia was observed in close association with every PLMS in both groups, but the amplitude of the cardiac activation was significantly reduced in patients with RBD. In addition, significantly fewer PLMS were associated with microarousal in this condition.


CONCLUSIONS
Periodic leg movements are very common in idiopathic RBD, occurring in all stages of sleep, especially during REM sleep. In idiopathic RBD, the reduction of cardiac and EEG activation associated with PLMS suggests the presence of an impaired autonomic and cortical reactivity to internal stimuli.
Fantini
M L
ML
Centre d'étude du sommeil et des rythmes biologiques, Hôpital du Sacré-Coeur de Montréal, Québec, Canada.
Michaud
M
M
Gosselin
N
N
Lavigne
G
G
Montplaisir
J
J
D000368:Aged; D001143:Arousal / Q000502:physiology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology; D004569:Electroencephalography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D017286:Polysomnography; D020187:REM Sleep Behavior Disorder / Q000503:physiopathology*; D012148:Restless Legs Syndrome / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology