REM sleep behavior disorders in multiple system atrophy.

We report the results of clinical and polysomnographic investigations on 39 consecutive multiple system atrophy (MSA) patients. Twenty-seven patients (69%) reported nocturnal motor paroxysmal episodes related to dreams, suggesting the clinical diagnosis of REM sleep behavior disorder (RBD). In 12 of them (44%), RBD preceded the clinical onset of the disease by more than 1 year. In seven (26%), the RBD onset was concomitant with and in eight (30%) was at least 2 years after the appearance of motor or autonomic symptoms. On polysomnographic recordings, 35 of 39 MSA patients (90%) had RBD. Other polysomnographic findings included nonclinical obstructive sleep apnea in 6 patients, laryngeal stridor in 8 patients, and periodic limb movements during sleep in 10 patients. Our data show that RBD represents the most common clinical sleep manifestation and polysomnographic finding in patients with MSA. RBD can frequently herald the appearance of other MSA symptoms by years. Extended polysomnographic montages are recommended in MSA sleep studies.