Sleep disorders in multiple system atrophy: a correlative video-polysomnographic study

Objective: The reciprocal relation between breathing, heart and motor system abnormalities during sleep was studied in multiple system atrophy (MSA) by means of video-polysomnographic recordings (VPSG). Patients and Methods: Nineteen consecutive MSA patients underwent VPSG with scoring for sleep, respiratory abnormalities, heart (HR) and breathing (BR) rates, and abnormal motor activities. A comparative analysis was performed versus 10 patients with obstructive sleep apnoea syndrome (OSAS). Results: All MSA patients displayed snoring, 42% stridor, and 37% OSAS. Mean sleep SaO2 was 92.7%, and lowest SaO2 86%. Patients with stridor had a significant increase in BR from Wake to NREM and REM sleep, and higher HR during sleep. Respiratory muscles and tibialis anterior EMG tonic activity was frequently found, more often in patients with stridor. All patients had REM sleep behaviour disorders (RBD) and 88% periodic limb movements during sleep (PLMS). No OSAS patient had RBD or respiratory muscles and tibialis anterior tonic activity. Conclusions: MSA patients, especially those with associated stridor, commonly display impaired breathing and abnormal control of respiratory and limb muscles during sleep. Breathing and motor abnormalities are often concomitant in the same patient, indicating a diffuse impairment of sleep homeostatic integration that should be included within the diagnostic features of MSA.