Assessment of Ambulatory Polygraphy in the Detection of Sleep Apnea in Multiple System Atrophy (SAMSA)

MSA patients frequently show sleep apnea. Inpatient polysomnography is currently the gold standard in the diagnosis of sleep apnea. However, its limited availability and high costs restrain a systematic screening of MSA patients. In contrast, ambulatory polygraphy is easy to achieve during a short hospitalization in a neurology unit or at the patient's home. Its validity in MSA is unknown. The purpose of this study is to assess whether ambulatory polygraphy realized during a short hospitalization in a neurology unit has the same performance than inpatient polysomnography in the diagnosis of sleep apnea in MSA patients. Polygraphy recordings will also be done during daytime to characterize diurnal respiratory disturbances. Principal Objective : To assess the performance of ambulatory polygraphy in the diagnosis of sleep apnea in MSA patients in comparison to polysomnography (reference test). Secondary Objectives : To assess the performance of ambulatory polygraphy in the diagnosis of sleep apnea in comparison to polysomnography in two subgroups of MSA patients: one at high risk and one at low risk according to the results of the Berlin Questionnaire and the Epworth Sleepiness Scale. To assess the inter-rater agreement of ambulatory polygraphy. To assess the association between sleep apnea and (i) the severity of MSA, (ii) the quality of life, (iii) the quality of sleep, and (iv) the presence of depression. To assess the association between the severity of sleep apnea and (i) the severity of MSA, (ii) the quality of life, (iii) the quality of sleep and (iv) the presence of depression. To assess diurnal respiratory disturbances in MSA by performing polygraphical recordings during daytime. To assess the association of diurnal respiratory disturbances in MSA and (i) the severity of MSA and (ii) the quality of life. Study design : Cross-sectional prospective study (delay of one month between ambulatory polygraphy during a short hospitalization in a neurology unit and inpatient polysomnography). Each test will be carried out an interpreted blind to the other test. Study plan: Visit of Selection (V0) * Verification of eligibility * Study related information Visit of inclusion (From 0 to 90 days after selection) * Verification of eligibility * Diagnosis criteria * Oral informed consent of patient or representative * Clinical examination by using UMSARS, MMSE, Berlin Questionnaire, Epworth Sleepiness Scale, PSQI, MSA-QoL, SF-36 and Beck Depression Inventory * Ambulatory polygraphy during a short hospitalization in a neurology unit Visit of follow-up (V2, 1 month ± 5 days after V1) * Clinical examination by using UMSARS, Berlin Questionnaire and Epworth Sleepiness Scale * Inpatient polysomnography Number of subjects : 30 patients (estimation of 15 patients at high risk of having sleep apnea and 15 patients at low risk).