Envelope analysis of electromyogram in rem sleep behavior disorder patients

Abstract

Clinical manifestations of REM Behavior Disorder (BRD) include REM sleep without atonia (RWA) characterized by maintenance of muscle tonus associated to intense and frequent phasic motor events during REM sleep episodes. The diagnosis of RBD includes the enaction of dreams, i.e. the patient displays complex vocal and motor behaviors during REM sleep thatmay reflect dream content and the polisomnographic recording of RWA. There is a growing interest in RWA, as it has been considered a prodromal manifestation of neurodegenerative alpha-synucleinopathies such as Parkinson's disease. Current clinical diagnostic procedures include the visual inspection of polysomnographic record and categorization of electromyographic (EMG) events. Automated (computer based) strategies has been proposed to assist in EMG scoring to maximize diagnostic accuracy. Here we apply envelope analysis to EMG records obtained in healthy subjects and RBD patients. Envelope analysis give qualitative information regarding the underlying mechanism of signal generation. The mathematical properties of CVE distribution may help to obtain an unbiased scoring of electromyographic (EMG) events during sleep. The numeric value acquired by CVE is a reporter of the temporal structure of recorded elements, where phasic or pulsatile events adopt high CVE values and can be unequivocally discriminated from non pulsatile intervals. The amplitude of the envelope (AE) of EMG is directly related to muscle tonus. We propose that characterization CVE and AE may help to assist in identify RWA.