Rectification is required to extract oscillatory envelope modulation 1 from surface electromyographic signals
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چکیده
25 Rectification of surface electromyographic (EMG) recordings prior to their correlation 26 with other signals is a widely used form of preprocessing. Recently this practice has come into 27 question, elevating the subject of EMG rectification to a topic of much debate. Proponents for 28 rectifying suggest it accentuates the EMG spike timing information; whereas opponents indicate 29 it is unnecessary and its non-linear distortion of data is potentially destructive. Here, we examine 30 the necessity of rectification on the extraction of muscle responses, but for the first time using a 31 known oscillatory input to the muscle in the form of electrical vestibular stimulation. 32 Participants were exposed to sinusoidal vestibular stimuli while surface and 33 intramuscular EMG were recorded from the left medial gastrocnemius. We compared the 34 unrectified and rectified surface EMG to single motor units to determine which method best 35 identified stimulus-EMG coherence and phase at the single motor unit level. 36 Surface EMG modulation at the stimulus frequency was obvious in the unrectified 37 surface EMG. However, this modulation was not identified by the fast Fourier transform, and 38 therefore, stimulus coherence with the unrectified EMG signal failed to capture this covariance. 39 Both the rectified surface EMG and single motor units displayed significant coherence over the 40 entire stimulus bandwidth (1-20 Hz). Furthermore, the stimulus-phase relationship for the 41 rectified EMG and motor units shared a moderate correlation (r = 0.56). These data indicate that 42 rectification of surface EMG is a necessary step to extract EMG envelope modulation due to 43 motor unit entrainment to a known stimulus. 44 45 46
منابع مشابه
Neurophysiol Christopher J . Dakin , Brian H . Dalton , Billy L . Luu and Jean - Sébastien Blouin modulation from surface electromyographic signals Rectification is required to extract oscillatory envelope
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Rectification is required to extract oscillatory envelope modulation from surface electromyographic signals.
Rectification of surface electromyographic (EMG) recordings prior to their correlation with other signals is a widely used form of preprocessing. Recently this practice has come into question, elevating the subject of EMG rectification to a topic of much debate. Proponents for rectifying suggest it accentuates the EMG spike timing information, whereas opponents indicate it is unnecessary and it...
متن کاملThe nature of periodic input to the muscles.
TO THE EDITOR: There is much interest in the synchronization of neural discharge and its potential role in information coding within the nervous system. To assess oscillatory input to the muscle by means of corticospinal (EEG–EMG) coherence and intermuscular (EMG–EMG) coherence, it is common practice to rectify electromyographic (EMG) signals, although the rationale for rectification remains in...
متن کاملRectification of the EMG signal impairs the identification of oscillatory input to the muscle.
Rectification of EMG signals is a common processing step used when performing electroencephalographic-electromyographic (EEG-EMG) coherence and EMG-EMG coherence. It is well known, however, that EMG rectification alters the power spectrum of the recorded EMG signal (interference EMG). The purpose of this study was to determine whether rectification of the EMG signal influences the capability of...
متن کاملRectification of the EMG signal impairs the identification of 4 oscillatory input to the muscle 5 6
26 Rectification of EMG signals is a common processing step used when performing EEG-EMG 27 coherence and EMG-EMG coherence. It is well known, however, that EMG rectification alters 28 the power spectrum of the recorded EMG signal (interference EMG). The purpose of this study 29 was to determine whether rectification of the EMG signal influences the capability to capture the 30 oscillatory inpu...
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