DETECTION OF ONSET AND TERMINATION OF MUSCLE-ACTIVITY IN SURFACE ELECTROMYOGRAMS

A method of automated detection of onset and termination of rhythmic m uscle activity in electromyograms (EMGs) is presented. A threshold lev el in the EMG is computed, such that amplitudes in. the EMG signal exc eeding this level indicate muscle activity. The threshold level is det ermined using a statistical criterion based on the amplitude distribut ion of the entire EMG signal. The working of the method is illustrated with EMG signals recorded from chewing muscles. EMG signals with a go od as well as a worse signal-to-noise ratio are presented. The method can be used for any EMG signal containing cyclic bursts of activity an d thus may be applied in studies on rhythmic movements, such as chewin g, walking and breathing. An automated method of EMG burst detection h as the advantage that large amounts of EMG data can be easily and obje ctively processed.