Computer detection of EMG edges for synchronization of movement-related brain potentials.

A software-oriented technique is proposed for detection of both the start and the end of interference EMG for synchronization of single-trial movement-related brain potentials before their averaging. An iterative procedure is used on the basis of comparison of the cumulative sums of the rectified EMG segments preceding and following the time point detected by an appropriately chosen threshold. The choice of the parameters for the adjustment of the technique and the final decision for/against acceptance of the detected points are done by the experimenter in dialogue regime. In practice, after the first several trials, the procedure can be automated. In this case the number of erroneous detections, rejected by the experimenter, is small. The technique, realized on MINC 23, has been in use for a long time. Its accuracy and possibility for automation make it reliable and quick enough for various tasks related to voluntary movements and the brain potentials accompanying them.