Estudio sobre la Influencia de la Posición de la Señal de Referencia en un Método para detectar patrones de actividad cerebral en señales de EEG

摘要

The choice of a proper reference is very impor-tant issue in EEG studies. Any electrode on the head has its own fluctuation of potential which inflates the apparent syn-chrony and any activity at the reference electrode that is in-termittently high and low can imítate the patterns of synchro-ny. In this work two reference positions are used in order to study the reference influence for the patterns detection process. The detection and classification process is based on a multi-step procedure that includes the location of the patterns in time, spectrum and space. EEG amplitude modulation patterns were found from all subjects that could be classified with respect to stimulus combination type significantly above chance leveis. The patterns were found in the beta range (15-22 Hz band) and they occurred in three short bursts following the stimulus onset. The result showed that the patterns were non-local, occupying the entire array and no channel lies out-side the fields to be classified, but that the location of the reference has no significant effect on the multivariate classification because similar classification rates can be obtained for differ-ent references.