Dynamic Visual Stimulation effects on Cortical Response EEG Desynchronization

Abstract

The time evolution of the event related desynchronization/synchronization index (ERD/ERS) was used for investigating the cortical activity effects of stimulating with virtual scenes. Occipital and parietal EEG leads of 29 healthy subjects were acquired during stabilometric test without and with visual stimulation (dynamic - DS; and static - SS virtual scene). Three EEG signal-processing procedures were used to analyze the ERD at the alpha peak frequency during the virtual stimulation, one of them excluding the EEG DS segment before normalization. This procedure decreased ERD index and hence 48.3 to 58.6% of subjects presenting cortical response after changing the virtual stimulation from the static to the dynamic scenes. The Wilcoxon test (α = 0.05) results indicate difference in the cortical response due to the EEG signalprocessing procedures (smaller percentage of ERD after excluding DS). These findings indicate the potentiality of the ERD/ERS assessment in studies of postural control during visual stimulation.