The goal of this study is to identify spatial distributions of the EEG recordings related to the anesthesia depth. Serious adverse effects may result from the inaccurate estimation of anesthesia depth during surgery.
We analyzed the spatio-temporal distribution of spectral electroencephalogram (EEG) collected from patients subjected to general anesthesia. The approach is based on the topographic mapping of spectral features of the EEG recordings, and the analysis of the positions of the maxima and minima over the anesthesia cycle.
We found different patterns depending on the analyzed feature and on the anesthesia phase. The maxima of the spectral edge frequency (SEF) feature are closer to the nasion (frontal and temporal areas) before anesthesia, shift to farther regions during the anesthetic period, and return to regions close to the nasion during the recovery period. The minima of relative power of Gamma-band present the opposite behavior, i.e., closer to the nasion during the anesthetic period, and far apart before anesthesia and during recovery).