Fig. 1

Processed electroencephalography (pEEG). The main raw traces identified by pEEG are shown in Panel A: (a) small amplitude, fast frequency wave (patient awake), (b) moderate sedation, (c) large amplitude, slow frequency wave (general anesthesia), (d) slow oscillations (deep anesthesia), (e) isoelectric trace and burst suppression. The density spectral array (DSA), a colored trace obtained from EEG and transformed into decibels of bi-hemispheric activity that can change from red (highest powers) to blue (lowest powers), is shown in Panel B. The white line in the DSA represents the spectral edge frequency (SEF) (in Hertz); 95% of the power of the brain resides below that line. The purple line in the DSA in the median frequency (MF). BIS bispectral index