Providing an indication of a state of awareness for a patient includes arranging data of an EEG power spectrogram to provide power versus frequency in a log-log arrangement; calculating a first best-fit line for a lower frequency region of the EEG power spectrogram, using a processor; and calculating a second best-fit line for a higher frequency region of the EEG power spectrogram. Also, a display device is used to display a density spectral array of the spectrogram using a display scale that ranges between an upper limit and a lower limit, wherein the lower limit is set based on one of the first best-fit line and the second best-fit line.