The effect of Propofol induced anesthesia on human 40-Hz auditory steady state response

40-Hz auditory steady state responses (ASSR)s recorded from 12 human subjects during Propofol-induced anesthesia are studied in this paper. The 40-Hz ASSR signals are recorded in 8 channel stimulated electroencephalogram (EEG). The ASSR sweeps are extracted from 300 stimulated EEG epochs and updated every 0.5 seconds. Variations of the signal in time and frequency in 8 different channels are investigated both in constant times before and after anesthetic injection and relative to eyelash reflex disappearance in order to achieve a consistent result among all subjects. The latter demonstrates reduction in peak to peak amplitude 40 Hz and 80 Hz components of the signals after eyelash reflex disappearance in all 8 channels for all subjects.