A real-time software system on the PDP-11 for two-channel EEG spectral analysis during surgery

Three functions are performed in real time by a stand-alone PDP-11-assembly language program. First two channels of EEG data are acquired by quantization techniques; second spectral analysis of the EEG data is carried out; third the resulting spectra are displayed as time compressed spectral profiles on an X-Y plotter. The method provides EEG time trends during anesthesia, permitting evaluation of brain functions.