High-speed automatic analysis of eeg spike and wave activity using an analogue detection and microcomputer plotting system.

Spike and wave activity is detected by analogue circuitry which separately filters the spike and the slow wave components from the EEG. The filter outputs are converted to DC voltages, which are then compared with individually adjusted threshold voltages. A detector output pulse is produced when both the spike and the wave threshold levels are exceeded. A graph of the incidence of spike and wave activity per 15 min intervals over 24 h is plotted by a microcomputer and modified impact printer. The analysis is carried out at 60 times real time on EEG recordings obtained from unrestrained patients using a portable cassette-tape recorder.