Real-time filtering for the estimation of steady-state visual evoked brain potentials.

It is shown that EEG visual evoked potentials elicited by repetitive stimuli in the range of 2 to 20 per second can be readily estimated in real time using a simple filtering approach. This measurement takes advantage of the fact that a comb filter will pass the important Fourier harmonics of the signal to provide an estimate of the evoked activity, plus track time-variations in the signal. Results on human subjects demonstrate the effectiveness of the approach.