Sequential frequency analysis: a method to quantify event related EEG changes.

A hybrid method of frequency analysis is described by means of which EEG changes related to stimulus-response tasks have been studied. Frequency analysis was carried out using a bank of 20 analog filters by means of which quantitative spectral data were obtained as a function of time. Storing, averaging and statistical analysis of these time-varying spectral data were performed, using a general purpose computer (PDP 11-20). The method proved to be useful for analysis of the non-stationary properties of EEG changes related to certain behavioural events.