An EEG simulator-a means of objective clinical interpretation of EEG

In 1969 Zetterberg presented a method for describing the spectral properties of an EEG signal, starting from the assumption that the signal is essentially stationary during the analysis epoch. The method involves determination of the parameters for a model consisting of a lenear filter with the ability to produce a signal with the same spectral properties as the EEG signal. Zetterberg and Ahlin described in 1975 an analogue simulator based on this model theory. With this simulator it is possible to reproduce practically all types of stationary, as well as a number of non-stationary, EEG signals. We have used this simulator to demonstrate in an illustrative manner the relation between the properties of a signal in the spectral domain and in the time domain. We have also endeavoured to anser the question: if one starts from the frequency spectrum, what does the EEG signal corresponding to this spectrum look like? We also draw attention to the usefulness of the simulator in connection with training and as an instrument for testing computer and other systems of EEG analysis.