1. A method for determining a generalized spectral entropy of EEG signal data obtained from a patient, said method comprising the steps of: obtaining sequential EEG signal data; obtaining portions of the EEG signal data in which the signal is stationary in nature; for a portion of the EEG signal so obtained, computing the spectral entropy of the EEG signal data using the Roberts and Rezek et al. algorithm; and transforming the spectral entropy so computed to a form in which the spectral entropy from the portions of the EEG signal data are on a comparable basis.