A method of extracting brain frequency sub bands corresponding to a medical condition such as Alzheimers Disease from EEG time series data of a patient includes the steps of applying wavelet transforms to the EEG time series data to generate a continuous wavelet transformation time series at each wavelet scale, calculating Wavelet Entropy (WE) and Sample Entropy (SE) directly from the Continuous Wavelet Transformation time series at each wavelet scale, calculating arithmetic or geometric means and accumulations across scale ranges of interest and selecting data from major brain frequency sub-bands as candidate sets of extraction features for analysis as a diagnostic signature for the medical condition. Diagnostic signatures for Alzheimers disease are found when values of WE or SE are in certain ranges when EEG data is collected and analyzed in connection with certain analytical tasks such as an Eyes Open task.
