Abstract: A method of fitting a proposed model for electro encephalography spectra to data derived from EEG recordings, the method comprising the steps of: (a) inputting at least one spectral trace of electroencephalographic measurements; (b) inputting a series of parameters associated with the proposed model; (c) applying a non-linear fitting algorithm to the at least one spectral trace and the at least one series of parameters, wherein the non-linear fitting model preferably can include a series of constraints associated with predetermined ones of the series of parameters so as to constrain the parameters in a predetermined range.