This invention describes a method for determining an abnormality of metabolic function and/or a variation of metabolic function, the method including the steps of, in a processing system receiving electroencephalography (EEG) signal information (100), analyzing the signal information (110), and determining the abnormality from the analysis (120). It also describes a method for managing the variation accordingly, the method including the steps of, detecting the abnormality (400), applying patient information (410), determining appropriate dose (420), and providing the required dose (430).