The awake electroencephalogram (EEG) of patient #18 is illustrated. (a) EEG before starting the ketogenic diet (KD). Note that a short sequence of posterior 5–6 Hz activity is detectable (asterisks). Then, this rhythm was interrupted by frequent high-voltage, generalized, and multifocal sharp-waves that tended to synchronize in short bursts (arrowheads), followed by a moderate reduction of the electrical amplitude. (b) Under treatment with the KD, the presence of continuous, high-amplitude, generalized sharp-waves and slow-waves starting from the frontal region is appreciable. These waves synchronized in short generalized bursts followed by mild suppression of basal activity. Note also that the physiological posterior rhythm was not present. EEG recording was made by a 12 channel system (Galileo NT Suite Software). Images are presented on longitudinal reading montages. Amplitude, 20 µV/mm.