We performed standard 30-minute initial EEG recordings for all patients participating in the study to exclude any pre-existing epileptic EEG patterns. We took the initial EEG recordings in a dark quiet room for 5 minutes as a baseline, followed by three eye opening and closing sequences of 10 seconds each and photostimulation lasting 10 minutes (flash stimuli at frequencies of 3/6/9/12 Hz- alpha; 15/18/21/24 Hz- beta). Then we obtained another baseline reading and we asked the patients to achieve a state of hyperventilation by taking 20 forceful breathes per minute for five minutes. Finally, we obtained another baseline reading.