The complex relationship of sleep and epilepsy is well known. Sleep has been used for many years as a powerful EEG activator. Many researchers have supported the hypothesis that there is a specific activating effect of sleep deprivation on epileptic discharges. Sleep deprivation is defined as a sleepless state of longer than 24 hours. The increased use of MEG in diagnosis could improve the procedure for evaluating patients before surgery for epilepsy, by making invasive studies less necessary.