In the case of seizures which are difficult to diagnose, the demonstration of epilepsy-typical graphoelements in the EEG confirms the suspected presence of an epilepsy. Activation methods are employed, since epilepsy-typical potentials may be even absent in established cerebral convulsibility in the routine wake EEG. The purpose of these method is the activation of epilepsy-typical potentials in patients, whereas the activation should not be so strong that those potentials may also be activated in healthy persons - since they can be provoked by a sufficiently strong stimulation in any individual. Hyperventilation, photostimulation, sleep, sleep deprivation and, in addition, drug provocation with Bemergrid, have proved most effective in routine diagnostic procedures; the diagnostic significance of the latter is still most problematic. - The various activation methods show a variably marked effect in the different types of seizures.