A generally valid definition and one that is applicable to all epileptic seizure forms could be the following: Epileptic seizures are relatively brief, sudden changes in consciousness, reasoning, behaviour, memory, senses, or sensation, or the tensing of the musculature due to a temporary functional disturbance of the nerve cells in the brain in the form of increased and reciprocal build-up of electrical discharges. This definition is certainly correct but it is much too long to remember and make use of in everyday situations. For this reason, the definition of epileptic seizures can also be simplified as the expression of a temporary functional disturbance of nerve cells, whereby the effects are dependent on which function the nerve cells involved normally have.