isSeizureClassificationFor epilepsy International League Against Epilepsy classification seizure classification true A seizure is a transient occurrence of symptoms and/or signs due to abnormal excessive or synchronous neuronal activity in the brain. In EpilepsyDiagnosis.Org, the term 'features' will be used to describe both the symptoms and signs that occur during seizures. These features can be used to classify seizures. A seizure does not necessarily mean that a person has epilepsy, unless the criteria for diagnosis of epilepsy are met.