This article reviews past classification schemes, with particular attention to the 1981 International League Against Epilepsy (ILAE) Classification of Epileptic Seizures and the 1989 ILAE Classification of the Epilepsies, Epileptic Syndromes, and Related Disorders. We also discuss recent ILAE efforts to reevaluate and revise the international classifications, focusing on the following: (1) phenomenology of epileptic seizures; (2) epileptic seizure types as unique diagnostic entities; (3) epilepsy syndromes; (4) etiology; and (5) impairment. Classification approaches are currently based primarily on clinical criteria, but can be improved with input from basic research.
