A task force of the International League Against Epilepsy has proposed changes to the system for naming and classifying types of seizures (Berg et al. Epilepsia 2010, volume 51, page 676). This is a modification of a scheme first derived in 1981. Seizures are now divided into Focal seizures or Generalized seizures. Focal is a synonym for what was previously called partial seizures. A focal seizure originates in one hemisphere of the brain. Focal (partial) seizures are no longer divided as simple (no loss of consciousness) or complex (loss of consciousness), although the use of seizure descriptors is encouraged on an individual basis. A generalized seizure has apparent origin in both hemispheres of the brain. Generalized seizures are subdivided into tonic-clonic (same as the prior classification, and before that they were called grand mal), absence (same as the prior classification, and before that they were called petit mal), myoclonic (with subtypes), clonic, tonic and atonic seizures. New types that are recognized include myoclonic absence, myoclonic seizures with eyelid myoclonia and epileptic spasms, including infantile spasms. The prior term “secondarily generalized” is no longer a classifier, on grounds that determination of a focal onset often was impossible or inaccurate.

There always is some transition pain with adoption of new seizure terminology, coupled with ongoing intermixed use of all prior generation terminology by medical and lay personnel. The new terminology is an attempt to base nomenclature upon observable features of seizures, with behavior, EEG or other types of testing. Classification has to be viewed as a work in progress, to be improved as we gain greater understanding of the underlying nature of different types of seizures.