classifications

Epilepsies are classified in five ways:

-By their first cause, known as etiology.
-By the observable manifestations of the seizures, known as semiology.
-By the location in the brain where the seizures originate.
-As a part of discrete, identifiable medical syndromes.
-By the event that triggers the seizures, as in primary reading epilepsy.

In 1981, the International League Against Epilepsy (ILAE) proposed a classification scheme for individual seizures that remains in common use. This classification is based on observation (clinical and EEG) rather than the underlying pathophysiology or anatomy. In 1989, the ILAE proposed a classification scheme for epilepsies and epileptic syndromes.

This can be broadly described as a two-axis scheme having the cause on one axis and the extent of localisation within the brain on the other. Since 1997, the ILAE have been working on a new scheme that has five axes: ictal phenomenon, seizure type, syndrome, etiology and impairment. The word ictal refers to a physiologic state or event such as a seizure, stroke or headache. In electroencephalography, or EEG, the recording during an actual seizure is said to be "ictal". Inter-ictal refers to the state between events.

G. Yi Hui