The Engel Epilepsy Surgery Outcome Scale arose out of the 1992 Palm Desert Conference on Epilepsy Surgery and is widely used to classify outcome after surgical treatment for medically refractory outcome.
Class I: Free of disabling seizures
Class II: Rare disabling seizures (“almost seizure-free”)
Class III: Worthwhile improvement
Class IV: No worthwhile improvement
Annotated Outcome Scale
Class I - Free of disabling seizures (completely seizure free; non-disabling, simple partial seizures only; some disabling seizures, but free of disabling seizures for at least 2 years; generalized convulsion with antiepileptic drug withdrawal only.)
Class II - Rare disabling seizures (initially free of disabling seizures, but rare seizures now; rare disabling seizures since surgery; more than rare disabling seizures, but rare seizures for at least 2 years; nocturnal seizures only.)
Class III - Worthwhile improvement (worthwhile seizure reduction; prolonged seizure-free intervals amounting to more than half the follow-up period, but not less than 2 years.)
Class IV - No worthwhile improvement (significant seizure reduction; no appreciable change; seizures worse.)
Engel's classification into four classes is not always adequate. For example, it is obvious that there is a difference between postsurgery patients allocated to an Engel class and who had their AEDs discontinued or reduced and those belonging to the same class but who had an increased or unchanged AED intake. One approach is to adjust the Engel classes for postoperative changes in AED state 1).