TABLE 1.

Classification system used to define outcome^*

Class	Characteristics
I	free of disabling seizures
IA	seizure free
IB	nondisabling simple partial seizures only
IC	some disabling seizures after surgery, but free of disabling seizures for <2 yrs
ID	generalized convulsions w/ AED discontinuation
II	rare disabling seizures
IIA	initially free of disabling seizures but has rare seizures now
IIB	rare disabling seizures since op
IIC	rare seizures for the last 2 yrs
IID	nocturnal seizures only
III	worthwhile improvement, defined as >50% reduction in seizures to 90% reduction in disabling seizures
IV	no worthwhile improvement

^*Classes I and II were grouped together to represent a “favorable” outcome category, and Classes III and IV as an “unfavorable” outcome category, as in previous publications.²⁰,²¹

Abbreviation: AED = antiepileptic drug.