Despite the increasing use and availability of epilepsy surgery, knowl
edge of its results is still sketchy. Although such surgery certainly
produces improvement in seizure control and in patients' psychosocial
outcomes as measured by a wide array of techniques and instruments, th
e exact nature and magnitude of those improvement is unclear. Even les
s is known about the factors that predict which individuals are most l
ikely to benefit from surgery. This article reviews the available lite
rature on changes in seizure control, psychosocial outcomes, and cogni
tive function after resective epilepsy surgery. In addition, it outlin
es deficiencies in the current approaches and discusses promising new
approaches. In conclusion, rigorous methods, including the use of clea
rly defined and meaningful outcome measures, as well as appropriate st
atistical models such as those used to study other outcomes of seizure
s or epilepsy, are needed to determine the overall success of surgery
and to identify the patients who are most and least likely to have goo
d outcomes. (C) 1994 Wiley-Liss, Inc.