Gender and drug effects on neuroimaging in epilepsy.

Men are different from women, and patients with epilepsy are different in many aspects from healthy control subjects. Quantitative or semiquantitative analysis of neuroimaging data depends on the comparison between either a single patient against a group of healthy or unaffected controls, or comparisons between groups of patients and controls. Matching for gender is desired, but is sometimes not possible, for example, in the case of nuclear medicine with women in childbearing age usually not being recruited as healthy controls. Antiepileptic drug treatment is the other major confounder for comparisons of cognitive functioning between patients and healthy control subjects. Whether these two covariates, gender and drug effects, are of interest or nuisance variables depends on the question and design of the neuroimaging study. Wiley Periodicals, Inc.