Perinatal factors and seizure disorders: an epidemiologic review.

In this review, we assess the following six aspects of the epidemiological literature addressing the association between perinatal factors and seizure disorders (mainly of the grand mal type): (1) study design; (2) selection of cases; (3) selection of controls; (4) definition and ascertainment method of seizures; (5) definition and ascertainment method of perinatal factors; (6) sample size and power. Needed are studies of perinatal factors in a homogeneous group of seizure patients, such as those with grand mal seizures. Because of the rarity of the seizure disorder, most follow-up studies of this subject suffer from inadequate sample size. Improvements are suggested for case-control studies, which appear, by necessity, to be the more appropriate design.