Validity of family history data on seizure disorders

Accurate family histories of seizure disorders are important for both clinical practice and genetic research. This study evaluated validity of seizure histories of parents and siblings, obtained by interviewing 1,957 adults with epilepsy (probands). Probands were asked two questions to screen for occurrence of seizures in each relative; the first asked about epilepsy specifically, the second asked about "other seizures." For each relative who screened positive for seizures, a detailed clinical description was obtained. The final diagnosis was based on a review of all assembled information. Whenever possible, the proband's mother was interviewed independently about the family history, as were eligible relatives reported to have had seizures. Sensitivity, or the proportion of affected relatives who screened positive for seizures, was higher for epilepsy than for other seizures (87% vs. 32% assuming the mother's report to be correct, and 93% vs. 18% assuming self-report to be correct). For epilepsy, estimates of risk in siblings based on the final diagnoses were similar to previously reported findings in Rochester, Minnesota. For both isolated unprovoked seizures and acute symptomatic seizures, however, risk estimates were lower than in Rochester. These findings suggest that adults with epilepsy can report reasonably accurately about epilepsy in their parents and siblings, but isolated unprovoked seizures and acute symptomatic seizures are underreported.