Accuracy of family history information on epilepsy and other seizure disorders

Background: In epilepsy as in other disorders, family history information is often obtained by asking patients about the medical histories of their relatives rather than interviewing or examining the relatives directly. The accuracy of this type of information for epilepsy and other seizure disorders is unclear.

Methods: This study used data from the Genetic Epidemiology of Seizure Disorders in Rochester study, a population-based investigation including all Rochester, MN, residents born ≥1920 with incidence of unprovoked seizures from 1935 to 1994 (case probands) and control probands matched by age, gender, and prior Rochester residency period. Seizure disorders in the first-degree relatives of case and control probands were ascertained by reviewing the relatives' medical records. Case and control probands were interviewed about seizures in their first-degree relatives using a validated 9-question screening interview. Interviewers were blinded to case-control status.

Results: Sensitivity of the family history (i.e., proportion of relatives with medical record–documented seizures who screened positive in the proband interview) was 62% (32/52) for epilepsy, 50% (7/14) for isolated unprovoked seizures, and 56% (9/16) for febrile seizures. Sensitivity did not differ by case/control status of the proband. Sensitivity was much higher for probands reporting on their offspring or siblings than their parents. Among relatives with epilepsy, 90% of offspring and 80% of siblings but only 32% of parents screened positive.

Conclusions: Family histories of epilepsy are reasonably accurate for siblings and offspring, but are underreported in parents. Family histories of other seizure disorders are underreported.