Prevalence, classification, and severity of epilepsy and epileptic syndromes in children

PURPOSE: To determine the point prevalence of active childhood epilepsy in a defined area and evaluate the usefulness of ILAE classification of seizures, and epilepsies/syndromes with special interest in severe epilepsies. METHODS: By using the latest ILAE International Classification of Epileptic Seizures (ICES, 1981) and Epilepsies and Epileptic Syndromes (ICE, 1989), we determined the age- and sex-specific prevalence rates of epilepsy, type of seizures, epilepsies, and recognizable epileptic syndromes, as well as the proportion of severe cases in each seizure/epilepsy/syndrome category in all children 0-15 years of age from a geographically defined area in Finland. All medical records, neurophysiological recordings and available clinical data were reviewed retrospectively. RESULTS: Point prevalence of active epilepsy on December 12, 1992 was 3.94 per 1,000. According to ICES/ICE, we were able to classify 96% of seizures and 90% of epilepsies and syndromes. Generalized seizure and epilepsy/syndrome types were more prevalent in children 0-6 years of age and partial/localization-related in children 6-15 years of age. Epilepsy was intractable in 17% of all cases and correlated significantly with symptomatic etiology and early onset of epilepsy, as well as with additional neuroimpairments. CONCLUSIONS: A considerable number of cases fell into the nonspecific categories of ICE, which limits the value of present epilepsy/syndrome classification in terms of prognosis, prediction, and indication for special investigations in individual cases. A number of intractable cases was relatively low, indicating good prognosis in many childhood epilepsies, especially when additional neuroimpairments are absent.