Interobserver agreement of the old and the newly proposed ILAE epilepsy classification in children

Purpose Accurate classification of epileptic seizures, epilepsies, and epilepsy syndromes is mandatory in both clinical practice and epilepsy research. In 2010, the International League Against Epilepsy (ILAE) proposed a new classification scheme. The aim of this study is to determine whether application of this new classification for epileptic seizures and epilepsies has improved interobserver agreement compared to the classification schemes used previously. Methods Three pediatric neurologists working in different university hospitals retrospectively classified seizures and epilepsies of 80 children (165 seizures) referred to the University Center Utrecht, based on anonymized data, according to the newly proposed (2010) as well as the old (1981/1989) ILAE classification schemes. We determined interobserver agreement of the application of both ILAE classifications with kappa statistics. Key Findings Interobserver agreement of the new classification for seizures and epilepsies is comparable to that of previous classifications. There is substantial agreement on the newly introduced etiologic axis. Significance Introduction of the new epilepsy classification has not substantially improved interobserver agreement. This study shows which items cause considerable interobserver disagreement and therefore need specification.