ESPERA study: applicability of the new ILAE criteria for antiepileptic drug resistance of focal epilepsies in current clinical practice.

A European observational cross-sectional study, ESPERA, was conducted in France and Spain in 2010. A random sample of neurologists, including specialists in epilepsy, prospectively enrolled adult patients treated for focal epilepsy with at least two antiepileptic drugs (AEDs) in combination. Investigators were asked to classify AED responsiveness of each enrolled patient according to the new 2009 ILAE criteria. These classifications were then reviewed by three experts. Potential factors of misclassification were then analyzed in order to evaluate the applicability of the new ILAE criteria for antiepileptic drug resistance in current clinical practice. Because of their complexity, use of the new ILAE criteria needs to be supported by relevant information and training to be adequately applied by neurologists in everyday practice.