The new ILAE report on terminology and concepts for organization of epileptic seizures: A clinician’s critical view and contribution

Abstract

The International League Against Epilepsy (ILAE) standardized classification and terminology for "epileptic seizures" of 1981 and "epilepsies and epileptic syndromes" of 1989 provide a fundamental framework for organizing and differentiating the epilepsies. However, a revision of these classifications is mandated by recent major technologic and scientific advances. Since 1997, the relevant ILAE Commissions have made significant efforts to achieve better and internationally uniform classifications as reflected in their reports of 2001, 2006, and 2010. Their initial aim to construct a "new scientific classification from application of methods used in biology that determines separate species and natural classes" proved elusive and, therefore, the last Commission in their report of 2010 confined their revisions to "new terminology and concepts" instead of "proposing a new classification (in the sense of organization) of epilepsies." It is unfortunate that most of the proposals in this report are modified interpretations and nomenclature of previous ILAE classifications; new terms are not better than the old ones, and recent advances have not been incorporated. Hence, the new ILAE report met with considerable protest from several expert epileptologists. This critical review refers mainly to the epileptic seizures, the classification of which may be an easier and less controversial task in the ILAE revisions. A revised classification should incorporate advanced knowledge of seizure pathophysiology, and clinical, interictal, and ictal manifestations. Such an attempt was made and detailed in the 2006 report of the ILAE Classification Core Group. However, these changes were largely discarded in the new ILAE report of 2010, without justification. This is inexplicable considering that the scientific advances that were available to the two Commissions were the same or had improved between 2006 and 2010. Of major concern is that "No specific classification is recommended for focal seizures which should be described according to their manifestations." Such a proposition defies the essence and the principle of any classification that requires an organization and a common language for communication. Free text descriptions are fine in a manual of differential diagnosis but not as a classification system. Another striking weakness is that even the accepted types of epileptic seizure are listed by name only, without defining them. The result is avoidable confusion. Furthermore, the report fails to consider reflex epileptic seizures. Status epilepticus is the most conspicuous omission despite immense advances of our understanding of it and its relevance on the classification. It appears that the new ILAE report does not fulfill its intent to improve the previous classifications and it may be premature to submit anything similar to this for approval by the ILAE General Assembly. The ILAE Commission could benefit by asking experts in basic and clinical science to provide a concise statement in their field of expertise as, for example, what are focal, myoclonic, or absence seizures, and their subtypes, their manifestations, and their possible pathophysiology. Areas of certainties and uncertainties, agreements and disagreements should be identified and stated clearly, with documentation of the reasons for it. Probably this is the only way forward for a truly scientific, sound, and clinically meaningful organizational system for the epileptic seizures and the epilepsies.