The Revised Definition and Classification of Epilepsy for Neurodiagnostic Technologists

Abstract

The definition of who has epilepsy, classification of seizure types, and types of epilepsy have all recently been revised. The classical definition of epilepsy as a person having two or more unprovoked seizures more than 24 hours apart has been expanded also to include those with one seizure and a high likelihood (more than 60%) of having another. In the new definition, epilepsy is considered to be resolved when a person is seizure-free for 10 years, the terminal 5 being off seizure medicines, or when an age-dependent syndrome has been outgrown. The new seizure type classification revises the 1981 system but maintains the primary distinction of focal- versus generalized-onset seizures. Seizures also can be of unknown onset. Focal seizures may demonstrate retention or impairment of awareness, resulting in focal-aware or focal-impaired awareness seizures. Several new focal and generalized seizure types are introduced. Classification of the epilepsies is now by grouping of seizure types, etiologies, comorbidities, and epilepsy syndromes. The goal of the new terminology is greater clarity of communication and more accurate grouping of seizure types for research. Neurodiagnostic technologists can be of great help in observing clinical and electrographic features that will define the type of seizure.

Keywords: Classification; definition; epilepsy, seizure.