Short-form Article

Redefining Idiopathic Generalised Epilepsy Syndromes

The ILAE Task Force on Nosology and Definitions updates the 2017 diagnostic criteria for the four Idiopathic Generalised Epilepsies

Background

Idiopathic Generalised Epilepsies (IGEs) comprise four syndromes, namely Childhood Absence Epilepsy (CAE), Juvenile Absence Epilepsy (JAE), Juvenile Myoclonic Epilepsy (JME), and Epilepsy with Generalised Tonic-Clonic Seizures Alone (GTCA). A classification distinguishing IGEs from Genetic Generalised Epilepsies (GGEs) has been lacking so far.

What this study addresses

This position paper identifies IGEs as a distinctive subgroup, and using knowledge from recent advances in genetics, imaging, and EEG studies, it updates the diagnostic criteria for these syndromes.

Main findings

First, the International League Against Epilepsy (ILAE) Task Force provides updated diagnostic criteria for the four IGE syndromes (CAE, JAE, JME, and GTCA). Then, it delineates IGEs as a distinctive subgroup of GGEs, while recognising certain overlapping criteria. Patients who do not satisfy the diagnostic criteria for IGEs, but experience absence, myoclonic, tonic-clonic, or myoclonic-tonic-clonic seizures with a 2.5–5.5 Hz generalised spike wave, are classified as having GGE.

The paper discusses a few representative EEGs, tabulates the features commonly observed in the four IGE syndromes, and details the diagnostic criteria for all four, including their:

1. Clinical presentation,
2. EEG and imaging findings,
3. Epidemiology, and finally,
4. Guidelines for diagnosis in regions with limited resources.

Key takeaway

Identification of IGEs as a distinctive subgroup of GGEs could improve diagnosis, prevent unnecessary investigations, optimise treatment, provide prognostic guidance, and facilitate clinical trials.