Proposed Classification and Definition of Epilepsy Syndromes

The Nosology and Definitions Task Force is proposing four ILAE position papers on syndrome definitions at various ages. In addition, a fifth paper is included, that outlines the Methodology for this work, but is not a position paper. These papers summarize diagnostic electroclinical criteria as well as provide information about expected results of other investigations (imaging, genetics), frequent co-morbidities and natural history.

These papers are now posted for public comment through July 15. Please select a position paper below to read and comment:

ILAE Classification & Definition of Epilepsy Syndromes in the Neonate and Infant

ILAE Classification and Definition of Epilepsy Syndromes with Onset in Childhood

ILAE Classification and Definition of Epilepsy Syndromes with Onset at a Variable Age

ILAE definition of the Idiopathic Generalized Epilepsy Syndromes

Paolo Tinuper and Elaine Wirrell
Co-Chairs, Nosology and Definitions Task Force

General comments and comments on Methodology

14 June 2021

The Job in the four groups of syndromes is very fantastic, reflecting the efficiency of the people in the task force!

The point which I want to raise is about the term 'GGE' genetic generalized epilepsy which implies an impression that it is 'inherited' although the word 'genetic' is not the synonymous of the word 'inherited'.

The term 'GGE' will add more to the stigmatization of epilepsy and would add more to the psychological implications of the patient and family It is very difficult and possibly impossible to let people around the world realize that the word 'gentic' is not necessarily meaning 'inherited'. I suggest a modest 'opinion' to summon back the old term which was used at the era of seventies; that is the 'PGE= Primary Generalized Epilepsy' to completely replace the term GGE.

So the broader group would be 'Primary Generalized Epilepsy' and the four syndromes still constituting 'IGE= idiopathic generalized epilepsy' are harbored within.

Ghaieb Aljandeel


12 June 2021

Thank you for your invitation to discuss the proposed Classification and Definition of Epilepsy Syndromes. Indeed, the classification should dependent on the basic knowledge of nature of epilepsy.

In accordance with the ILAE 2005 definition, epilepsy is “a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures and by the neurobiologic, cognitive, psychological, and social consequences of this condition”. The definition of epilepsy requires the occurrence of at least one epileptic seizure [1]. Thus, the main factor determining the development of epilepsy is the predisposition for seizures. Hence, there is a potential for epilepsy development in cases of a genetic predisposition for disease. And vice versa, there is no epilepsy without predisposition.

In the right part of the chart of ILAE (given with the link https://ibb.co/3dCMby9), the epilepsy etiology is represented, which runs counter to the epilepsy definition by ILAE itself. The factors presented as etiological with the exception of genetic one in fact should be considered only as factors provoking seizures and not causal ones (see chart).

Now, about absence seizure. Absence is presented as generalized seizure. However, in 1987 using evoked potential method we found that absence originate in the cortex of brain hemispheres and not in the midline structures [2]. This finding was further confirmed with the aid of other methods, among them multistep dipole localization. Also through thorough analysis of the routine EEG it became evident that epileptiform spike-wave discharge occurs by 100 ms earlier in the anterior frontal region than in other regions. It was also shown by Holmes et al., in 2004, with the use of 256-channel EEG [3]. We summarized key data on this matter in our poster presentation at 13th European Congress on Epileptology in Vienna [4]. Any epilepsy, including “genuine” one, has focal origin. Therefore, great Jackson JH was right saying that every epilepsy starts from a locus [5]. Thus, appropriate correction of the ILAE Classification is needed, with identifying absence seizure also as a generalized seizure with a focal onset.
(https://ibb.co/7t6cvZG - the proposed correction of classification).

References:

  1. Fisher RS, van Emde Boas W, Blume W, et al. Epileptic seizures and epilepsy: definitions proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE). Epilepsia. 2005;46(4):470-472.
  2.  Karlov VA, Ovnatov BS. Mediobasal epileptic foci and absence ictal activity on EEG. S.S. Korsakov Journal of Neurology and Psychiatry. 1987;6:805-811. [Карлов В.А., Овнатанов Б.С. Медиобазальные эпилептические очаги и абсансная активность на ЭЭГ. Журнал невропатологии и психиатрии им. С.С.Корсакова. 1987; 6: 805-811].
  3.  Holmes M.D., Brown M., Tucker D.M. Are “Generalized” Seizures Truly Generalized? Evidence of Localized Mesial Frontal and Frontopolar Discharges in Absence. Epilepsia. 2004;45:1569-1579.
  4. Karlov V.A. Classification of epilepsies and epileptic seizures. Abstract of 13th European Congress on Epileptology Vienna, Austria 26th ‐ 30th August 2018.
  5.  Jackson JH. Relation of different divisions the Central Nervous System to one another and to parts. The Neurological Society. 1987;Dec.8th.

Vladimir Karlov and Pavel Vlasov


12 June 2021

Comprehensive.

Nensi Manusheva


12 June 2021

I appreciate the effort of the Commission. With the methodology now used the traditional "definition" is extended by incorporation of complementary exams information (including not only signal and imaging but also molecular basis updated)

Antonio Martins da Silva


2 June 2021

In the methodology, the authors should better document how they collected the review references (for example, PubMed search from xxx to xxx years) and how many papers they had reviewed. The most recent edition of “Epileptic syndromes of infancy ------, Current criteria ------, Expert opination from --- were OK, but they might not be most updated knowledge or may be biased.

Hirokazu Oguni

18 May 2021

Agreed that the four syndromes (CAE, JAE, JME and GTCA) continue to be regarded as a special group under the umbrella of IGE which might be a subgroup of GGE but all idiopathic generalised epilepsies are not genetically determined and environmental.

Other acquired factors also play an important role in epileptogenesis, for example, alcohol withdral seizure or previous brain insult or neuroinfections with normal brain imaging and subsequent late onset epilepsy which are non genetic origin. Therefore IGE of environmental origin needs some clarification.

Secondly, the term GGE (genetic generalised epilepsy) bears some social stigma which many people in developing countries may not accept for routine use except when taking family history. Genetic study is not the usual diagnostic tool in developing countries.

GP Burman


5 May 2021

I think the definition of epilepsy syndrome need rearrangement as:

Characteristic cluster of clinical neurological features with specific EEG pattern,which present at certain age,supported by specific etiological finding ,carries prognostic and treatment implications and have a range of specific co-morbidity.
(Any signs and symptoms that may occur in epilepsy syndrome belong to underlying neurological pathology).

With my best wishes
Rafid Abdulkadhim Atshan Alneghimsh