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.

The revised version of these manuscripts are being reviewed by the ILAE and will then be submitted for publication.

Please select a position paper below to read draft papers:

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

19 July 2021

I congratulate the authors on the large amount of work. However, I am very concerned that a Deplhi process was used as a key part of the methodology after a literature review. Delphi is a process developed for business forecasting - it is not science and should not be projected as such. It integrates opinions, not hypothesis driven facts. I do not believe it should be standard by which the ILAE moves forward. I acknowledge that classification is tough and syndromology is beset by strong opinions (including mine), but careful hypothesis driven science is the way to improve the field - opinions and Delphi just reinforce old prejudices. These papers would be better if they highlighted what is not known and what should be investigated by the next cohort of young investigators!

Sam Berkovic

15 July 2021

I agree in general with methodology used. The concept of autoinmune enecephalopaties seizures as symptomatic may merit further review.

Alejandro de Marinis

15 July 2021

The definition of "Syndrome without laboratory confirmation" really helps clinicians in the limited resource setting such as in my country (Indonesia).

Fitri Octaviana

14 July 2021

Difficult topic with overlapping etiologies or semiology but nicely and effectively done.

van Rijckevorsel Kenou

14 July 2021

I wish to congratulate the task force members on the excellent methodological approach, keeping in line with the recent changes in definition, classification, and terminology. This brings more clarity on the definition and exclusion criteria and alerts for each syndrome, which will enhance their understanding from clinicians to researchers.

Nandan Yardi

12 July 2021

Well planned.

M. A. Aleem

9 July 2021

I am glad to be able to comment in this important ILAE activity. The task force has performed a great job indeed!

May I include a few points here

1. Evolution is an important issue in early infancy and childhood epilepsy syndrome, therefore a particular period of monitoring and meticulous data record keeping and electro-clinical reviewing is essential for reaching a correct syndromic classification.
2. The method of differentiating points mandatory, Alerts and exclusionary is excellent! I hope, future epidemiological research, prognostic evaluation and management protocol will be well recorded, however, needs practical study in future following this method.
3. Template - draft, amendment and finalizing the method, using the Delphi method is unique.
4. The Delphi survey response rate is good, however, would be better if all would have been within 67-70%.

Wonderful job! I congratulate.

Selina Husna Banu

4 July 2021

With a substantial proportion of the pediatric population with epilepsy, pediatric epileptologists like us from India should have had greater representation.

Kavita Srivastava

2 July 2021

Hello,

Nice paper. I hope to have guideline or at the end of the manuscript.

Thanks,
Yahya Naji

30 June 2021

Thank you for letting me have a chance to review this extensive and well written 'opus', and I congratulate all authors.

In comparison with the former classification from 1989 on 11 pages in Epilepsia, this one is outstanding and an encyclopedia. For the general neurologist a more compact booklet should be useful.

My only real comment is that all abbreviations should be listed.

Orvar Eeg-Olofsson

22 June 2021

These five papers are remarkable and I congratulate all of the authors on the vigorous methodology and comprehensive reviews.The papers are all well written and well referenced.

I have a challenge for all working in this field. The short forms for the syndrome names are bewildering to the non-expert. While the "old names" had some problems, at least they were real words. We all have come to accept Lennox Gastaut Syndrome. LGS is unfortunate. COPE means nothing without translation. SeLFE requires a smart phone and narcissism. SeLECTS and SelFE are very similar acronyms.

It would not be an easy task to find better names and I don't have important suggestions. But if we persist in this direction our field will become totally esoteric.

Would it be possible to assemble a small group of experts and include some language scholars to come up with real, communicative words that the non-expert can relate to?

Peter Camfield

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