ILAE Updated seizure classification Part 2: Prof. Eugen Trinka

We discuss the response to the updated classification of seizures with Prof. Eugen Trinka, including why the changes were made and how the changes are being explained and socialized. 

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Nancy Volkers: So welcome to Sharp Waves. We are here with Dr. Eugen Trinka. I will let him tell us a little bit about himself, and we are talking about the feedback and consequences of the updated classification of seizures that was published in spring of 2025.

So, Dr. Trinka, it's all you.

Dr. Eugen Trinka: Yes. Hello. My name is Professor Eugen Trinka and I'm chair of the Department of Neurology, Neurocritical Care and Neuro Rehabilitation. And I'm member of [00:01:00] EpiCARE, the European Reference Network of epilepsy centers in the European Union. And I am vice president of the International League Against Epilepsy, very keen on classification, and I'm happy that you invited me, Nancy, thank you so much. 

Nancy Volkers: Thank you for joining me. Could you give us just a little bit of background on the updated classification? You know, when, why was it done, and maybe a couple of the major changes that you think are important.

Dr. Eugen Trinka: Well, I think first of all, it's important that when we talk about classification, we do not all mean the same thing. And if we ask me about history, it's very risky because I start with the ancient Greek philosophy where they had the first ideas to classify it had a meaning arranging the objects according to certain criteria. In the Renaissance Paracelsus, for instance, and we had a recent article about that, had also a classification on epilepsies, very elaborate, but the modern times of with the International League Against Epilepsy started in the 1960s with Henri [00:02:00] Gastaut in April 1964 at the Marseilles colloquia. He brought together 100, 120 experts looking at that time at EEG, video and clinical information and discussing, for two, three days, only how to name the seizures and how they are interrelated with each other. What does it mean?

That was the basic foundation. In 1964, it was revised or refined. Six years later, 1970, then it was again an updated seizure classification. A few years later in the 1980s, there was the epilepsy syndrome classification, and then there was, again, a revision about seven years later. And then it was a long time, a big discussion about that, and some cul de sac came up.

In 2017, there was an orderly approach, well, in the years before that. And they came up with, I think, a very good classification scheme with a practical definition [00:03:00] of epilepsy that all was at that time. So what was new around 2017 was that there was a pathway for classifying seizures, which was quite useful. The basis was already set in 1964. 

So why do we change eight years later? Well, because there was feedback published in the literature. Some groups were very unhappy, some translations were impossible with this terminology, and there were some new advancements in understanding how seizures are generated.

So I think it is appropriate after around eight years to make some revisions, but keeping the old concept, taking into consideration all of the comments which were published. And that was the basis for the update in the classification, which has never been done before. So I think that is a major improvement to listen to the community, to look at the applicability and to [00:04:00] be in line with the common neurological terminology and classification. 

Nancy Volkers: Excellent. Thank you. So since the most recent update in spring 2025, there have been a few publications related to it. One of them was a survey of neurologists and neurology residents, and they were asked questions about their acceptance of the updates, would they adopt the updates. And about half supported the updates, but half also felt that they were too soon and only about 30% said that the updated classification was their preferred classification. There seemed to be a preference for the 2017 classification. 

So can you just discuss the survey, and I know that the task force responded to this publication, so can we maybe talk about this just a bit? 

Dr. Eugen Trinka: Yeah, it was very interesting because the process which was followed was extremely precise for the first time following all the regulations of the ILAE and including all [00:05:00] translations, which were never before the case. So I think we have to take that into consideration. A few weeks after that, they did the survey among a network of neurologists, it was a survey more or less, “What do you think about that classification? How do you like it?”

And here, I think, is the main problem. It's not about liking a classification or liking a term or I think it's more practical to use that or that, but whether the concept behind is the right one, because the system claims to provide a general reference system in medicine and in neurology, and specifically in epilepsy for theoretically undisputable reasons.

So this must have a precedence before you know, your own thoughts and et cetera. So what we thought when we read this, we thought, first of all, it's very interesting that a few weeks, even after dissemination, random people are asked whether they like it or not, or whether they like the previous [00:06:00] one. We went into the paper and our Spanish friends, they looked at the Spanish translation. 

Major key points. “Consciousness” was kept in the Spanish translation. You see the problem in the 2017 clarification is that they used "awareness" as a surrogate, which is a very problematic thing because it's only one part of consciousness and consciousness research would definitely say, well, this is only one part of it and you need responsiveness, too. The Spanish translation of 2017 never adapted the term "awareness" because it does not exist in Spanish. And this was confirmed by the Spanish colleagues. So one the major criticisms was not evident for the Spanish colleagues. Secondly, the strategy which they used to disseminate was quite, you know, not systematic, and 120 neurologists responded within their network. And there was no exposure or training or [00:07:00] whatsoever in this group. So you got overwhelmed with this question and then the first reaction you say, well, again, “Something new. I don't like it.” More or less. I think they, they had a nice idea to do that and we are grateful. But I think it needs a little bit of better preparation before you make something like that.

It highlighted for us how important it is to disseminate the knowledge and to explain precisely what are the changes and why are the changes there. I would be happy to go into that if we have time, Nancy.

Nancy Volkers: Excellent, thanks. Yeah. So you mentioned an important point, I think, which is that the survey was given just a few weeks after the updates came out and change—no one really likes change, and change takes time. So it sounds like you weren't particularly surprised that, you know, this update, the updates were not accepted with open arms. 

Dr. Eugen Trinka: Well. The updates were taken with [00:08:00] huge open arms, depending on whom you ask We had extremely positive feedback. And also wherever we present it, people say, “Well, finally, this is a very good change,” and I can tell you what the changes are, in fact.

So first of all, there's a cat going on my table, which I have to remove here.

First of all, it was a clear simplification to the previous classification. They had 62 seizure types, and that is almost impossible for anyone to comprehend. So we made taxonomic criteria and have two plus two classes of seizures. It's focal seizure, generalized seizure. Then you have the unknown, whether it's focal or generalized. And then you have the unclassified where you simply don't know enough of the seizure type, but you have focal and generalized.

These are the classes, biological entities you would say. And we remove the "onset" because we know now that generalized seizures [00:09:00] also have an onset somewhere which is not generalized, which points to certain parts of a network, but they can be very precisely having an onset which may be consistent. And this is new knowledge, so we had to remove the onset.

Even in the old classification, it was written that well, generalized onset also starts somewhere and engages the network, but we still call it onset, which was inconsistent. So we removed it and that was agreed in the big group. 

The second point is that consciousness is a classifier, and consciousness is more than just awareness. So you have to investigate during a seizure or get all the information— whether the patient is able to react and can have a recall about the seizure, what's happening. These two components are used in general medicine, general neurology for taking history. So that was the second big change. 

And then we have the broad description of the seizure—it is, in the basic version, observable or non-observable. [00:10:00] So you saw something, you don't need any technical equipment. You see something and you describe it. And you describe it according to the terminology. Terminology is how you use words to describe something, and classification has a biological meaning. So in the previous classification, these were mixed. So we separated that and there is a big group of Hans Luders who always criticized because when you do pre-surgical evaluation, you have to describe the seizure. Then you know where it is. It has an anatomical implication. John Hughlings Jackson started with that, and we have that now included in the descriptors of the focal seizures.

So we reduced it overall from 60-something seizure types to let's say two classes and overall 20 seizure types if you have the different generalized seizure types, which have prevailed. So I think these were the major changes overall in the group. And that makes sense. It's logic and it's [00:11:00] applicable.

So there is a recent paper which is not yet published but is going to be published soon from a Romanian group. I don't know whether you know that, but that was quite interesting because there was a prospective study design about the applicability. Some people said that it will be difficult to talk about consciousness with the patient because the people think it's loss of consciousness, it's coma.

But as you know. You are. It's not an all or nothing, but it's a gradual process. When you're very sleepy as a healthy person, well, your content of consciousness is not as sharp as when you're fully awake, so you have the quantitative and the qualitative parts of consciousness. Whenever the qua uh, quantitative consciousness, the wakefulness decreases, also the content gets a little bit blurry and your memory gets blurry.

Well, driving in a car in that situation is not good because your consciousness is not fully working, and this is what [00:12:00] people understand, it's not always coma or awake, it's this gradual process, which is very often the case in seizures. So they looked at this prospectively and they analyzed close to 500 patients in a secondary center.

So this is a basic standard neurology in Romania. And they looked at these patients and whether they could take from history, from seizure description, from the description of the semiology, whether they could obtain the data. One of the points which has been very hardly discussed with, especially with the American colleagues, about the consciousness, 97% were able to assess the information on consciousness, defined by awareness and by responsiveness. So 97%, I think that is, that is wonderful. And the basic seizure descriptors were obtainable in 98% of cases, even 99% of cases. So even in [00:13:00] a system where you have only history, the patient experiencing a seizure and the doctor asking the right question, you have a more than 90% detection rate of these items.

So it's applicable in this study and 500 patients is, I think, very good. And they have been informed about the classification. So it needs training, it needs similar to the 2017. You need to practice that. You need to make courses. And you know, this is also why we have the practical paper, the practical guide with a lot of examples and video examples so that you can learn.

And of course, we have to invest efforts so that people will use it appropriately, that they are able to use the right terms in all the languages. This is why we have the official translations for that. And I think that's a step forward because the community of the presurgical centers [00:14:00] and the ones teaching neurology are now both happy.

And we have, we have sorted out the problem. We have classifiers and we have descriptors. Classifiers refer to a biological background, focal or generalized. And descriptors tell you what you see. And what you see is the same thing in high-income countries, in low-income countries, in middle-income countries, you need eyes connected with the brain and a language ability to describe what you see.

Nancy Volkers: So you mentioned the practical guide that was recently published in Epileptic Disorders, I think in October, 2025. But anyway, later in 2025. Could you describe that just a little bit?

Dr. Eugen Trinka: We have foreseen that a change of a complex system, which is very important because all people, not only epileptologists, but also neurologists should stick to it, so it had to be clear, simple, consistent with medical [00:15:00] terminology. It needs to have some examples of practical application. This is what is especially important. And that's also one of the strengths of the Anglophone philosophy to be utilitarian. They say, well, you can think about this as a nice concept, but how do you use it?

And we wanted to address this. So we asked the group that was involved in the classification to bring examples. And almost half of them or even more brought very good examples, including video, including EEG, and basically all of the main seizure classes and different seizure types in different clinical settings were addressed there.

And I think it's helpful if you study that. It's a lot of explanation and definition in this practical guide, but that tells you how to use it. And it always goes back to the simple taxonomic criteria wherever you start from. It is a teaching document and a learning document for beginners, but [00:16:00] also for advanced people.

Nancy Volkers: Excellent, thanks. So have you personally found the updates easy to integrate? What have you experienced? 

Dr. Eugen Trinka: My personal experience, you know, I'm teaching neurology at the university, teaching neurology for psychology students, and it being one of the largest hospitals where, you know, we have a lot of teaching in the curriculum.

Finally, we don't have to explain them. The word awareness – in the emergency unit, in comes a patient with impaired consciousness. And you say, “Well, I think, doctor, it was a syncope” and this was the description. Then you say, transient loss of consciousness, but when it is a seizure you say, well, it's not consciousness, it's awareness, and this is a focal aware that didn't fit. Now we are clear. Whenever you have a transient impairment of consciousness, it can be a seizure, or it can be a syncope, or it can be also [00:17:00] psychogenic, but it's always the consciousness, which is the one which you refer to—for me, much easier. Students finally can understand it, at least in the German language, Spanish and et cetera, many other languages. So that's number one. 

Number two, we do a lot of presurgical evaluation, so these silos of the 2017 clarification were not useful in describing the seizure type according to their semiology. So the whole semiological description was, you know, free text somewhere. And now we can refer precisely to, say, the focal impaired consciousness seizure starting with an epigastric aura followed by automatism and then version to the contralateral side, et cetera. So this is very clear to describe and to use.

Without doubt you can modify things, you can update things and then make it better. And in a few years from now when we have a new knowledge, we will keep the [00:18:00] framework, but we will adapt here or there. There are some seizure types where we simply do not have enough evidence to include them in the classification, but we got some feedback about. Of course in rare epilepsies. This may be included in a future classification. 

Nancy Volkers: Great. I was going to ask if you received any other feedback since the updates were published that you wanted to address or discuss? 

Dr. Eugen Trinka: Well, the thing which is, I think, important is where I go back to philosophy and concept of mind, if you have a utilitarian concept, you simply want to use it. Well then you say it's not so important how you name the things because you have to use it, but for many other people around the world. And we made presentations and discussions. Around the world. For them it's quite important. And it's also important to have a system behind that and the system, for instance, [00:19:00] in the SNOMED terminology it goes well into this because it is a systematically working thing reflecting the biology, the classification of plants, the classification of bacteria, et cetera.

This is where we want to go, because we believe that there are biological differences. The practical implications are, of course, important in treatment. You have drugs which work better in focal seizure types in the class of focal seizures, and others work better in the generalized. And then we have broad spectrum, but the efficacy is not always the same in these seizure classes.

So I think this is important and we received feedback during the discussions, during the implementation. And we have to do a lot of communication still. We have to implement it in the conferences, make the teaching courses with videos applied, which is necessary. And I [00:20:00] think that will be an improvement and the simplification easier to use than the previous one. It's especially easier to adapt to different languages and settings.

Nancy Volkers: Great. Thank you. So it sounds like there'll be some communication, some training, some socialization to get people familiar with it. 

Dr. Eugen Trinka: Yeah. 

Nancy Volkers: Any other thoughts you want to add? 

Dr. Eugen Trinka: Well, one of the thoughts which came to me during this, you see, the public exposure, the process of the league is quite complex. And you have to find agreement among these large groups. There's a Delphi, there are several rounds, and then the rounds are there, and then some people say in the group “Well, I made up my mind. I want to go back to the first round.” And then you have to say, “Well, this is the methodology and some things are a compromise.”

Of course, some things are a compromise. So we highlighted, for instance, the spasms. We really took them out because it is important to recognize the spasms [00:21:00] as a box, which can be focal or which can be generalized. If it's focal, there is an urgent need to identify the surgical remediable candidates and syndromes. If it is generalized, you have to go for medical treatment, but you don't have to lose time. You must not lose time. You have to identify this early. This is why we have specifically explained that, and that was a compromise. Of course. I think that is also one of the strengths which we have there. And the other one was, many people from the 2017 classification were on board for this one. For them it was difficult and some of them said, “Well, it's too early.” 

Well, how long do you want to wait? It is not a matter of early. Sometimes it's better earlier than later. So we got that into the discussion. A friendly disagreement turned out to be a consensus at the end, and for the public exposure we received, the vast majority were accepting. We counted that all the vast [00:22:00] majority was accepting it and appreciating it. And now I wish of course the best for the classification to last many years until we have new concepts and research findings to include something else and more.

Nancy Volkers: Excellent. Well, thank you so much for joining me. I really appreciate it. And I hope this has been enlightening for listeners to help them understand the updates. 

Dr. Eugen Trinka: Well, I hope so too. 

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​More about the updated classification of seizures, including translations and commentary, can be found on the ILAE website.