This transcript has been edited for clarity.
Andrew N. Wilner, MD: Welcome to Medscape. I'm Dr Andrew Wilner, reporting virtually from the 2022 American Epilepsy Society meeting in Nashville, Tennessee.
Today, I have the pleasure of speaking with Dr Jacqueline French, professor of neurology and epileptologist at NYU Comprehensive Epilepsy Center. Welcome, Dr French.
Jacqueline French, MD: Thank you. It's a pleasure to be with you.
Wilner: Dr French, you were chosen to present at the Presidential Symposium at this meeting. Could you give us a synopsis of what you shared with the audience?
French: The symposium was based on the work of Hughlings Jackson, a neurologist who lived about 100 years ago. He really taught us about the importance of listening to the patient, what they understand about what is going on during a seizure or what we call the phenomenology of the seizure, and how important that is to the diagnosis — not only the diagnosis of whether somebody actually has epilepsy, but what type of seizure they have and what kind of epilepsy they have.
My talk was getting people to pay attention to what the person is telling you to understand better about seizure type and presence or absence of epilepsy, and how that might relate to doing a very good, high-quality clinical trial.
Wilner: For a clinical trial, you need patients who have the disease that you're studying, right? Yet, there's no specific test for epilepsy, so it's a clinical diagnosis. How do you make that clinical diagnosis?
French: I'm glad you asked that, because many people think that there is a clinical test — and actually, you and I know that there is. If you were able to capture a seizure on video EEG monitoring, that would be confirmation of a diagnosis of epilepsy. Unfortunately, I would say 90% of the people who are enrolled in clinical trials — and they are enrolled all around the world, remember — do not have that critical piece of information to make the diagnosis, so we are reliant on other pieces of information.
When that is missing, many people think that the most important thing is an abnormal EEG or an epileptiform discharge on EEG. We actually know that the sensitivity and specificity of an interictal spike is not that high. The most important thing, in many cases, is exactly what other people observe during a seizure and what the patient feels during a seizure. Those things can actually be more diagnostic than the EEG.
Let me give you an example. If you hear the mother of someone with epilepsy saying, "Well, the seizure began with the individual's head turning far to the right-hand side, it got stuck there, then there was stiffening of one hand and the individual made a guttural noise, lost posture, and fell to the ground, and then stiffened all over and started to shake," you would be pretty sure that was an epileptic seizure.
As part of my job as president of the Epilepsy Study Consortium, which is a nonprofit, we have been now asking people to provide seizure descriptions so that we can have remote adjudication of patients in trials.
We already know, in many cases, that the EEG is normal and the MRI is normal, so we're entirely relying on the description. I will just give you the description that I presented at the Presidential Symposium, which was a rushing and burning in a patient's thighs, followed by a general rushing feeling and no loss of consciousness. All seizures are this type.
Now, that certainly could be a seizure, but in the absence of any other information to support the diagnosis, we certainly cannot be sure that is a seizure. That could be many things. That is the way we differentiate. We usually try and only enroll people in trials who have, let's say, an 80% likelihood that the event or events that they are having are epileptic seizures. That's why remote adjudication by epileptologists allows us to come to that conclusion.
Wilner: I know that many physicians, including myself, are encouraging their patients to bring in cell phone videos of these events. Do you use any of that in your adjudication, or is it all a written description at this point?
French: Unfortunately, because of privacy laws, we cannot look at a video because that would provide identifying information. We don't know who that person is, and we shouldn't know who that person is. We are looking for ways to de-identify videos, but of course, it's very difficult because much of what we're looking for, for example, is expression in the face and movements of the eyes. It's hard to obscure a person's identity while leaving those elements for adjudication.
Wilner: In the old days, they would put a little black cover over the eyes in the medical textbooks. That's probably not going to fly these days.
French: It's interesting because even if you covered the eyes, somebody might be wearing a shirt that has their bowling league on it or something like that. You have to be very careful.
Wilner: I understand that you developed a guide to help ask the questions because you want to find out not only was this a seizure, an epileptic seizure, but what type? You have to know the right questions.
French: Yes. We did also find, when we were doing adjudications, that sometimes there would be a description that we were quite satisfied was an epileptic seizure. But we were not satisfied that the individual had selected the right type of seizure. For example, the investigator, whoever they were, would describe a seizure where the individual was humming and had salivation, and then they would say that this person had not lost awareness. They would identify it as a focal aware seizure. That would be an example.
This, again, comes from not asking the right questions. We will always go back to that investigator and say, don't just ask the person if they felt that they were aware through the seizure. Actually, this gets back to Hughlings Jackson because he described something called double consciousness, which I think was amazing for 100 years ago.
That double consciousness means that the individual has a consciousness throughout the seizure. They know that time is passing. They know that they are there, but they have lost the consciousness outside of themselves. They don't know what's going on around them. They can't understand, hear, or remember what's going on around them. We would call that, in today's parlance, a focal impaired awareness seizure.
Obviously, that's very important because you wouldn't want that person to drive, for example, or to put themselves in harm's way. We need to get people to consistently ask those questions. Can you hear what other people are saying during a seizure? Can you understand it? Can you remember it afterward? These are really important questions that not everybody asks.
We do have a form called the DISCOVER form. DISCOVER stands for Diagnostic Interview Conducted Outside of Video EEG Recording. By the way, it can be administered not by a physician but by a paraprofessional. It just reminds individuals who are taking the history to ask the critical questions that will allow you to identify, first, whether this is epilepsy, and second, what the seizure type might be and what you have to do about it.
Again, it has clinical implications as well as research implications. When these individuals would give us this description and say, "This person has a focal aware seizure," then I would write back and say, "Are you sure you would let this person drive if they had this kind of seizure?" They would write back saying, "Oh yes, I would let this person drive." Then I would write back and say, "But would you be in the seat next to them while they were driving?"
Wilner: Where can I get a copy to share with the residents and the nurses in my clinic?
French: You can write to the Epilepsy Study Consortium. You can find the Epilepsy Study Consortium by typing into Google "Epilepsy Study Consortium." You can find a website and you can find the contact information. If you're interested, we will send you a copy.
Wilner: Perfect. Is there anything else you would like to add about your presentation, Dr French?
French: Just one more thing, and that is that people should be careful. One of the other points that we made at the symposium was about the tonic-clonic seizure as a very important seizure that we want to identify. The tonic-clonic seizure conveys a specific risk to people because that is the seizure that most commonly precedes sudden unexplained death in epilepsy.
It increases the risk for an individual. It is the seizure type that can produce injury because people fall and hurt themselves. It's very important to know whether that seizure type is happening. Before we used the current term, which is focal to bilateral tonic-clonic if somebody has focal epilepsy, we use the term secondary generalized. That diluted the way people understand what a secondarily generalized seizure is, which can just be anything that spreads to both sides of the brain and causes bilateral motor movement.
Tonic-clonic seizure — and again, this is indicated in the DISCOVER form — includes a period of time when the body is completely stiff, followed by jerking and a complete unconscious state, often with stridorous breathing.
Those are the things that people should ask about when they're doing their clinical interview, which will allow you to know whether this was a "secondary generalized seizure" or if this was actually a tonic-clonic convulsion or tonic-clonic seizure, in which case you should try very hard to eradicate that seizure with some form of treatment.
Wilner: Dr French, I want to thank you very much for sharing your presentation from the American Epilepsy Society in Nashville, Tennessee.
French: It was my pleasure. Thank you so much.
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Cite this: Andrew N. Wilner, Jacqueline French. What Tops an EEG for Epilepsy Diagnosis? - Medscape - Feb 27, 2023.
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