Continuum Audio Surgical Treatments, Devices, and Nonmedical Management of Epilepsy With Dr. Daniel Friedman
Many patients with epilepsy are unable to acheive optimal seizure control with medical therapy. Palliative surgical procedures, neurostimulation devices, and other nonpharmalogical treatments can lead to a meaningful reduction in seizures and improved outcomes.
In this episode, Teshamae Monteith, MD FAAN, speaks with Daniel Friedman, MD, MSc, author of the article “Surgical Treatments, Devices, and Nonmedical Management of Epilepsy,” in the Continuum® February 2025 Epilepsy issue.
Dr. Montieth is a Continuum® Audio interviewer and an associate editor of Continuum® Audio and an associate professor of clinical neurology at the University of Miami Miller School of Medicine in Miami, Florida.
Dr. Friedman is a professor (clinical) of neurology at NYU Grossman School of Medicine and Director of NYU Langone Comprehensive Epilepsy Center at NYU Langone Health in New York, New York.
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Read the article: Surgical Treatments, Devices, and Nonmedical Management of Epilepsy
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Full episode transcript available here
Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum, the premier topic-based neurology clinical review and CME journal from the American Academy of Neurology. Thank you for joining us on Continuum Audio, which features conversations with Continuum's guest editors and authors who are the leading experts in their fields. Subscribers to the Continuum Journal can read the full article or listen to verbatim recordings of the article and have access to exclusive interviews not featured on the podcast. Please visit the link in the episode notes for more information on the article, subscribing to the journal, and how to get CME.
Dr Monteith: This is Dr Teshamae Monteith. Today, I'm interviewing Dr Daniel Friedman about his article on surgical treatments, devices, tools, and non-medication management of epilepsy, which appears in the February 2025 Continuum issue on epilepsy. Welcome to the podcast. How are you?
Dr Friedman: I'm well, how are you?
Dr Monteith: Thank you for your article.
Dr Friedman: Thank you for the opportunity to talk today.
Dr Monteith: Why don't you introduce yourself?
Dr Friedman: So yeah, so I'm Dan Friedman. I am a professor of neurology here at NYU Grossman School of Medicine and I am the director of the NYU Comprehensive Epilepsy Center. I'm primarily an adult neurologist and I treat teens and adults with hard- difficult-to-treat epilepsy, including surgical treatments for epilepsy.
Dr Monteith: And I know you see a lot of patients because I did my residency there. And so, when you graduate, you get a lot of it, like I think many, many residents. What inspired you to choose epilepsy as a profession?
Dr Friedman: I came to neurology through my interest in neuroscience. I was a neuroscience undergraduate. I was very interested in the brain and brain function. Particularly, I was interested in how neurons communicate and organize to entrain and rhythms and that encode information. And through that interest and through my experiences in the laboratory, I actually became interested in how they do that in pathological circumstances like seizures. And so, I started reading about epilepsy, and then when I started seeing patients with epilepsy, you know, I decided this is the specialty for me for a lot of reasons. One is it combines inpatient and outpatient care. You get to establish long-term relationships with patients. For many of my patients, I'm probably the doctor that they see most often. You see people across the lifespan. And what I'm going to talk about today is for some people, you actually get to cure their disease, which at the time I was coming into neurology was something pretty rare.
Dr Monteith: Yeah, that's great. Why don't you tell us, what were you thinking when you started writing the article? What did you set out to do?
Dr Friedman: What I really wanted to do is to educate neurologists out there about the options that they have for their patients with epilepsy, especially those with difficult-to-treat or drug-resistant epilepsy, and give them the tools to communicate those options. Especially for them to understand the rationale, why we choose the interventions that we do as epileptologists, how to appropriately refer patients and have them be partners in that discussion with patients and families. One of the things that we have known for a long time is that the time to referral for things like epilepsy surgery is too long. You know, the average patient with drug resistant epilepsy who undergoes epilepsy surgery waits about twenty years. And for patients who could have curative therapy, you know, become seizure free, that's a lot of life years lost. If we can get patients to that potentially life-altering therapy earlier, that'd be great.
Dr Monteith: Yeah, that is really impactful as you think about it. So why don't you tell us what the essential points of your article?
Dr Friedman: The central point of my article is really that when patients have drug-resistant epilepsy, which means that our available anti-seizure medicines are not controlling their seizures to the degree that they need, there are other treatment options. Some of those are what we call curative, which means that they could stop their seizures entirely; and some of them are palliative, they could reduce the frequency or severity of seizures and improve quality of life and other outcomes. The other thing that I wanted to highlight was, in addition to these types of therapies, there are other tools we have at our disposal that can improve the quality of life and safety of our patients with epilepsy, including devices for seizure monitoring.
Dr Monteith: And how do you define drug-resistant epilepsy? I feel like that could be a moving target.
Dr Friedman: The International League Against Epilepsy actually set out to define it about a decade ago, and they defined it as patients who fail at least two appropriately selected anti-seizure medicines due to lack of efficacy. Then they're still having ongoing seizures. What does that mean? So, that means that the medicine that was chosen was appropriate for the type of seizures that they have, whether it's focal or generalized, and that it didn't work because of a lack of efficacy and not because of side effects. And we know from multiple studies that once patients fail two medications, the likelihood that the third, fourth, fifth, etcetera, medicine will control their seizures becomes smaller and smaller. It's not impossible, but the rates fall below five percent. And so we call those patients drug-resistant.
Dr Monteith: So, it sounds like despite newer therapies, really things haven't changed in ten years.
Dr Friedman: Yeah, unfortunately, at least when the concept was first investigated back in 2000 by Quan and Brody, they found that a third of patients were drug-resistant. When they went back in the mid-2010s to relook at these patients, despite the introduction of many new medications, the rate of patients who were drug-resistant was essentially unchanged. There may be therapies that are emerging or in development that may have better odds, but right now we don't really understand what makes people drug resistant and how we can target that.
Dr Monteith: But you do raise a good point that this is about efficacy and not tolerability. And at least for some of the newer medications, they're better tolerated. If you stop the medicine because you had some side effect, that might change how that person has classified better-tolerated treatments.
Dr Friedman: It's true. And better-tolerated treatments, you can potentially use higher doses. One of the things that is not in the definition of drug-resistant epilepsy, but as a practicing neurologist, we all know, is that the patients have to take the medicine for it to be effective. And unfortunately, they have to take it every day. And if the medicine makes them feel bad, they may choose not to take it, present to you as drug-resistant, when in reality they may be drug-sensitive if you got them on medicine that doesn't make them feel bad.
Dr Monteith: So why don't we talk about patients that are ideal candidates for epilepsy surgery?
Dr Friedman: The ideal candidates for epilepsy surgery… and I'll start by talking about curative epilepsy surgery, where the goal of the surgery is to make patients seizure-free. The best candidates are patients who have lesional epilepsy, meaning that there is a visible MRI abnormality like a focal cortical dysplasia, hippocampus sclerosis, cavernoma in a part of the brain that is safe to resect, non-eloquent, and where you can safely perform a wide margin of resection around that lesion. It helps if they have few or no generalized tonic-clonic seizures and a shorter duration of epilepsy. So the ideal patient, the patient that if they came to my office, I would say you should get surgery right now, are patients with non-dominant temporal lobe epilepsy of a few years’ duration. So as soon as they've shown that they're not responding to two medicines, those are the ideal patients to say, you would have the most benefit and the least risk from epilepsy surgery.
We know from studies that patients with temporal lobe epilepsy do a little better with surgery. We know patients who have a visible lesion on MRI do better with epilepsy surgery. We know that patients who have infrequent secondarily generalized seizures do better. But all patients with drug-resistant epilepsy should be considered for some form of surgery because even if they're not candidates for a curative surgery, there may be some palliative options, whether it's surgical resections that lessen the severity of their seizures or neurostimulation devices that reduce the frequency and severity of seizures. Ideal candidates, the ones that you would push through sooner rather than later, are those who have the likelihood of the best outcomes and the least risk of neurocognitive decline.
Dr Monteith: So, you mentioned that there may be other candidates that still benefit, although maybe not ideal. You mentioned neuromodulation. What other interventions are available?
Dr Friedman: For patients who are not candidates for resective surgery, there are several neurostimulation options. There's vagus nerve stimulation, which has been around the longest. It is a device that is implanted in- under the skin near the clavicle and has a lead that goes to the left vagus nerve and delivers stimulation, electrical stimulation to the nerve. For reasons we don't fully understand, it can reduce the both the frequency and severity of seizures. Seldom does it make people seizure free, but the reduction in seizure frequency for many patients is associated with improved quality of life, reduced risk of injury, and even reduced rates of SUDEP.
We also have two intracranial neurostimulation devices we use for epilepsy. One is the responsive neurostimulator. So, this is a device that- it has leads that are implanted directly into the seizure focus and sense electrocortical brain activity and deliver electrical stimulation to attempt to abort abnormal brain activity. So functioning kind of like a cardiac defibrillator for the heart, but for seizures in the brain. And because these devices have two leads, they can be used to treat people with more than one seizure focus---so up to two---or be used in patients who are not candidates for resection because their seizure focus is in language cortex, motor cortex, things that would be unable to resect. And the RNS has somewhat better efficacy in terms of percent reduction in seizures compared to the VNS, but obviously because it's an intracranial device, it's also a little riskier. It has more potential for neurosurgical adverse effects.
There's also a deep brain stimulator for epilepsies, the same exact device that we use to treat movement disorders. We can implant in the thalamus, in either the anterior nucleus of the thalamus or now, for some patients, into the central median nucleus of the thalamus, and deliver open loop stimulation to treat epilepsy and reduce the frequency and severity of seizures as well. Unlike the RNS, you don't have to localize the seizure focus, so you don't need to know exactly where the seizures are coming from. And you could treat patients with multifocal epilepsy with seizures coming from more than two locations or even generalized seizures.
Dr Monteith: So, it sounds like there are a lot of options available to patients. I think one of the things I find challenging is when we have patients that may have some cognitive dysfunction, especially in the hospital, and they've had some seizures that are very obvious, but then there are these, maybe, events that you wonder are seizures. So, what is the utility of some of these seizure detection devices?
Dr Friedman: The development of seizure detection devices started out primarily with the observation that a majority of cases of sudden unexpected death and epilepsy, or SUDEP, occurred following tonic-clonic seizures. And there was a need to be able to monitor for convulsive seizures, especially that occur at night when people were otherwise unattended. And so, the first generation of devices that were developed came on the market, essentially detected convulsive seizures, and they alerted caregivers nearby who are able to come to the bedside, provide basic seizure first aid, turn people on the side. And theoretically all this---this hasn't been shown in studies---prevents SUDEP. And so, the ones that are currently available on the market are focused on the detection of convulsive seizures, mostly generalized tonic-clonic seizures, but some devices can also detect other seizures with very prominent motor components.
What we don't have yet available to us, and what people are working on, are devices that detect nonconvulsive seizures. We know that patients who have focal impaired aware seizures are often amnestic for their seizures. They don't know they had a seizure if family members aren't there to observe them. They may never report them, which makes treating these patients very difficult. How do you quantify disease burden in your headache patients, for instance? You say, how many headache days did you have since we last met in the clinic? Your patients will be able to report on their calendar, this many days. Well, imagine if the patients had no awareness of whether or not they had a headache day. You wouldn't know if your therapy is working or not. In epilepsy, we need those types of devices which can tell us whether patients are having seizures they're unaware of, and that may be more subtle than convulsions.
Dr Monteith: Oh, that'd be great for headache, too. You just gave me an idea, but that's the next podcast. So, you mentioned SUDEP, really important. How good are surgical interventions at reducing what we would think the prevalence of SUDEP?
Dr Friedman: For me that is one of the primary motivations for epilepsy surgery in patients who are drug-resistant, because we know that if patients who are candidates for epilepsy surgery have high SUDEP rates. Estimates range from six to nine per thousand patients per year. If surgery is successful, their mortality rates go down to the general population level. It literally can be lifesaving for some patients, especially when you're talking about curative epilepsy surgery. But we also know that the biggest driver for SUDEP risk is tonic-clonic seizures and the frequency of those tonic-clonic seizures. So even our palliative interventions, which can reduce the frequency and severity of seizures, may also reduce the risk of SUDEP. So, we know in study- observational studies of patients with VNS and with RNS, for instance, the rates of SUDEP in patients treated with those devices are lower than expected for the drug-resistant epilepsy population.
Dr Monteith: Let's talk a little bit about some of these prediction models. And you have a lot of great work in your article, so I don't want to get into all the details, but how do you use that in the real world? Do you communicate that with patients? How do you approach these prediction factors?
Dr Friedman: There are two places where, I think, clinical prediction tools for epilepsy surgery have a role. One is, for me, in my clinic where I'm talking to patients about the risks and benefits for surgery, right? You want to be able to accurately communicate the likelihood that the surgery is going to give you the desired outcome. So patients and their families can make educated decisions, be weighing the risks and benefits. I think it's important to be realistic with patients because surgery, like- you know, any surgery is not without risk, both acute risks and long-term risks. You're removing part of the brain, and, you know, every part of the brain is important. That's where I use prediction tools. But I think it's also important for the general neurologist, especially trying to triage which patients you are going to be aggressive with referring to a comprehensive epilepsy center for evaluation. Where you may use your limited time and capital with patients to counsel them on surgical treatments. Where a healthcare system with limited resources prioritizes patients. So, there's a significant need for having prediction tools that only take the input that a general neurologist seeing a patient in the clinic would have at hand. You know, the history, an MRI, an interictal EEG.
Dr Monteith: I guess part of that prediction model includes adverse outcomes that you're communicating as well.
Dr Friedman: Certainly, for me, when I'm discussing surgery for the patient in front of me, I will use prediction models for adverse outcomes as well that are informed by the kind of surgery we're proposing to do, especially when talking about things like language dysfunction and memory dysfunction after surgery.
Dr Monteith: So, you mentioned a lot of great advances, and certainly since I was a resident, which wasn't that long ago. Why don't you tell me how some of these interventions have changed your clinical practice?
Dr Friedman: Thinking about epilepsy surgery, like other surgical specialties, there's been a move to more minimally invasive approaches. For instance, when I started as an epilepsy fellow fifteen years ago, sixteen years ago, most of our surgeries involve removing a large portion of the skull, putting electrodes on the brain, doing resections through big craniotomies which were uncomfortable and risky, things like that. We now do our phase two or intracranial EEG monitoring through small burr holes in the brain using robotically placed electrodes. For many of our patients, we can actually treat their epileptic focus with a laser that is targeted through a small catheter and MRI guidance. And patients are usually home in two days with, you know, a lot less discomfort.
Dr Monteith: Well, that's great. I didn't expect that one, but I do think that translates to many areas of neurology. Really just this idea of meeting their goals and personalizing their care. My last question is, what out of these advances and what you know about the future of epilepsy, what makes you the most excited and what gives you the most hope?
Dr Friedman: I think there are a lot of exciting things in epilepsy. Last count I heard, there's something like over a hundred biotech companies developing epilepsy therapies. So that gives me hope that people are still interested in meeting the unmet needs of patients with epilepsy. And some of these therapies are really novel. For instance, there's a trial of stem cell treatments for drug-resistant temporal lobe epilepsy that's ongoing now, where inhibitory interneuron progenitor cells are implanted in the brain and kind of restore the brain circuit disruptions that we see in some of these epilepsies. There are combinations of drug and device therapies or gene therapy and device therapies that are in development, which have a lot of promise, and I think we'll have much more precise and targeted therapies within the next decade.
Dr Monteith: Awesome. I really appreciate our conversation, and thank you so much for your wonderful article. I learned a lot reading it.
Dr Friedman: Thank you.
Dr Monteith: Today I've been interviewing Dr Daniel Friedman, whose article on surgical treatments, devices, tools, and non-medication management of epilepsy appears in the most recent issue of Continuum on epilepsy. Be sure to check out Continuum audio episodes from this and other issues. And thank you to our listeners for joining today.
Dr Monteith: This is Dr Teshmae Monteith, Associate Editor of Continuum Audio. If you've enjoyed this episode, you'll love the journal, which is full of in-depth and clinically relevant information important for neurology practitioners. Use this link in the episode notes to learn more and subscribe. AAN members, you can get CME for listening to this interview by completing the evaluation at continpub.com/audioCME. Thank you for listening to Continuum Audio.