Using EEG to Distinguish Epilepsy From Its Imitators

Andrew N. Wilner, MD


July 01, 2016

Andrew N. Wilner, MD: This is Dr Andrew Wilner, reporting for Medscape. I am here in Phoenix interviewing Dr Joseph Drazkowski, a professor of neurology at the Mayo Clinic. At the most recent American Academy of Neurology meeting, he was a course director and participated in another course, both of which were designed to improve the skills of neurologists with EEG and EEG video.

Joe, tell me why are you doing these courses? What's the need?

Joseph F. Drazkowski, MD: I think there's an important need for general neurologists to work through the patients who have spells of undetermined etiology. There are consequences to making the right diagnosis, and consequences to missing the diagnosis. It's very important.

The rate of proper diagnosis on this ranges from around 75% to 80%, so it's graded a C or a B, depending on how you look at it. What you really need is to get the diagnosis up a little bit higher. You need to make an accurate diagnosis for proper therapy.

Dr Wilner: Doesn't everybody just have epilepsy or...?

Dr Drazkowski: The answer is no. There's a fantastic book I would recommend from a few years ago, called Imitators of Epilepsy. Bob Fisher, one of my mentors, wrote this, and we use it to this very day. It's kind of a model for how we look at things.

There are transient neurologic events that could be all kinds of different things. We use the courses to highlight those. We take prime examples of things that we see that are a little odd, a little different, to remind people it's more than just epilepsy that we deal with.

Dr Wilner: When should a neurologist who is a treating a patient for what he or she thinks is epilepsy start thinking maybe this is one of Dr Fisher's imitators of epilepsy?

Dr Drazkowski: I think it's important if your therapy doesn't work. If your therapy is helpful and works—if, through medication trial and error, you find a particular form of whatever therapy you're going to use—that's fantastic. Use it. If it doesn't work—if you try one or two drugs, and they don't work for you—maybe a comprehensive evaluation is important.

The Institute of Medicine suggested that if you have a person with known epilepsy, you should probably get a comprehensive evaluation if the medicine's not working for you. I think that's reasonable. One, you could be missing a diagnosis. Or two, they have other options for therapy that you could be considering as well.

Dr Wilner: When you say "a comprehensive evaluation," are you talking about a referral to a comprehensive epilepsy center?

Dr Drazkowski: Yes. I think the National Association of Epilepsy Centers has done a fantastic job of categorizing and helping define what a comprehensive epilepsy center is over the past 10 years or so. The definition of what that means is important because it ensures a certain standard for the patient—that they will get a certain evaluation. It could include neuropsychological testing, proper imaging, and proper specialty testing as needed, as well as sometimes admission to the hospital with spell recording.

Dr Wilner: So spell recording would normally be EEG video?

Dr Drazkowski: EEG video with proper monitoring. Over the years, we've looked at some safety issues over time, and we monitor them pretty much out the wazoo, if you will. We do heart rate monitoring, oximetry, neuropsychological testing. They're on video 24/7. And they're followed and watched by a nurse, a tech, or a patient care tech.

Dr Wilner: I know Dr Selim Benbadis has written about this, but how often here at the Mayo Clinic would you say that someone's referred for uncontrolled seizures, and you determine that, in fact, they didn't have epilepsy at all? Do you have an idea?

Dr Drazkowski: Yeah, we do. Actually, Dr Katherine Noe, one of my colleagues who works in the center, and I looked at the statistics on that. We miss it by about 20%. Not we, specifically, but us and everybody else. Hard-to-diagnose spells are hard-to-diagnose spells. There's nothing like seeing it. There is nothing like recording it with an EEG and other physiologic parameters.

Dr Wilner: Dr Drazkowski, thank you very much for sharing your experience with the diagnosis of epilepsy.

This is Dr Andrew Wilner, reporting for Medscape.


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