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What Tests Are Needed before Epilepsy Surgery?

Learn what tests are needed before epilepsy surgery from Steve Wolf, MD and Patty McGoldrick, NP in this Howcast video.


Patty: Now when we talk about the tests that we need before epilepsy surgery, we're doing tests to make sure that we're absolutely certain which area of the brain the seizures are coming from, and exactly which procedure we want to do. We start with something called a video EEG, which means overnight, it's usually a couple of nights in the hospital. The EEG technologist places these little electrodes on your head in various spots, and what that helps us do is to localize which area of the brain the seizures are coming from. So that looks at the electricity of the brain. We also do an MRI which will show us if there are any abnormalities in the brain itself.

Male: So EEG looks at the electricity of the brain, the MRI looks at the structure of the brain, and sometimes we do a PET scan. PET scans look at the metabolism of the brain.

Patty: So PET scans will tell us even if the MRI is normal, but the EEG is pointing to a specific area, the PET scan will show where there is lower or higher metabolism in the brain and we can tell if that's an area that might be causing seizures and epilepsy.

Male: PET scans can look at cold spots, and again if there's a cold spot with abnormal metabolism that's very suggestive of a seizure zone and of course the EEG is pointing to the electricity, so if we can get these tests all to converge to one area of the brain that would help us to decide whether someone's a good surgery candidate.

Patty: Now we also do something, and we don't do it in every case, but we do something called a functional MRI where a person goes into the MRI machine, which again is looking at the structure of the brain, and while they're in the scanner they're asked to do certain tasks, maybe reading, listening, talking, moving arms and legs, and that will pin point exactly on the brain which area controls movement, controls speech, controls language and talking.

Male: So functional MRI gives us that safety test, to let you know where the important features are, like arm, leg, as Patty was saying, and so that's not helping you to diagnose the epilepsy but if you're considering surgery it helps to give that safety margin of feeling OK these guys know where my seizures come from and know what areas not to go after.

Patty: Another test that we do is called a Wada, which is more of an invasive procedure, it involves an injection of am barbital, half of the brain is put to sleep at a time, and that will help us know where language is and where memory is.

Male: So that's another safety test because if you're going to do surgery on somebody you really want to know where the dominant memory center is and where their language is. What's the goal, to do no harm and to make the patient better than before.

Patty: And that Wada test is especially needed for temporal lobe epilepsy because we want to make sure if you take out one of the temporal lobes that you're not going to cause any harm. So the tests again that we use before epilepsy surgery are both to see where the seizures are coming from and to provide a margin of safety so that we're not taking out anything that's necessary and important. So we do MRI, video EEG, functional MRI, PET scan, and Wada.

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