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Ask Stanford Med: Neurologist answers your questions on drug-resistant epilepsy

An estimated 3 million adults and children in the United States suffer from epilepsy or seizures, and approximately 200,000 new cases occur annually, according to statistics from the Epilepsy Foundation. A portion of these patients can control their seizures with prescription drugs, but when medication fails, repeated seizures can seriously impair their daily life.

In the Stanford Program for Intractable Epilepsy, Josef Parvizi, MD, PhD, an associate professor of neurology and neurological sciences, works with epilepsy patients who are not responding to medication to determine if they are good candidates for surgical intervention. The procedure he performs involves removing a portion of the patient’s skull to provide access to the brain’s surface near the spot thought to be responsible for initiating the seizures. Electrode leads are placed next to the brain, with each electrode separately monitoring electrical activity there, allowing the function of the brain areas being considered for removal to be mapped and ensuring the surgery will be safe.

Below are Parvizi’s responses to a selection of questions on drug-resistant epilepsy and the procedure that were submitted using the hashtag #AskSUMed and the comments section on Scope. As a reminder, his answers are meant to offer medical information, not medical advice. They’re not meant to replace the evaluation and determination of your doctor, who will address your specific medical needs and can make a diagnosis and provide appropriate care.

Lisa K. asks: A recent study showed that surgery soon after the failure of two anti-epileptic drug trials offers the best chance for patients to prevent a lifetime of disability. How soon should patients seek a surgical intervention?

Yes, a study published in the Journal of the American Medical Association by Pete Engel, MD, PhD, and colleagues suggested that epilepsy surgery should NOT be considered as the last resort for intractable epilepsy. They selected patients who had been non-responsive to two consecutive antiepileptic medications for no more than two years before the trial. Some patients were treated with surgery and some continued taking their drugs without surgery. Patients were followed up for two years. Of those who received surgery, 73 percent experienced seizure freedom. By comparison, none of the patients who continued to take medications without surgery were seizure free. Moreover, quality of life was enhanced significantly in the surgery group. They could drive and spend time socializing with friends. How soon? Well, as soon as a patient fails two appropriately chosen and tolerated anti-epilepstic drug when used for an adequate period of time (greater than six months). If a patient has seizures and imaging studies show a clear lesion in the brain, then surgery should be considered immediately.

Matt asks: I have a 7 year-old girl with severe cognitive disabilities. She follows the Atkins for seizures diet; presented at 6 months, seizes once a week, duration 10 minutes unconscious, then 10-minute ‘tremors’. Would the procedure be considered ‘too late’ to affect her future learning? Also, her doctors believe the seizure focus to lie deep in her brain (not seen on MRI) – can this area be accessed if indeed this proves to be the location?

I am sorry to hear that your daughter is having so many seizures. It is important to monitor her seizures with video-EEG to characterize the type of events that she's having. If these seizures are epileptic and focal, then yes, she should be considered for resection surgery, i.e., surgically remove the piece of the brain that is the focus of her seizures. If the seizures are multifocal, she could benefit from devices such as vagus nerve stimulator (VNS). One could also consider corpus callosotomy surgery if your daughter is having generalized seizures that cause her to fall and injure herself.

Jim Abrahams asks: I’ve read that since 1921 the ketogenic diet has improved over 50 percent of the thousands of children and adults with drug-resistant epilepsy and that as many as 20-30 percent become seizure and drug free. In addition to almost 100 years of published data, a randomized controlled study published in 2009 supported its efficacy in children. Could you comment?

A Cochrane analysis showed that the diet results in short to medium term benefits in seizure control - like the effect of any other medication. However, the long-term outcome of the diet is questionable. Many patients find the diet difficult to tolerate, and many drop-out from using this diet because of gastrointestinal side effects and dislike for the diet.

Nolan asks: I read that an experimental implantable device may benefit epilepsy patients who don’t respond to medication. What are the advantages of a surgical intervention compared to something like this type of implantable device?

Devices are only partially helpful. They reduce seizure frequency by ~35 percent (almost like a medication). Very rarely does a patient become seizure free. Removing the brain focus of seizures, on the other hand, can result in 100 percent seizure freedom.

@EpilepsyBlogger asks: Are there any new surgeries or implants being released in the future for patients who suffer with drug-resistant epilepsy?

Two new devices are waiting for approval in the U.S. One is made by NeuroPace and the other by NeuroSigma.

Previously: Ask Stanford Med: Neurologist taking questions on drug-resistant epilepsy, Positive results in deep-brain stimulation trial for epilepsy and Brain implant designed for patients with difficult-to-treat epilepsy
Photo by Hey Paul Studios

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