When epilepsy medication doesn’t work
One in 26 Americans will develop epilepsy in their lifetime. Many are able to control their seizures with medications, but between 30% to 40% have drug-resistant epilepsy.
Dr. James Tao, a University of Chicago Medicine neurologist who specializes in the diagnosis and treatment of epilepsy, discusses other treatment options when medication doesn’t control seizures.
Surgery
Epilepsy surgery, performed since the 1940s, is a very reliable procedure. For a patient with focal epilepsy, where the seizures are being caused by one part of the brain, we try to remove the seizure focus. Between 60% and 70% of patients with drug-resistant epilepsy who have this surgery become seizure-free.
Open brain surgery is effective, but also carries a higher risk for complications, pain and psychological impact. Recently, minimally invasive brain surgery for epilepsy has advanced quite significantly, particularly a procedure called laser ablation. We insert a small laser fiber and burn away the seizure focus but don’t have to open up the skull.
UChicago Medicine is one of the leading centers for epilepsy laser ablation in the country. We have been performing these procedures for the last several years and have developed quite an expertise. Nowadays, 80% to 90% of the epilepsy surgery in our center is minimally invasive.
Implanted devices
The FDA has approved three neuromodulation, or neurostimulation, devices: vagal nerve stimulation (VNS), responsive neurostimulation (RNS) and deep brain stimulation (DBS).
VNS is implanted like a pacemaker under the skin near the collarbone. The wires actually do not go into the brain but are wrapped around the vagus nerve in the neck area. This device can be used for anyone who has epilepsy because it does not require a clear seizure location, and it is quite easy to implant.
RNS, however, requires knowledge of where the seizure focus is. The device is implanted on the skull, with two wires implanted inside the brain around the seizure focus. When the seizure comes, the device can detect it and send a strong electrical shock to stop the seizure. It’s probably the most effective of all three devices, although it’s a little bit more invasive.
DBS is very similar, implanted inside the brain in the thalamus, a different part of the brain. It does not require pinpointing the seizure focus, but uses the wires to stimulate different areas to control seizures.
These devices are not cures, but they improve the symptoms. In general, VNS reduces seizures by about 50%. For RNS, the expectation is around 60% to 70% seizure reduction over five years. DBS may have comparable benefit to RNS.
Cannabis
Marijuana or cannabis has been approved by the FDA for two pediatric epilepsy syndromes that carry a high risk of intellectual impairment. CBD oil has been proven to be effective for controlling seizures in these patients. We have a few adult patients in our clinic who show a benefit, too, so this is a promising drug.
Looking ahead
We have made significant advances in the last few years. The major development is obviously the marijuana or CBD oil, because it’s a completely different category of seizure medication that might be promising in combination with other medications.
Minimally invasive surgery is a paradigm shift in surgical treatment. I think this will become the first-line surgical option for people with drugresistant epilepsy. And there is a lot of potential in the neurostimulation area. We are still gaining experience in how these devices can be best used for different patients, but people really believe in the benefits.