Neurologists implant neurostimulator in brain to control seizures

It has been 30 days since neurologists at the University of Alabama at Birmingham turned on the neurostimulator implanted in Sarah Conner's brain to control her seizures.

In that short time, she can already say, "I'm doing pretty good."

Conner, 24, has suffered from seizures for 10 years. In June, she became the first patient in the Southeast to receive a new device called a responsive neurostimulator since its approval by the Federal Drug Administration last year.

UAB neurosurgeon Kristen Riley, M.D., implanted the RNS system, developed by NeuroPace, into Conner's brain. It includes an electrical generator, about the size of a flash drive, which is implanted in the skull. Electrodes are run to the locations in the brain known to cause seizures.

"It is designed to record a patient's specific brain activity and recognize patterns that are associated with seizures," said Riley, associate professor in the Department of Neurosurgery. "The RNS system then delivers stimulation in order to help modulate and control the seizures."

Prior to receiving the RNS system, Conner experienced multiple semi-partial seizures every day, lasting anywhere from 10 seconds to more than a minute. When they hit, she lost all ability to function.

"It affected my motor function and sensory perception," Conner said. "I couldn't tell where my hand was, for instance. I couldn't even do simple functions such as open a door because my body wouldn't respond. It was as if I'd forgotten how to do it."

A month after the surgery, UAB neurologist Neil Billeaud, M.D., turned on the device. At a follow-up visit 30 days later, Conner reported dramatic improvement.

"I used to have several seizures every day; but now that I have the stimulator, I get a little flash, maybe once every other day," she said. "The flash lasts just a second or two and then it's gone."

The RNS system is constantly recording Conner's brain activity, and the data is downloaded to a laptop computer. If Conner says she had a flash last week, Billeaud can pinpoint the specific time and see what brain activity was occurring. As the system learns more about specific patterns that indicate a seizure is likely, Billeaud can tweak the parameters to make the RNS system even more effective in controlling seizures.

Jerzy Szaflarski, M.D., Ph.D., professor in the Department of Neurology and director of the UAB Epilepsy Center, says data from research studies dating back several years indicate that many patients will respond to the stimulation and have significant reduction in their seizures.

"This is not a treatment that will cure epilepsy," he said. "This is a treatment that will help control seizures in a very specific group of patients who otherwise are not candidates for surgery. I don't expect too many patients to become seizure-free; but if we can decrease their seizures by even half, we can make huge improvements in their lives."

Conner agrees. She is working on a degree in elementary education and had episodes in the past in which she had a seizure while student-teaching. The reduction in seizures will give her more independence.

"I'll be able to do more," Conner said. "For instance, I'll be able to drive. I'm 24, and I've never driven a car. The big hindrance with the seizures was that, when they hit, I couldn't function and was unable to do anything. Now I simply feel this flash, and then it goes away without affecting my motor function."

The RNS system is for patients who have severe seizures but do not respond to medications and are not candidates for surgery because the location of their seizure onset is at a sensitive part of the brain. It is also only for patients whose seizure onset can be traced to just one or two locations in the brain.

"We're very excited to offer this therapy to our patients who are not candidates for more traditional therapies for epilepsy," Szaflarski said. "We see multiple patients like that every year, and the RNS system could make a huge difference in the lives of those patients. There is already data to show that the quality of life of those patients has improved significantly with RNS."