Pacesetting therapy for epilepsy at UCH

Device acts as a “pacemaker for the brain”
February 3rd, 2016

Five years ago, Jeff Loyd was standing in a bathroom in his Wheat Ridge home, getting ready for work, when he felt a strange sensation. As he looked in the mirror, his field of view narrowed – “kind of like tunnel vision,” he recalls – just before he collapsed. When he came to, his wife was pulling him out of the bathtub.

Neurosurgeon Aviva Abosch
Neurosurgeon Aviva Abosch works on implanting the NeuroPace device in Loyd’s brain.

Loyd, now 39, had suffered an epileptic seizure, something he had never before experienced. It was the first of many electrical storms that would periodically sweep through his brain and his life. He had to stop working in the print shop where he was employed. Driving became too risky; he could never be sure when another storm would strike.

“The seizures started getting closer and closer together,” Loyd said. After he was diagnosed, he tried a variety of epilepsy medications without success. “They didn’t really help,” he said. “I got headaches that made it hard to function.” The seizures seemed to get worse when he was active, adding to his frustration.

“I don’t like being on disability,” he said. “I want to use that later in my life, when I need it.”
 

Changing course

Loyd recently chose a new clinical path to fight the seizures. After a long period of extensive testing, Loyd underwent surgery at University of Colorado Hospital Dec. 23 to implant in his brain a device he hopes will tame his neural storms. The RNS (Responsive Neurostimulation) system from Mountain View, Calif.-based NeuroPace is designed to detect disruptions of the brain’s electrical activity in areas of the brain identified as seizure centers. When the signals begin to scramble, a neuro-stimulator connected to electrodes fires electrical impulses, heading off a seizure.

The University of Colorado Epilepsy Center is one of only two facilities in the state approved to implant the NeuroPace device.

NeuroPace stimulator
The NeuroPace stimulator and electrodes that attach to regions of the brain where epileptic seizures occur. Courtesy NeuroPace.

“It’s a brain pacemaker,” said Aviva Abosch, MD, PhD, the UCH neurosurgeon and director of stereotactic and epilepsy surgery who operated on Loyd. Abosch said the NeuroPace device looks at biomarkers in the brain that tell it that a seizure is about to happen and to deliver the stimulating therapy. When the brain’s activity returns to normal, the stimulation stops and resumes again only when the device detects another imminent seizure.

“It’s the first closed-loop device for treating brain conditions,” Abosch said.

The NeuroPace is designed for people like Loyd, whose seizures have not stopped despite many epilepsy medications. Cornelia Drees, MD, an assistant professor of neurology in the Epilepsy Section, said adding medications to these patients’ regimens rarely stops the seizures. In addition, the NeuroPace device regulates activity in specific areas of the brain. It is not indicated for patients whose epilepsy is generalized; those who have epilepsy that can be treated by surgical removal or laser ablation of a single brain location; or those whose condition arises from more than two discrete brain locations.

Process of elimination

Loyd reached the decision to undergo the NeuroPace procedure after rounds of testing that eventually ruled out traditional neurosurgery to remove the part of his brain that causes the seizures.

He spent several days initially in UCH’s Electrodiagnostic Monitoring Unit (EMU). Providers attached electrodes to his scalp, then observed video electroencephalogram recordings around the clock. Loyd had seizures while he was in the EMU that indicated that the disturbances originated in the left temporal lobe of his brain, Drees said.

The question then became whether the focal point was on the surface of the temporal lobe or deeper within the tissue of the brain. If the seizures originated on the surface, surgical resection would be an option, so long as language function was not involved, Drees said. His seizures seemed to start in an area responsible for hearing, which is separate from language.

But as Abosch noted, “The brain is a big place.” The scalp EEG monitoring did not produce a “smoking gun” that pinpointed the origin of the seizures, she said. The temporal lobes are also the site of language and memory; either the left or the right temporal lobe exerts control over those functions, but not both. More tests were needed to ensure that surgery did not impair those abilities in Loyd.

A lesion would have provided a clear answer and a relatively straightforward fix to the problem, but an MRI ruled that out, Drees said. Loyd then went through a Wada test, during which a catheter was threaded through his groin to the neck. An injected medication put one half of his brain to sleep. With the left side of his brain asleep, Loyd had trouble speaking and remembering items. This meant that memory and language were supported by his left temporal lobe. To spare these important functions, he would need more precise testing to find the source of his seizures. It would be necessary to dive deeper into Loyd’s brain, Drees said.

Into the deep

He agreed to intracranial monitoring, an uncomfortable procedure that involves placing a grid of electrodes on the surface of the brain, and others more deeply into the tissue. During a week of testing in the EMU, his physicians again saw that the seizures arose in the left temporal lobe. When they stimulated the electrodes, Loyd had difficulty speaking. That implied that the seizure focus and the language areas were too close together to risk surgery. Stopping the seizures could mean impairing his ability to speak and express himself.

“That’s not a fair trade-off,” Abosch said.

Loyd thus considered the NeuroPace, a solution designed to modulate the brain circuitry rather than remove a problem portion of it.

Drees emphasized that the recommendation to Loyd of intracranial monitoring came only after all the previous diagnostic steps had occurred. The decision of whether or not to proceed was always in his hands alone, but agreeing to the NeuroPace required that he follow the arduous discovery process.

“If we locate the seizures incorrectly, we can’t do this,” Drees said.

Positive signals

A month after the NeuroPace procedure, Loyd said he had been seizure-free and felt “pretty good,” even after some exertion in building a table and putting in a water heater. Every day, he plugs into a computer and uses a scanner to record and download his brain activity. Once a week, he sends the information to a server, where Drees accesses it from her computer. She looks at his brain activity patterns and for signs that might suggest the need for additional stimulation.

While the NeuroPace RNS System won U.S. Food and Drug Administration pre-market approval in 2013, patients who receive the implant also will be part of a mandated trial to assess the safety and efficacy of the device, Abosch said. As a Level 4 Epilepsy Center, UCH can provide the pre- and postoperative specialized care needed to support the NeuroPace procedure, she added. “It’s the right thing to do for selected patients, and it increases the armamentarium of treatments we can offer.”

The information from NeuroPace could produce a rich lode of information for researchers, Drees said. “We are able to see snippets of brain waves every day, over months,” she said. “It gives us a peek into brain activity over the long term.”

Loyd looks forward to resuming the life he had before epilepsy seized control. In six months, he hopes to be helping his son, who will be 16 in April, learn to drive. As for work, he’s the rare guy who relishes the thought of being able to put in 16-hour days.

“I’d like to open up my own company, making furniture,” he said. “I’ve been working with wood my whole life. When my life is going like I like it to go, I don’t stop.”

 

About the author

Tyler Smith is a freelance writer based in metro Denver.