Brain Mapping of Seizure Networks Gives Hope to People with Intractable Epilepsy

Uncontrollable seizures lead to intractable epilepsy diagnosis

Sometimes medications would work, but not permanently. Koellsted had become one of those people whose seizures become intractable to medication—and she turned to Stanford's Intractable Epilepsy Program for help. An impressive set of epilepsy specialists from several medical and scientific disciplines became the team that combined the most advanced forms of seizure and functional brain mapping to find the source of Koellsted's seizures with a millimeter precision. Those maps enabled the surgery that returned Koellsted to a normal life.

"Treating intractable epilepsy is like a hunt with many twists and turns," said neurologist Josef Parvizi, MD, PhD, director of the Intractable Epilepsy Program. "Each person's seizures are unique, with a unique origin and a unique seizure network that the abnormal brain waves traverse, causing each person's unique seizure behavior."

Capturing a seizure's winding track through the brain means penetrating the bone that protects the brain. Once, neurologists observed changes in blood flow through the brain that indicate seizure activity. Now, with state-of-the-art technology, they can apply the highest power of MRI, called a 7-Tesla, to look for clues, too. They can also use a video-based EEG to gauge electrical activity. The most detailed method of seizure hunting is a combination of intracranial recording of seizure activity and functional brain mapping.

Implanting electrodes for direct brain mapping of seizures

"Implanting electrodes over the surface of the brain allows us to go beyond the skull," Parvizi said, "so we can listen to what's happening from inside the brain instead of what we can hear from the outside. From the outside you can hear the explosions, but you can't hear who is whispering and who is saying what to whom." Using this functional brain mapping technique provided information crucial for identifying the source of Koellsted's seizures.

What Parvizi and the intractable epilepsy team found in Koellsted's brain made treatment an even more delicate task than usual. Her seizures came from the part of the brain that controls sensation and movement in her legs, a part of the brain difficult to see or listen to because it's where the two halves of the brain overlap. Intracranial brain mapping would have been the only way to find that spot and it was not available when Koellsted was first diagnosed. "With thick bone and such a deep source, we would have been blind to the seizure's abnormal brain waves by just listening through the skull," Parvizi said.

With the electrodes placed directly on Koellsted's brain, Parvizi could stimulate them to connect function with location. He was watching those cells near the seizure source to determine what might happen if they were inadvertently damaged. After her fourth day of testing and mapping in the hospital, Parvizi came into Koellsted's room and said, "We found it. We're going to get it."

Functional brain mapping leads to successful epilepsy treatment

Before the intractable epilepsy team proceeded, they warned Koellsted of the risk: If something went wrong with the surgery, she might lose feeling in her legs. "I didn't care," Koellsted said. "I was in agony. Even without feeling, I could learn to function again as a human being. I could be a mother to my children and a wife to my husband. And I could go back to work."

The surgery took eight hours. The degree of precision was so demanding that the neurosurgeon did not use a scalpel. Instead, she suctioned the cells, removing just those in the main hub of the seizure source. Koellsted recalled her first moment in the recovery room. "I remember waking up and someone saying, 'Can you move your foot?' I said, 'Yes,' and they said, 'Okay, you're not paralyzed.' I remember being very happy and going back to sleep."

Finding the right team to treat intractable epilepsy

"When patients with intractable epilepsy come to Stanford for treatment," Parvizi said, "what they will find is a unique team that fuses clinical care and science. We collaborate with our colleagues in multiple departments throughout Stanford Hospital & Clinics and Stanford University, including computer science, engineering, psychology, and radiology. We get together to improve our current methods or inventing entirely new ways of mapping the brain, which will at the end lead to better treatment options for our patients. On the clinical side, we also get together to discuss each and every single epilepsy surgery case. We meet on a weekly basis, and a group of 10 to 20 clinicians who aren't afraid of opposing each other, brainstorm about the best treatment options for individual patients."

Koellsted still takes a couple of medications to control her seizures, which have now stopped completely. Their absence helped her convince the California Department of Motor Vehicles to let her take a driver's test to regain her license. She passed. That particular restoration of independence was a big part of her recovery, she said. "I wanted surgery years ago, but I realized that when the time was right, I was given the right surgeon and the right doctors. I'm grateful every day for the people who made me whole again."