Brain Mapping of Seizure Networks Gives Hope to People with Intractable Epilepsy
For nine years, Laura Koellsted tried as hard as she could to lead a normal life. It was not easy. Every day, from deep within her brain, a cluster of cells would fire all at once, out of sequence, as out of control as a fast-moving storm.
Koellsted's brain was behaving far outside its normal routine, one where nerve cells communicate in a stable stream of electricity. Those cellular misfires Koellsted experienced are seizures. Hers were so frequent, unpredictable, and debilitating—her right leg would kick out uncontrollably and she would crash to the floor— she wasn't safe doing anything. She couldn't care for her two young children. She couldn't work. She couldn't drive. Finally, to limit her falls, she stayed in bed and when she had to move around her home, she crawled instead of walking.
- Your doctor will likely ask you many questions about how your seizures begin. Make sure you ask your family or friends to describe what happens exactly when you start having seizures.
- You will likely also have a test called an electroencephalogram (EEG). This involves placing electrodes on your scalp to measure your brain's activity.
- The Stanford Comprehensive Epilepsy Program offers high resolution MRI brain scans that provide the most detailed imaging possible (with the 7-Tesla MRI) of the most subtle abnormalities in brain structure.
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.
- Surgery may be especially helpful if you have intractable focal or partial epilepsy. During the procedure, the doctor will remove the part of your brain that is starting the seizures.
- The key to epilepsy surgery is localization of the precise source of the seizure in your brain. Patients under consideration for surgery will usually undergo video-EEG monitoring as an inpatient in order to capture five or six of their typical seizures.
- Before surgery, doctors will also map the brain, using electrodes to identify brain regions involved in specific functions to make sure that surgery will not interfere with those functions.
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."
- If evidence about the origin of your seizures is overwhelming and there is no doubt that you will tolerate the epilepsy surgery, then you can proceed to surgical treatment.
- If evidence about the origin of your seizures is strong but the location of the seizures needs to be verified, you will be referred to a surgeon for inpatient intracranial video-EEG monitoring.
- If surgery to remove the epileptic tissue is not safe for you, the team may consider a device, such as a vagus nerve stimulator (VNS) or an investigational device through a clinical trial.
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."
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