Quelling the storms of seizures in people with epilepsy: Part 2 of a series highlighting Sutter epilepsy research
Epilepsy—a neurological disorder caused by abnormal electrical activity in the brain—impacts almost 3.4 million nationwide. Despite advances in epilepsy treatment, approximately one-third of adults with the illness experience recurrent seizures. Read more to learn how Sutter researchers are uncovering new clues about how epilepsy develops and how it can be treated more effectively.
Stimulating the brain with neuromodulation
“Neuromodulation” is a technique that stimulates the brain or spinal cord with electrical pulses or chemicals. When used to treat epilepsy, the approach may be used as an alternative to traditional epilepsy surgical approaches or to work in synergy with them.
David King-Stephens, M.D., FAAN, Director of the Sutter Pacific Epilepsy Program in San Francisco, and Peter Weber, M.D., the program’s surgical director, were instrumental in the testing and U.S. Food and Drug Administration (FDA)’s approval in 2013 of one type of neuromodulation, the Responsive Neuromodulation System® (RNS) developed by NeuroPace.
Similar to a pacemaker that monitorsand responds to heart rhythms, the RNS® System is a medical device implanted inthe skull that monitors and responds to brain activity to help preventseizures. The device is approximately the size of a stopwatch.
CPMC was the highest enrolling site in the RNS® SystemPivotal Study—a national, multicenter clinical trial of the RNS® System for thetreatment of uncontrolled seizures in adults with epilepsy.
“Many patients experience a 70-80% reduction in seizure frequency, and the severity of seizures is also significantly reduced,” says Dr. Weber, lead neurosurgeon at Sutter for the RNS® System clinical trial. He notes that the RNS® System plus medication-based treatment is usually, for these patients, superior to standard medical management alone.
Now, nine-years after completion of the pivotal study, follow-up data is still being collected and assessed. “Results show that, for many patients, the RNS® System led to substantial reductions in seizures, with additional benefits such as improved quality of life, cognition, and memory,” says Dr. Weber. The RNS® System is also now available at the Sutter Sacramento Epilepsy Center.
Targeting the epicenter of epileptic seizures
To understand the nuances of a seizure, researchers study the brain cells (neurons) that misfire and cause the underlying electrical storm. When a seizure occurs, networks of brain cells involved in the seizure begin pulsing abnormally, leading to the symptoms patients experience during a seizure.
Anti-epileptic drugs (AEDs) are designed to modify the way neurons “fire” and how they communicate with each other and the brain’s network, thereby stopping or preventing seizures. AEDs are categorized by their main mechanism of action, although many of them have several actions and others have unknown mechanisms of action. Most of these medications are anticonvulsants or sedative medications.
There is currently no FDA-approved AED that targets potassium channels that help regulate the communications between neurons involved in the cascade of synaptic events that promote seizures.
A randomized, double-blind, placebo-controlled clinical trial called Xenon 1101, sponsored by Xenon Pharmaceuticals, is underway to test a new anticonvulsant that acts on potassium voltage-gated channels.
“The potassium channel is a novel area of epilepsy study and one that offers potential to prevent seizures through agents that target it,” says Dr. Laxer, principal investigator of the trial at CPMC with co-investigator Dr. King-Stephens. “Our epilepsy program is the only center in Northern California evaluating this new anticonvulsant.”
Three hundred patients will be enrolled in the Xenon clinical trial from enrolling sites across the U.S., Canada, Spain, and the UK.
Stay tuned later this month for Part 3 of this series on Sutter epilepsy research, which will include information on laser ablation surgery.
Read Part 1, which described new ways to map and monitor brain activity in people with epilepsy.