Jonathan Nemeth, 23, endured violent seizures that twice fractured his spine and did not respond to more than a dozen medications. EEG testing showed seizures on both sides of his brain, making standard resective surgery too risky. In a clinical trial, surgeons implanted genetically modified, GABA-producing stem cells into his temporal lobe via a three-hour, robot-assisted procedure; Nemeth has been seizure-free since February. Researchers say the experimental approach shows promise but requires more study to confirm long-term safety and effectiveness.
Stem-Cell Brain Implant Stops Seizures That Twice Fractured a 23-Year-Old's Spine
A Stem Cell Implant Into His Brain Stopped SeizuresJORDAN PORTER-WOODRUFF; GETTY IMAGES
Jonathan Nemeth, 23, of Batavia, Illinois, suffered violent nighttime seizures so severe that on two occasions they fractured his spine. He tried more than a dozen anti-seizure medications without relief, could not drive, and spent most days at home with his mother — physically limited and mentally exhausted.
Electroencephalograms at the University of Chicago showed Nemeth’s seizures originated from both hemispheres of his brain, ruling out the common surgical option of removing affected tissue on a single side. "If you do it on both sides, patients lose their memory," says Peter Warnke, MD, professor of neurological surgery at UChicago Medicine.
While Nemeth was still hospitalized after his second spinal fracture, Dr. Warnke informed him about a clinical trial testing a different approach: a stem cell therapy designed to reduce the hyperactive neuronal firing that triggers seizures. Researchers genetically modify human stem cells to become GABA-producing neurons — cells that release the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), which calms overactive brain circuits.
"This is the first treatment that addresses the biology of epilepsy, the hyperactive firing neurons, and that is fascinating," Dr. Warnke says, noting the work represents decades of research and careful development.
The operation lasted about three hours. Dr. Warnke drilled two small holes in the back of Nemeth's head and, using robotic guidance, threaded two tiny tubes into precise targets in the temporal lobe to deposit a liquid suspension containing the modified stem cells.
Since the procedure, performed last February, Nemeth has been seizure-free. "I don’t have to go to sleep in fear," he says. He has increased his hours as a cashier and plans to apply for jobs beyond biking distance once he gets his driver’s license. "It didn’t just help physically, but mentally as well," he adds.
Researchers caution that the treatment is experimental and under ongoing study: long-term safety, durability of benefit, and wider applicability remain to be proven in larger trials. Still, investigators say the approach could eventually be tested for other seizure disorders and conditions linked to low GABA levels in key brain regions, such as certain chronic pain syndromes or psychiatric disorders. Separate stem-cell strategies are also being developed to increase dopamine production as a potential therapy for Parkinson’s disease.
This report appears in the November/December 2025 issue of Men’s Health and is part of a series on 10 life-saving medical breakthroughs.
