Epilepsy Team Expands Use of Responsive Neurostimulation to Children Who Have Drug-Refractory Generalized Seizures

In 2019, Cincinnati Children’s was one of the first pediatric hospitals in the country to use responsive neurostimulation (RNS) off-label to treat kids with drug-refractory seizures for whom resection or ablation surgery is not a safe option. Initially, the epilepsy team used RNS on children with well-localized seizure foci. This year, we expanded our selection criteria to include some patients with generalized seizures.

RNS is a closed-loop feedback system that includes a neurostimulator generator placed inside the skull that is connected to electrodes positioned in areas of seizure focus. The U.S. Food and Drug Administration approved RNS in 2013 for adults with refractory, focal onset seizures with no more than two seizure foci.

One Patient’s Experience with RNS

One of the first patients at Cincinnati Children’s with generalized seizures to receive an RNS implant was a 15-year-old named Neave. Neave began having seizures at 16 months but was seizure-free with medication until age 8. Since then, multiple drugs and a ketogenic diet have not led to seizure freedom.

In 2020, she began vagal nerve stimulation (VNS) with limited results. By the end of 2022, Neave was experiencing one or more drop seizure clusters daily, with 30 or more seizures per cluster, some resulting in emergency medical care. She also had many absence seizures each day.

Seizures and anti-epilepsy medications have taken a toll on Neave. She struggles in school, lagging behind her peers academically and socially. “Neave’s seizures were getting worse and worse even with VNS and five medications,” says her mother, Kathleen. “She told us, ‘I will do anything to make my seizures go away.’”

The Art and Science of Adjusting Stimulation Parameters

Pediatric neurosurgeons Francesco Mangano, DO, and Jesse Skoch, MD, perform RNS surgery at Cincinnati Children’s. They connect two electrodes (with four sensors each, for a total of eight sensors) to the RNS generator. The electrodes can be implanted in different ways depending on the location of the seizure foci.

When the generator detects abnormal electrical activity in the brain, it responds within milliseconds by giving small pulses of electrical stimulation to normalize brain activity before the individual experiences seizures. Unlike other brain stimulation systems, the device records electroencephalography data that is stored in the cloud. The epilepsy team reviews the data monthly and can adjust RNS settings to personalize and optimize therapy. As in most areas of medicine, there is both an art and a science to the process.

“We have learned we have to be very dynamic when adjusting the stimulation parameters since doing so may lead to side effects for patients or reduced effectiveness,” says pediatric epileptologist Hans Greiner, MD, co-director of the Epilepsy Surgery Program. “Parents play an important role by reporting side effects they observe in their child—we receive very granular information that helps us make adjustments. We are learning together how to get optimal results with this technology.”

A Slow Start, Then Encouraging Progress

Neave’s implant surgery in February 2023 went well, but it took several months of experimental iterative titrations for RNS to take effect. Greiner continues to optimize the therapy. Meanwhile, Kathleen says Neave has significantly fewer absence seizures and can go several days without a drop seizure. Her teachers say she seems more alert and conversant and is even telling jokes.

And there’s something else that no seizure log or device can measure. “RNS has given us hope,” Kathleen says. “And for Neave and other kids with seizure disorders, hope is a powerful thing.”

(Published October 2023)

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