Author: Lauren Ingeno
Published March 6, 2024
“At UCLA Health, specialists can offer patients three kinds of neurostimulation, which send electrical signals to the brain through battery-powered, implanted devices: responsive neurostimulation (RNS), vagal nerve stimulation (VNS) and deep brain stimulation (DBS).
The devices’ electrical currents affect the excitability of brain circuits, which can reduce the frequency of seizures or, in some cases, prevent them altogether.
“Beyond the effects on quality of life, patients with drug-resistant epilepsy have a high risk of sudden unexplained death,” says Dawn Eliashiv, MD, a professor of neurology in the David Geffen School of Medicine and co-director of the UCLA Seizure Disorders Center. “All three of these neurostimulation modalities have shown effectiveness in reducing that risk.”
Three methods of therapy”
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“Vagal nerve stimulation is the oldest form of neurostimulation, with the first device implanted in the United States in 1988 and receiving FDA approval in 1997. The VNS device is implanted under the skin on the left side of the chest and connected to a wire that is wrapped around a vagus nerve in the neck. Electrical stimulation travels from the nerve to certain areas of the brain, altering neural activity.”
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“For deep brain stimulation, a surgeon implants the device under the skin in the patient’s chest or stomach, and an electrode is run into the thalamus — a critical part of the brain that has extensive connections to other neural regions and plays a role in sensation, movement and cognition.
Both VNS and DBS have their limitations, Dr. Eliashiv says. Primarily, the stimulation for both kinds of devices is delivered on a preset cycle, rather than in a response to a seizure.
Responsive neurostimulation overcomes this constraint as a unique closed-loop, brain-responsive system. Rather than sending continuous, pre-set stimulation to the brain, the device is specially programmed to detect seizures and deliver a small amount of electrical current when one is coming on.
The device also allows doctors to continuously monitor the frequency, timing and location of electrographic activity. Each patient is given a remote monitor, which they hold over their implanted device at least once per day. The patient then uploads the data stored on the monitoring wand to a secure website, where their medical care team can review brain activity and make adjustments.
“Now that we know how to program better, we are seeing patients achieve really remarkable results,” Dr. Eliashiv says. “The benefit of the therapy is that it really is personalized for each individual’s seizure fingerprint.”
Results and effectiveness
In a real-world retrospective study of 150 patients who received RNS, nearly 80 percent had their seizures cut in half after two years of use, and 1 out of 3 reported periods of no seizures for six months in a row.
Beyond the therapy’s effectiveness in reducing seizures, the RNS device is able to capture a wealth of real-time information, which is providing researchers with deeper insights into how to treat epilepsy and other neurological conditions”(Ingeno, 2024).
The reality of many patients with epilepsy is they can’t treat their seizures with medication. They have a form of epilepsy that is medication resistant. But these other methods prove to be overall helpful. By using implants and electrical signals, the seizures starting in the brain are able to subside and patients with this resistant type of epilepsy are finally experiencing relief. Could this type of device be so effective that even the patients with medication want to switch over? There are still downfalls to medication and who really wants to medication-dependent for the rest of their lives. The problems that arise with medication are concerns about costs, manufacturing differences causing relapse of controlled seizures, inability to administer the medication in time and more. If patients were able to have a one time surgery that could stop would eliminate all these concerns, would they do it?
These types of implants have been around for a bit of time, since 1988, and have made good progress. But they could still go further!
Reference
Ingeno, L. (2024, March 6). Non-invasive epilepsy therapy offers personalized treatment for each “seizure fingerprint.” UCLA Health. https://www.uclahealth.org/news/non-invasive-epilepsy-neurostimulation
