Responsive neurostimulation (RNS) is an epilepsy treatment that doesn't require the surgical removal of brain tissue. RNS uses an implanted device to help prevent seizures before they begin, similar to how a pacemaker detects and treats abnormal heart rhythms.
Responsive Neurostimulation
With RNS, surgeons implant a small battery-powered device called a neurostimulator in the patient's skull. The neurostimulator is connected to thin wires, called leads, which the surgeon places in the area or areas of the brain where the patient's seizures originate. The neurostimulator monitors the brain's electrical activity, and when activity that could lead to a seizure is detected, it delivers a pulse of electrical stimulation through the leads. The electrical pulse may stop the seizure before it begins.
Patients treated with RNS continue to take epilepsy medication, but their seizures may be better controlled than with medication alone. Because no brain tissue is removed, RNS poses less risk to the patient than other surgical treatments. Unlike conventional epilepsy surgery, RNS is reversible and the implant can be removed at any time.
The UCSF Epilepsy Center is one of the first centers on the West Coast to offer RNS. Our program uses a device called NeuroPace, which the FDA approved in 2013 to treat medically refractory epilepsy — epilepsy that is not well controlled by medication — in certain types of patients.
In clinical trials, nearly half the NeuroPace patients saw the frequency of their seizures decrease by at least 50 percent one year after implantation. The efficacy also appears to increase over time. Three to six years after surgery, the median decrease in seizures was 60 percent or more.
Who is a candidate?
You may be a good candidate for RNS if you meet the following criteria:
- You have partial (focal) onset seizures.
- Your seizures originate in one or two areas of the brain.
- Your seizures are frequent and disabling, even after trying two or more anti-seizure medications.
RNS can be a good alternative to other surgical treatments if your seizures arise from an area of the brain that serves a critical function like speech or movement, making it difficult or impossible to surgically remove the seizure-causing tissue.
A team of neurologists, neurosurgeons and other epilepsy experts will examine your particular case to determine if you are a good candidate for RNS.
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Procedure
Before surgery, you will undergo diagnostic tests to pinpoint where seizures originate in your brain. The surgical team will use the results to determine how many leads to use and where to place them in the brain.
The implantation procedure generally takes three to four hours. The surgeon will make at least one incision in the scalp and skull to place the neurostimulator and leads. The incisions to place the leads are usually about the size of a quarter but may be larger. The neurostimulator is usually implanted on the side and toward the back of the head.
The device is turned on in the operating room and initially programmed only to record brain activity, without delivering electrical stimulation. The device will be programmed to deliver responsive stimulation in a follow-up visit to the center.
Most patients spend one night in the hospital and are discharged the following day.
Recovery
About 10 to 14 days after surgery, you will visit the Epilepsy Center to check how your incisions are healing and how many seizures have been recorded. Your doctor will then program the device to deliver stimulation when abnormal brain activity is detected. The neurostimulator will also continue to collect data on your brain activity.
Most patients don't feel the electrical pulses. If you do experience head pain or a brief tingling sensation in your scalp, please notify your doctor so the settings on the neurostimulator can be adjusted.
You will return to the Epilepsy Center four to six weeks after surgery, and every three months thereafter, to monitor how the RNS is working. It can take as long as a year to see the full effects of RNS, and the frequency of seizures appears to continue to decline over time.
You will be given a remote monitor that allows you to collect data from the neurostimulator and send it to your doctor. Your doctor will use the data to fine-tune the system's settings at future visits. The system also includes a magnet that instructs the neurostimulator to record brain activity when you swipe it over the implant site during a seizure. You can also use the magnet to temporarily stop the stimulation.
You will receive a wallet-sized medical implant identification card. Please carry this card with you at all times. You will need to show it when going through security systems at airports or elsewhere.
After the device is implanted, you must avoid certain medical treatments that could cause energy to travel through the device to the brain, leading to brain injury or death. These include MRI, diathermy, electroconvulsive therapy and transcranial magnetic stimulation.
The neurostimulator's battery generally lasts about two-and-a-half to four years. When your battery is low, you will need to have the neurostimulator surgically replaced. Unless the leads also need to be replaced, the new neurostimulator will be connected to the same leads.
For more information, please contact one of our epilepsy nurse specialists:
Neurology:
Maritza Lopez, (415) 353-2134
Neurosurgery:
Mariann Ward, (415) 353-2347
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.
Minimally invasive treatments for epilepsy
Learn more about surgical treatment options for epilepsy from Dr. Edward Chang, chair of neurological surgery at UCSF.
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