Responsive neurostimulation system

The responsive neurostimulation (RNS)® system is an implantable device used to treat seizures and monitor for abnormal brain activity. The RNS device is similar to a pacemaker for the heart. It is approved for adults with focal seizures that are not controlled by anti-seizure medication.

RNS is a comprehensive system that continuously monitors brain activity, detects seizure activity as it starts, and delivers an electrical pulse designed to stop a seizure.

The responsive neurostimulation system has several parts:

• A battery-operated RNS neurostimulator device
• Small wires (leads) that deliver electrical current to the brain
• A magnet
• A patient remote monitor
• A programming device

Your doctor programs the device specifically for you based on your history and seizure patterns to detect abnormal brain activity that may cause a seizure.

The leads send constant information about brain activity to the neurostimulator device. If the device detects abnormal activity, it quickly delivers small electrical impulses through the leads. These impulses interrupt the abnormal electrical activity to stop or prevent seizures just as they begin.

Before RNS surgery, you will have brain imaging and other diagnostic testing to pinpoint the areas of the brain where your seizures begin. The RNS leads will be placed in these areas.

Surgery to place the RNS device is an inpatient procedure that takes about four hours. General anesthesia puts you to sleep to keep you comfortable.

During the RNS procedure, your doctor:

1. Makes an incision in the scalp.
2. Makes tiny holes in the skull.
3. Places the leads into areas of the brain where seizures begin. At Penn Medicine, we use robotic guidance systems to ensure precise and safe placement of the leads. These leads may be placed on top of the brain or within the brain itself.
4. Implants a holder for the neurostimulator device. The neurostimulator fits snugly inside of the holder.
5. Connects the lead wires to the RNS device and tests them to make sure they work properly.
6. Closes the incisions.

Most people stay in the hospital for one to two days after RNS. Many people resume their daily routines within a few days after returning home. Most people return to work within two to four weeks.

You have regular appointments with your neurologist to fine-tune the programming of the RNS device. Your neurologist may also adjust your anti-seizure medications over time.

Many people who have RNS find that they need lower doses of anti-seizure medication after surgery.

The RNS device battery should last about eight to 10 years. Your doctor will then replace the battery in a short outpatient procedure that takes about an hour.

The RNS system is always on, constantly monitoring brain activity and responding to abnormal signals that may trigger a seizure. The result is an almost immediate reduction in seizures, and the positive effect increases as time goes on.

One year after surgery, seizures typically reduce by about 65 percent. At three years after surgery, the average seizure reduction is more than 80 percent.

RNS eventually leads to longer periods of time with no seizures at all. Around one-third of people who have RNS report no seizures for three months or longer, and about 16 percent have total seizure freedom within three to six years. Research suggests that RNS stimulation may even retrain the brain’s network of nerves over time in a way that permanently reduces seizure activity.

Most people report improved quality of life and better health as a result of having fewer seizures, along with better memory and less anxiety.

Like all surgical procedures, RNS comes with some risk. In rare cases, people experience: 

• Bleeding
• Decreased seizure control
• Infection
• Problems with the device or leads working properly

At our level 4 Comprehensive Epilepsy Center, Penn Medicine provides the most advanced epilepsy treatments available.

People who come to Penn for RNS treatment choose us for our:

• Personalized care: Our epilepsy team has expertise in all available treatments for seizures. We work to understand your unique needs and recommend the best options for your symptoms and preferences.
• Research-backed therapies: Our epileptologists and neurosurgeons are leaders in neuroimaging and implantable devices for people with epilepsy. As part of an academic medical center, our team also includes active researchers involved in advancing the field. We quickly learn and apply the most effective, innovative treatment solutions backed by research.
• Innovative brain-mapping techniques: Our neurosurgeons use the most advanced neurosurgical guidance systems, such as the robotic stereotactic assistant (ROSA®) and the ClearPoint® system. These tools ensure the most precise and safe placement of RNS stimulation electrodes. This technology minimizes discomfort and side effects and gets you the best results.