Epilepsy is a neurological (brain) disorder that causes repeated seizures without a known cause, or unprovoked.

A seizure happens when a rush of abnormal activity in your brain triggers unusual behavior or sensations. Epilepsy is defined as two or more unprovoked seizures occurring at least 24 hours apart.

Epilepsy is usually treated by medications called antiepileptics or anticonvulsants. However, as many as 30% to 40% of people continue to have seizures despite taking these medications. This is called intractable (drug-resistant) epilepsy.

There are quite a few treatment options for intractable epilepsy, including:

Another treatment option for intractable epilepsy is called responsive neurostimulation (RNS). Keep reading to learn about RNS — the procedure, its benefits and risks, costs, and other useful information.

RNS uses a smart device, called a neurostimulator, that’s implanted under your scalp inside your skull. It operates similarly to a heart pacemaker. A neurostimulator continuously monitors your brain activity through tiny electrodes placed either on the surface or inside the region of your brain responsible for seizures.

When the device identifies brain activity consistent with seizures, it delivers a small amount of electrical current to your brain to stop, shorten, or even prevent the seizure.

The benefits of RNS include:

  • You don’t need to surgically remove parts of your brain to implant the RNS device. (Surgery is still needed to place a neurostimulator in your skull, but it’s considered much less risky.)
  • RNS is reversible. The implant can be removed if necessary.
  • RNS is adjustable. A neurostimulator learns what is going on in your brain, and its settings can be tailored to your particular condition.
  • You can’t feel the stimulation. There’s no pain or any unusual sensations associated with the device once it’s implanted.

Note that you need to continue taking your antiepileptic medications with the RNS implant. At some point, you may be able to decrease the dosage of your antiepileptic medications after seizures have stabilized with the RNS device.

The good news is that RNS isn’t associated with many risks and rarely causes side effects.

RNS surgery to implant the device can potentially cause some side effects, but they’re still not very common. They include:

RNS therapy doesn’t cure epilepsy, but it does help many people with epilepsy control their seizures. Let’s discuss the data that speaks for RNS effectiveness.

A 2020 real-world study followed 150 people with RNS implants for several years. Researchers discovered that the effectiveness of RNS increased with time:

  • After the first year, the median decrease in seizure frequency was 67%.
  • After the second year, it was 75%.
  • After at least 3 years, it was 82%.

In addition to lowering the frequency of seizures, there are other benefits of RNS. According to a recent review of studies, RNS can:

  • lower the risk of unexpected death from seizures
  • improve quality of life
  • enhance cognitive (thinking) function

Before surgery, your doctor will run diagnostic tests to pinpoint the location of seizure activity in your brain. The results of these tests help them figure out how many electrodes to use and where to place them in your brain.

The device implantation procedure is performed under general anesthesia and usually takes around 3 to 4 hours. The surgeon will make at least one incision in your scalp and skull to place the neurostimulator and electrodes connected to it. The RNS device will most likely be implanted on the side and toward the back of your head.

After the procedure, you can expect to stay in the hospital for 1 or 2 nights. No bed rest is required after surgery, and you can return to your daily activities within a few days.

Currently, the battery life of the latest model of RNS device is more than 10 years. This means the procedure will have to be repeated before then.

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Illustration of an RNS neurotransmitter placed on the brain. Illustration by Alyssa Kiefer.

The RNS therapy has been approved by the Food and Drug Administration (FDA) since 2014.

You can be a candidate for this treatment if you:

  • have focal (also known as partial) seizures
  • are at least 18 years old
  • take antiepileptic medications
  • continue to have seizures despite trying at least two different medications
  • either can’t have epilepsy surgery to remove the affected part of the brain or the surgery hasn’t worked for you

RNS device implantation is an expensive procedure. The total cost varies, but you can expect to pay around $50,000 for this treatment. However, according to a recent study, RNS is cost-effective in the long run. Compared with using medications alone, it can save you as much as $46,000 after 9 years.

Check with your insurance policy if RNS therapy is covered.

Although epilepsy is usually treated by medications, there are a few alternative treatments for those with intractable epilepsy. One of these approaches is vagus nerve stimulation (VNS). It’s similar to RNS because it also uses a neurostimulator that sends electric impulses to your brain. However, there are some key differences:

  • VNS neurostimulator is implanted into your chest
  • it stimulates the brain through your vagus nerve
  • rather than targeting a specific part of your brain, it stimulates the brain as a whole
  • it has a number of side effects, including hoarseness, throat pain, and coughing.

Despite these important differences, studies suggest that both VNS and RNS are effective approaches for the treatment of epilepsy. Speak with a doctor to determine which of them is best for you.

After the RNS implant is installed, doctors will give you a remote monitor, which is essentially a specialized laptop. It lets you download data from the neurostimulator and send it to your doctor. They’ll use this information to fine-tune the system’s settings at future appointments.

The RNS system comes with a special magnet that allows the neurostimulator to record brain activity when you swipe it over the implant site on your head. Doctors will ask you to use this magnet when you have a seizure to record brain activity. You can also use the magnet to temporarily stop the neurostimulation.

You’ll have regular follow-up appointments with a doctor to ensure that the system is working properly and to fine-tune its settings. They’ll gradually become less frequent as the system gets adjusted to your condition.

Important health notice

After the device is installed, you must avoid certain medical procedures because they can activate the device, resulting in severe brain injury and even death. These include:

RNS uses a device called a neurostimulator to monitor, stop, or prevent seizures using small amounts of electrical current delivered to your brain. Although it doesn’t cure epilepsy, it’s been shown to decrease the frequency of seizures over time.

You’re eligible for RNS if you’re 18 or older, have intractable epilepsy with focal seizures, and can’t have epilepsy surgery. You’ll have to continue taking your antiepileptic medications with this treatment.