RNS for generalized epilepsy: a guide for patients and families.
If you or someone in your family has a form of epilepsy that hasn't responded to medications, this page is for you. It covers what Drs. Richardson and Nanda would explain in clinic, in plain language.
What is idiopathic generalized epilepsy?
Idiopathic generalized epilepsy, or IGE for short, is a group of related epilepsies that usually start in childhood, the teen years, or young adulthood. The common ones are juvenile myoclonic epilepsy, juvenile and childhood absence epilepsy, and generalized tonic-clonic seizures.
In IGE, seizures don't come from one damaged spot in the brain. They come from networks that involve the whole brain at once, and an MRI of the brain typically looks normal. This is why surgery to remove a piece of brain, which works for some other epilepsies, has never been an option for IGE.
Many people with IGE do well on medication. For the people who don't, the question has always been: what else?
What the RNS System actually does.
The RNS System is a small device that gets implanted under the scalp, with two thin electrode leads placed deep in the brain. The device does two things, continuously:
It listens to the electrical activity in the brain.
When it recognizes the pattern that comes before a seizure, it responds with a brief burst of stimulation, too small to feel, that's designed to disrupt the pattern before a seizure builds.
It's sometimes called a brain pacemaker, but that sells it short. A heart pacemaker runs the same program for everyone. The RNS System gets tuned over time to your specific brain, your specific seizure pattern, and the way that pattern changes as you live with the device. The therapy gets better the longer it's in.
Why we place the electrodes in the thalamus.
If seizures in IGE involve the whole brain, where do you put the electrodes?
The answer turns out to be a structure called the centromedian nucleus of the thalamus. It's a hub deep in the brain that a lot of widespread networks pass through. Stimulating it on both sides is what we call bilateral CM-RNS. That approach lets the device sense and respond from a place with access to the kinds of rhythms that go wrong in IGE.
Dr. Richardson performed the first ever bilateral CM-RNS implantation for IGE in 2015. The experience from that case, and the cases that followed, is what shaped the program we offer now.
What the path through our program looks like.
The path has four parts. There's some flexibility (sometimes we collapse steps if the workup is already complete), but in general, it goes:
1. Evaluation. A careful look at your seizures, your EEG, your MRI, and the medications you've already tried. Sometimes a few additional tests.
2. Decision. We confirm whether bilateral CM-RNS is the right next step; sometimes our neurosurgical team can determine that on our own, and sometimes we require the help of our neurology colleagues. If it isn't the right next step, we will tell you what we'd recommend instead.
3. Surgery. The device is implanted under general anesthesia. Most patients go home after one or two nights in the hospital.
4. Programming and follow-up. The device gets turned on at a follow-up visit and tuned over the months that follow. Improvement usually builds gradually. RNS is a therapy that gets better with time, not one that flips on like a switch.
Common questions.
Will I still need my medications? You should plan on needing medications, although our goal is to get you on as little medication as possible and reduce medication side effects. Many patients are eventually able to reduce medication, and occasionally patients come off medication altogether.
Will I feel the stimulation? Most patients don't. The pulses are brief and low-intensity. They're designed to interrupt the brain's electrical pattern, not produce a sensation. If a sensation is produced during test stimulation, we can avoid those settings for therapeutic stimulation.
How long until I see a benefit? Early programming establishes how the device detects your seizures. Later sessions refine how it responds. Across responsive stimulation in epilepsy, the average benefit at three years is greater than at one. The therapy improves with time.
Is it safe to live with? The RNS System has been implanted in many thousands of patients for other forms of epilepsy and has a well-characterized safety profile. Like any implanted device, it carries surgical risks, and the battery needs to be replaced periodically. We talk through all of this in detail before any decision.
Can I have an MRI? Yes, with specific protocols. You'll get a card and clear instructions to share with any imaging center.
What if it doesn't work for me? The device can be reprogrammed extensively, and the stimulating leads can be repositioned in the brain to different locations. It is very rare for the device to not provide significant benefit, but if a patient ever wanted the device removed, that is safe to do.
What to do next.
Talk to the neurologist who already manages your epilepsy, and ask them to refer you using the physician page on this site.
You may also fill out a self-referral screening form, and our office will contact you.