RNS for IGE: information for referring physicians.

This page is for physicians who have a patient with idiopathic generalized epilepsy that hasn't responded to medication, and who want to know more about bilateral centromedian thalamic (CM)-RNS.

The MGH surgical team is Dr. Mark Richardson and Dr. Pranav Nanda. Programming and long-term follow-up can be shared with your practice or handled by the MGH Neurology RNS Clinic under one of four models described below.

If you're already comfortable that your patient meets criteria, jump to the referral form at the bottom.

Who to think about.

The patients to keep in mind are the ones whose epilepsy looks generalized (primary generalized tonic-clonic, absence, or myoclonic seizures) and whose seizures continue despite reasonable trials of broad-spectrum antiseizure medications.

In practice, that usually means:

  • A diagnosis of IGE in the JME / JAE / CAE / GTCA spectrum, or IGE not otherwise classified

  • Generalized spike-wave or polyspike-wave on EEG with an otherwise normal background

  • A structurally normal MRI

  • Continued disabling seizures despite at least two appropriately chosen, well-tolerated medications

You don't have to be certain. If most of these are true and your patient is frustrated with where things stand, send them. Part of what we do in evaluation is confirm the diagnosis. Sometimes apparent IGE turns out, on review, to be focal epilepsy with rapid generalization, which can still be treated well with RNS.

What the therapy does.

Bilateral CM-RNS is responsive neurostimulation delivered through two electrode leads placed in the centromedian nucleus of the thalamus, one on each side. The implanted neurostimulator senses electrocorticographic activity from the leads and delivers brief stimulation when it recognizes the patient's specific seizure pattern.

For focal epilepsy, RNS has been on the market for years, and many epileptologists already program it. Two things are new here: the indication is generalized epilepsy, and the target is the bilateral centromedian nucleus rather than cortical leads at a focal onset zone.

Dr. Richardson performed the very first bilateral CM-RNS for IGE in 2015, over ten years ago! MGH now has one of the nation’s most experienced RNS programs for both adults and children. We have provided RNS Therapy to children as young as 4 years of age.

What you ask for when you refer.

On the referral form, you'll be asked to pick one of two pathways:

Option 1: Refer for full evaluation. We do the whole workup: epileptology consult, video-EEG if not already done, advanced imaging as needed, neuropsychology, and a multidisciplinary discussion. If bilateral CM-RNS isn't the right next step, we tell you what we'd recommend instead.

Option 2: Refer directly for surgical consultation. If you have completed the workup and want the patient routed straight to Dr. Richardson and Dr. Nanda to discuss implantation, we are happy to receive the data and see the patient promptly.

If your patient proceeds to implantation under Option 2, you'll also pick how programming should be handled. There are four models from which you can choose:

Model A: Programming returns to you. After implantation, programming is handled by you. We're available for case discussion when you want it, but the patient doesn't routinely come back to our clinic.

Model B: Initial programming with us, then to you. The patient comes to our neurosurgery clinic for the first programming visit, where we set up detections and initial stimulation parameters. After that, programming is handed over to you.

Model C: Programming stays with our neurosurgery clinic, medications stay with you. The patient continues at our neurosurgery clinic for programming long-term. You continue to manage medications and routine epilepsy follow-up. We coordinate when changes on either side affect the other.

Model D: Programming stays with MGH Neurology, medications stay with you. The patient is referred to our MGH Neurology RNS Clinic for programming long-term. You continue to manage medications and routine epilepsy follow-up.

The models can cross whenever needed. A patient who starts in Model C can transition to Model B once you've built comfort with programming. A patient in Model A can come back to us if a difficult programming question comes up.

What to tell your patient about timing and outcomes.

RNS improves with time. Early months are spent establishing how the device detects each patient's seizures; later programming refines how it responds. Patients who go in expecting an on/off switch are disappointed; patients who go in expecting a therapy that gets better over months are usually not.

The NAUTILUS trial was the first large, high-quality randomized study of this treatment for generalized epilepsy. It included 87 people (age 12 and older) at 23 U.S. centers who still had seizures despite medication. Key results after about 18 months:

  • About 77% fewer generalized tonic-clonic seizures, on average.

  • About 6 out of 10 people had their tonic-clonic seizures cut at least in half.

  • About 4 out of 10 people had no tonic-clonic seizures at all at that point in time.

  • Days with any type of generalized seizure dropped by about 77%.

  • More than 9 out of 10 patients felt their condition had improved overall.

How to refer.

Please fill out the referral form below, which also allows you to refer for focal epilepsy surgery. Our goal is to respond within 24 hours.