Jonathan C. Edwards, M.D., director of the Comprehensive Epilepsy Center at MUSC Health, discusses how responsive neurostimulation (RNS) for partial epileptic seizure offers for the first time two-way communication with the brain. Edwards participated in the clinical trial that led to FDA approval of RNS. . The RNS device first records seizure activity and, once the electronic signature of a patient's seizures is identified, is programmed to recognize and disrupt that signature.
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Progressnotes, MUSC’s Medical Magazine JONATHAN C. EDWARDS: What's unique about this particular therapy is this is responsive neurostimulation, which is a little different. The stimulation techniques that we've been using in neuroscience up to this point are mostly a one directional thing. They stimulate on and off throughout the day either to prevent a symptom or improve a symptom, but they're not actually responding to neurological activity. This responsive neurostimulator is a very clever device. It's essentially a small microprocessor that's placed in the patient's skull, and then a couple of small leads or electrodes are placed at the source of the patient's seizures. And for different patients the seizures may be coming from different areas of the brain, so we place these little electrodes that are about the size of a piece of spaghetti at the source of the seizures. And the device will continuously record that electrical activity from the brain, what we call electrocorticography or EEG activity, straight from the brain itself rather than just being recorded from the scalp. Well, that activity is recorded in the little computer that's been implanted. Then the patient is provided with a laptop computer and a little wand, which is just a wireless telecommunication device that's held over it, and it wirelessly loads the information into the laptop. Then the patient can send the information from that laptop through the internet to a secure website. And then we can go into that secure website and look at the electrocorticography, and we can then teach the device to detect the patient's seizures. So it doesn't just load and just record, but the device can be programmed. There's a lot of different methods for detection, and we can adjust over time to find what methods and what settings detect that patient's seizures the most accurately and most reliably and the quickest. Once we have done that then we take it a step further, and we can actually program the device that when a seizure occurs as soon as that seizure is detected-- and this is often even before the patient ever feels anything-- as that electrical signal of a seizure starts, the device will give a little electrical stimulus. And that basically interferes with the progress of the seizure and disrupts the seizure. This really is a treatment for people for whom we can determine where the seizures are coming from and the medicines aren't working, and we can determine where the seizures are coming from, but we can't remove the spot where the seizures are coming from. For many patients with epilepsy, we can do epilepsy surgery. And then you go straight to the source, remove it, and you can get rid of the seizures altogether. But this is for the patients for whom that is not an option, because the epilepsy either is coming from more than one spot. And you can't do a little surgery over here and a little surgery over there. The brain doesn't respond well to that. Or sometimes the epilepsy is coming from a spot that is non-negotiable. It cannot be removed, because there is no backup for that function. One of the reasons I'm so excited about it is first of all, it will help some patients for whom we don't currently have options. But to me the even more exciting thing is the new door that this opens. This is a whole new territory now, because, as I said before, we're now finally having a conversation with the human brain. So this current device can only record and work in two very, very focal areas, but it's just a very, very small step from there in terms of computer technology and mathematics and batteries to be able to treat a much broader area. And so this is opening up an entire new door for treatments, but also for our understanding of the human brain.