Responsive neurostimulation

Responsive neurostimulation is a relatively new treatment modality for refractory focal epilepsy, indicated for patients who have failed two or more seizure medications and have one or two well-localized epileptogenic foci. The RNS System is the first closed-loop neurostimulation device, which detects epileptiform activity, stores electrocorticography samples, and stimulates in response to detections. Class I evidence for its efficacy came from a randomized controlled trial that demonstrated a significant reduction in seizure frequency in the treatment arm. Subsequent studies show increasing benefit over time, with improved quality-of-life scores and no significant worsening of cognition or mood.