By: Catherine Joachin
Responsive Neurostimulation (RNS)
What is responsive neurostimulation?
Responsive Neurostimulation (RNS) is a medical device designed to treat drug-resistant focal epilepsy by suppressing seizures through real-time electrical stimulation (Cleveland Clinic, 2025).
How does it work?
RNS uses a small neurostimulator surgically implanted into the skull to continuously monitor brain activity. This neurostimulator is equipped with thin electrodes that deliver electrical pulses directly to the seizure foci in response only to patient-specific ictal electrocorticography (ECoG) patterns, making RNS a closed-loop treatment approach (Hartshorn & Jobst, 2018). This is meant to stop, shorten or prevent the seizure as progressive electrical stimulation diminishes the brain’s capacity to generate seizures (Cleveland Clinic, 2025). Pattern recognition is enabled by specially trained doctors capable of configuring the RNS program to capture patient’s unique seizure activity (Hartshorn & Jobst, 2018).
RNS does not require surgical removal of brain tissue and the device can be removed if needed, meaning that the treatment is reversible (Rao & Rolston, 2023).
Outcomes
Adult patients with drug-resistant epilepsy who participated in randomized, controlled RNS clinical trials reported experiencing less disabling seizures, with the average patient having 75% fewer seizures after 9 years (Nair et al., 2020). RNS is associated with improved quality of life and cognitive function in stimulated cortical seizure foci (Skarpaas, Jarosiewicz & Morell, 2019). These trials have also demonstrated that long-term RNS treatment is tolerable and acceptably safe (Skarpaas, Jarosiewicz & Morell, 2019).
Limitations
Although innovative, RNS is not without limitations. RNS is an adjunctive therapy, meaning that it is an added treatment to be used alongside medications in drug-resistant focal epilepsy, and it does not cure epilepsy, but simply manages it (Nair et al., 2020; Cleveland Clinic, 2025).
Seizure reduction is not immediate, it can take several months to notice any change and years to reach optimal results (Hartshorn & Jobst, 2018). In a randomized controlled RNS trial with 256 participants, median seizure frequency reduction after a year of implantation was 44%, 53% at 2 years, and ranged between 50-66% at years three to six, showing progressive improvement (Skarpaas, Jarosiewicz & Morell, 2019)
Moreover, there is little data on the application of RNS treatment in children as it not currently FDA-approved in individuals below 18 years of age, offering little date on its safety efficacy in pediatric populations (Gouveia et al., 2024).
Conclusion
Responsive neurostimulation is a complementary treatment approach to anti-epilepsy drugs offering real-time seizure detection and subcortical stimulation for more precise epilepsy management for adults with medically intractable seizures.
References
Cleveland Clinic. (2025, January 9). Responsive neurostimulation. Cleveland Clinic. https://my.clevelandclinic.org/health/procedures/responsive-neurostimulation
Gouveia, F. V., Warsi, N. M., Suresh, H., Matin, R., & Ibrahim, G. M. (2024). Neurostimulation treatments for epilepsy: Deep brain stimulation, responsive neurostimulation and vagus nerve stimulation. Neurotherapeutics, 21(3), Article e00308. https://doi.org/10.1016/j.neurot.2023.e00308
Hartshorn, A., & Jobst, B. (2018). Responsive brain stimulation in epilepsy. Therapeutic Advances in Chronic Disease, 9(7), 135–142. https://doi.org/10.1177/2040622318774173
Malaga, M., Modiano, Y., & Haneef, Z. (2025). Neuropsychological and neurobehavioral outcomes of responsive neurostimulation in epilepsy: A systematic review and meta‐analysis. Epilepsia (Copenhagen), 66(10), 3585–3601. https://doi.org/10.1111/epi.18505
Nair, D. R., Laxer, K. D., Weber, P. B., Murro, A. M., Park, Y. D., Barkley, G. L., Smith, B. J., Gwinn, R. P., Doherty, M. J., Noe, K. H., Zimmerman, R. S., Bergey, G. K., Anderson, W. S., Heck, C., Liu, C. Y., Lee, R. W., Sadler, T., Duckrow, R. B., Hirsch, L. J., … Morrell, M. J. (2020). Nine-year prospective efficacy and safety of brain-responsive neurostimulation for focal epilepsy. Neurology, 95(9), e1244–e1256. https://doi.org/10.1212/WNL.0000000000010154
Rao, V. R., & Rolston, J. D. (2023). Unearthing the mechanisms of responsive neurostimulation for epilepsy. Communications Medicine, 3(1), Article 166. https://doi.org/10.1038/s43856-023-00401-x
Skarpaas, T. L., Jarosiewicz, B., & Morrell, M. J. (2019). Brain-responsive neurostimulation for epilepsy (RNS® System). Epilepsy Research, 153, 68–70. https://doi.org/10.1016/j.eplepsyres.2019.02.003
UCSF Health. (2024, April 12). Responsive Neurostimulation. ucsfhealth.org. https://www.ucsfhealth.org/treatments/responsive-neurostimulation
