By: Dr. Sharon Elza Raju, BDS, MHA, LSSGB, PMEC and Natalie L. Boehm, MBA, RBLP-T
An estimated thirty percent of patients have refractory epilepsy, or drug resistant epilepsy. When a patient has tried at least two medications and seizures still cannot be controlled, surgery is an option for some. For those who are considering surgery, one option they may be eligible for is an responsive neurostimulation system, also know as the RNS® system.
What is the RNS® system?
According to the Epilepsy Foundation, the RNS® System is a smart device that is adjustable and reversible. Where it is placed and how it is used is tailored to each person. It learns what is going on in a person’s brain, and settings can be adjusted for each person. (Epilepsy Foundation of America, 2018).
The RNS® System is designed to work in 3 key ways:
- Monitor brain waves at the seizure focus, all the time – even during sleep.
- Detect unusual electrical activity that can lead to a seizure.
- Respond quickly (within milliseconds) to seizure activity by giving small bursts or pulses of stimulation.
(Epilepsy Foundation of America, 2018)
The RNS has two main parts
- A neurostimulator device placed in the skull (bone covering the brain) that can be programmed to record and stimulate brain activity.
- Thin wires or “leads” are placed on the surface of the brain in the area where seizures begin (seizure focus). They are then connected to the neurostimulator device.
(Epilepsy Foundation of America, 2018)
Who qualifies for an RNS® System?
The RNS is used to control seizures in patients who are aged 18 years and over. The patient has tried at least two anti-convulsant medication, but continues to have frequent and disabling focal onset seizures that are coming from one or two areas of the brain (Neuropace, 2021).
How well does the RNS therapy work?
The RNS System lowers the number of seizures in the many people who have used this.
• About half of people with RNS will have a positive response.
• On average, seizures decrease by about 50% after 2 years of using RNS.
• The positive effects of RNS seem to increase over time.
• After 7 years, 2 out of 3 people had their seizures cut in half.
• People may also notice changes in quality of life over time
(Epilepsy Foundation of America, 2018)
How often does an RNS device need to be checked?
Neuropace will provide their clients with a RNS® System Patient Manuel which can also be found at:
https://www.neuropace.com/wp-content/uploads/2021/02/neuropace-rns-system-patient-manual.pdf
There are two models of the RNS neurostimulator, the RNS-300M and the RNS-320. According to Neuropace, the RNS-300M stimulator should work 2.6-4.3 years and the RNS-320 should work about 5.1-9.4 years before the battery power is drained (Neuropace, 2020). How fast your battery is drained depends on the model you receive and the setting that your physician places it at. Once the battery is used up, you would have to have the device replaced (Neuropace, 2020).
It is important to communicate with your doctor about how your device is working. If you are having an increase in seizure activity or no improvements, adjustments may need to be made by your physician. Neuropace has set up for their clients a Patient Data Management System (PDMS), which allows patients to collect data and submit it to their physican to make sure the device is working correctly. The PDMS site is available for patients at:
To learn more about the PDMS system if you are going to receive a RNS, the information is available at:
https://www.neuropace.com/wp-content/uploads/2018/01/RNS-System-Programming-Reference-Guide.pdf
Conclusion
The RNS® System is an option for patients who have refractory epilepsy experiencing focal onset seizures. There are two models of the RNS, each lasting different times. It is important to consult with your physician before making a decision if an RNS is right for you. Neuropace provides a lot of information about their product as well as resources for collecting data for the physician once the patient has received one.
Resources:
Epilepsy Foundation (2018). Response Neurostimulation (RNS®System). Epilepsy Foundation of America. Retrieved from: https://www.epilepsy.com/sites/core/files/atoms/files/518RNS_RNS_092418_FINAL.pdf
Iyengar, S. and Shafer, P.O. (2017). Responsive Neurostimulation (RNS). Epilepsy Foundation of America. Retrieved from: https://www.epilepsy.com/learn/treating-seizures-and-epilepsy/devices/responsive-neurostimulation-rns
Neuropace (2021). The RNS®System delivers epilepsy treatment personalized to you. Neuropace. Retrieved from: https://www.neuropace.com/patients/neuropace-rns-system/
Neuropace (2020). RNS® System Patient Manual, For the RNS® Neurostimulator Model RNS-300M and Model RNS-320. Neuropace. Retrieved from: https://www.neuropace.com/wp-content/uploads/2021/02/neuropace-rns-system-patient-manual.pdf
Neuropace (2017). Neuropace, The RNS® System, Clinic Workflow and Programming. Neuropace. Retrieved from: https://www.neuropace.com/wp-content/uploads/2018/01/RNS-System-Programming-Reference-Guide.pdf
UC Health (2021). Responsive Neurostimulation. UC Health. Retrieved from: https://www.uchealth.com/en/treatments/responsive-neurostimulation
