Responsive neurostimulation device

Responsive neurostimulation device or RNS system is a responsive direct brain stimulation treatment for adults with medically refractory epilepsy. The RNS System utilizes a neurostimulator implanted in the skull with one or two leads implanted in the brain at the focal points of the seizures.

The RNS system was granted FDA approval on November 14, 2013 for the treatment of adults with partial onset seizures that have not been controlled with two or more antiepileptic drugs.

The neurostimulator is a device that is implanted within the skull by a study physician. The device is powered by a battery and contains custom electronics and software that detects and stores a record of the brain’s electrical activity through the implanted leads. When the device identifies pre-programmed epileptiform activity, it attempts to suppress the seizure by sending a small electrical stimulation through the leads to that portion of the brain. This type of treatment is called closed-loop or responsive stimulation. The study physician has a programmer device while the patient has a Remote Monitor (RM) to provide information from his or her neurostimulator to the study physician.

The physician-operated programmer wirelessly communicates with the implanted RNS neurostimulator. The study physician uses the programmer to look at information stored in the device about the patient’s detections and stimulations. The study physician can also look at records of actual brain electrical activity. This information helps the study physician select the best detection and stimulation settings for a particular patient. The programmer is then used to program the detection and stimulation settings in the neurostimulator.

The RM is used by the patient to provide information to the study physician and to NeuroPace. Patients use a wand to transfer information from the neurostimulator to the RM. Patients then connect the RM to a phone line and information is provided to his or her study physician via proprietary software. The study physician is then able to view the response to the stimulation and decide on the best seizure detection and stimulation settings for the patient.

The system is implanted by a study physician during a surgical procedure that occurs while the patient is asleep. Then the neurostimulator is placed in the skull. After the procedure, the patient will typically stay in the hospital one to three days.

The RNS System is currently in the Long-term Treatment trial to determine how well it can reduce the frequency of uncontrolled seizures. The treatment was evaluated in a pivotal study for adults with medically refractory epilepsy in 33 clinical trial sites across the United States with a total of 191 patients. It is approved for use in clinical research studies and commercially in the United States.

See also

• Electroencephalography (EEG)
• Electrocorticography (ECoG)
• Single-unit recording a method of measuring the electro-physiological responses of single neurons using a microelectrode system

References

• Responsive cortical stimulation for the treatment of medically intractable partial epilepsy. Morrell MJ; RNS System in Epilepsy Study Group. Neurology. 2011 Sep 27;77(13):1295-304
• FDA Advisory Panel Recommends Approval of the NeuroPace RNS® System for Medically Refractory Epilepsy
• (Wayback machine for http://www.seizurestudy.com/InvestigationalTreatment.html) The RNS System Information from a patient who started in the pivotal trial and is now in the long term trials.