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RNS® System (hereinafter referred to as RNS System) is medical device for epilepsy treatment.<ref name="neuropaceAbout_the_technology">NeuroPace. About the technology. NeuroPace, Inc. [online]. © 2016. Available online at: http://www.neuropace.com/the-rns-system/ (Retrieved 4.11.2016)</ref> It can monitor and stimulate brain activity, for it is deep brain stimulation device. It is manufactured by privately held company named NeuroPace, which is located in Montain View, California.<ref name="BusinessWirePhoenixConference">NeuroPace RNS® System Honored With Prestigious Award At The 22nd Annual Phoenix Conference. Business Wire: A Berkshire Hathaway Company [online]. 2015, Nov 4. Available online at: http://www.businesswire.com/news/home/20151104005381/en/NeuroPace-RNS%C2%AESystem-Honored-Prestigious-Award-22nd (Retrieved 4.11.2016)</ref> Therapy The therapy with RNS System consist consists in reducing the frequency of seizures in individuals<ref name="NeuropaceSystemUserManual"/>, who have partial-onset, medically refractory (drug resistant) epilepsy.<ref name="NCBI">THOMAS, G.P., JOBST, B.C. Critical review of the responsive neurostimulator system for epilepsy. The National Center for Biotechnology Information [online]. 2015, Oct 1. Available online at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4598207/ (Retrieved 4.11.2016)</ref> Those patients are treated with the RNS System, when they have no more than two epileptogenic foci (epileptogenic focus is the source or starting point of the seizures) and are resistant to more than two antiepileptic medications. The RNS System is thus only for medical prescription.

* RNS Neurostimulator, which is a responsive electrical stimulation medical device (battery powered and microprocessor controlled) <ref name="NeuropaceSystemUserManual"/> Responsive electrical stimulation is a new approach to treating treat epilepsy and RNS System is the first device to provide it. <ref name="epilepsyResponsiveNeurostimulation>SIRVEN, J.I. Responsive Neurostimulation. Epilepsy Foundation [online]. 2014, May. Available online at: http://www.epilepsy.com/learn/treating-seizures-and-epilepsy/devices/responsive-neurostimulation (Retrieved 4.11.2016)</ref> RNS Neurostimulator indicates and records certain patterns in the brain (electrocoticographic, ECoG patterns), which caused causes seizures. Then delivers short trains of current pulses through the leads to interrupt those patterns. Each stimulation can contain two bursts. Neurstimulator must be implanted in the skull together with leads.<ref name="NeuropaceSystemUserManual"/> The Neurostimulator should work for about 2 to 3.5 years , before battery power is drained. It has is size of 28 x 60 mm, so it is relatively smalldevice.<ref name="NeuropaceSystemPatientManual">NeuroPace. NeuroPace® RNS® System

* NeuroPace Leads are placed in the brain and are connected to Neurostimulator. One lead contains four electrodes. There are two kind of these leads. First, the Cortical Strip Leads are intended for to subdural implant and are available in 15, 25 or 35 centimenters length. Four electrodes in leads are spaced 10 millimenters apart from each other. Second, the Depth Leads are intended for implant into brain. They are in four combinations - 30 centimeter length, 10 millimeter electrode spacing; 30 centimeter length, 3.5 millimeter electrode spacing; 44 centimeter length, 10 millimeter electrode spacing or 44 centimeter length, 3.5 millimeter electrode spacing.<ref name="NeuropaceSystemUserManual"/>

Main purpose of the RNS System is treating to treat medical condition called epilepsy. The goal of the RNS System is not enhance human´s cognitive capabilities.

The RNS System is medical device to treat epilepsy. It is not designed for enhancing human capabilities, although it was demonstrated, that the RNS System has no adverse cognitive effect in epileptics. <ref name="BusinessWirePositiveEffects">NeuroPace RNS® System Associated with Positive Effects In Memory and Language for People Living with Partial Onset Epilepsy. Business Wire: A Berkshire Hathaway Company [online]. 2015, Oct 20. Available online at: http://www.businesswire.com/news/home/20151020005454/en/NeuroPace-RNS%C2%AE-System-Positive-Effects-Memory-Language (Retrieved 4.11.2016)</ref> In several cases it come even comes to some improvements in the cognitive capabilities. Although these findings are inconclusive for they result from very various data.<ref name="AES_ResponsiveNeurostimulation_and_Cognition">SPENCER, D. Responsive Neurostimulation and Cognition. Epilepsy Currents [online]. 2016, March-April, Vol. 16, No. 2, pp. 98-100. Available online at: http://www.epilepsycurrents.org/doi/full/10.5698/1535-7511-16.2.98 (Retrieved 4.11.2016)</ref> A possible explanation of the alleged cognitive enhancement may rest in reduced seizures. But this is not enhancement of the sort, but rather "side effect" of the successful treatment of epilepsy.

Epilepsy or “seizure disorder” is a chronic disorder, which cause causes unpredictable seizures of all kinds, which might have all sorts of other consequences. Epilepsy usually has not simple or known cause.<ref name="epilepsyWhatIsEpilepsy">SIRVEN, J.I. What Is Epilepsy? Epilepsy Foundation [online]. 2014, Jan. Available online at: http://www.epilepsy.com/learn/epilepsy-101/what-epilepsy (Retrieved 4.11.2016)</ref> It might be caused some illness (for example brain tumors or Alzheimer’s disease<ref name="NIH_The_Epilepsies_and_Seizures">National Institute of Neurological Disorders and Stroke. The Epilepsies and Seizures. National Institute of Neurological Disorders and Stroke [online]. 2015, Aug, NIH Publication No. 15-156. Available online at: http://www.ninds.nih.gov/disorders/epilepsy/curing_the_epilepsies_brochure.pdf (Retrieved 4.11.2016)</ref>, brain damage, abnormal brain development, genetic mutation (de novo mutations) etc..<ref name="NIH_The_Epilepsies_and_Seizures"/> But those causes might be very diverse. Epilepsy always arises from brain and is bound to sudden abnormal brain electrical activity.<ref name="NIH_The_Epilepsies_and_Seizures"/> Clusters of neurons might fire signal faster than normal, which is as many as 500 times a second. That electric activity then cause causes seizure.<ref name="NIH_The_Epilepsies_and_Seizures"/> This medical condition is considered, when individual has at least two or more unprovoked seizures separated by 24 hours.<ref name="NIH_The_Epilepsies_and_Seizures"/> In the United States suffer from epilepsies up to 2.3 million adults and more than 450,000 children. <ref name="NIH_The_Epilepsies_and_Seizures"/> Without satisfactory seizure control still remain 15-40% of all patients.<ref name="Neurostimulation for the Treatment of Epilepsy">Wu C., Sharan A.D. 2012. Neurostimulation for the Treatment of Epilepsy: A Review of Current Surgical Interventions. Neuromodulation 2012; e-pub ahead of print. DOI: 10.1111/j.1525-1403.2012.00501.x</ref>

There are many possible triggers of seizures in epilepsy.<ref name="NIH_The_Epilepsies_and_Seizures"/> The most common perceived triggers are: missing medication (40.9%), emotional stress (31.3%), sleep deprivation (19.7%), fatigue (15.3%), missing meals (9.1%), fever (6.4%), and smoking (6.4%). Data was obtained form 405 patinets.<ref name="Perceived trigger factors of seizures in persons with epilepsy">BALAMURUGAN, et al. Perceived trigger factors of seizures in persons with epilepsy. Elsevier Inc., 2013, Vol. 33, Iss. 9, pp 743 - 747. Available online at: http://www.seizure-journal.com/article/S1059-1311(13)00177-5/pdf (Retrieved 4.11.2016)</ref> Only around 3% of epileptics have a photosensitive epilepsy. That is the kind of epilepsy, which is triggered by certain visual patterns, such as flashing lights.<ref name="Photosensitivity and Seizures">SHAFER, P.O., SIRVEN, J.I. Photosensitivity and Seizures. Epilepsy foundation [online]. 2013, Nov. Available online at: http://www.epilepsy.com/learn/triggers-seizures/photosensitivity-and-seizures (Retrieved 5.12.2016)</ref> There are more than 30 different types of seizures, but generally they are divided into the two major groups – the focal seizures, which originate only in one part of the brain, and the generalized seizures, which come from both sides of the brain.<ref name="NIH_The_Epilepsies_and_Seizures"/> These seizures might look very different, they might or might not cause loss of consciousness, or a muscle´s massive contractions. It might also appear, for example in the intense feeling of déjà vu. Epilepsy has also many various types, for example the absence epilepsy, the frontal lobe epilepsy, the temporal lobe epilepsy (most common form in focal seizures) or the neocortical epilepsy.<ref name="NIH_The_Epilepsies_and_Seizures"/>

Epilepsy has also some risks associated with the life-threatening conditions, such as "status epilepticus" and "sudden unexpected death". However these cases are very relativelly rare. More common risks appear are appearing in connection with the injury during seizures.<ref name="NIH_The_Epilepsies_and_Seizures"/>

There are several possible scenarios with regard to the treatment of epilepsy. Epilepsy might be treated with medications (for example, Carbamezepine, Diazepam, Lorazepam, Topiramate etc.), diet (a hight-fat, very low carbonhydrate ketogenic diet), surgery (only if focal seizures persist after at least two medications or if it is identifiable brain lesions) or devices just like the RNS System. There are some different possible devices to treat the epilepsy, for instance, the Vagus nerve stimulator (approved by the FDA in 1997) or the experimental devices not approved by the FDA: the trigeminal nerve stimulation or the transcutaneous magnetic stimulation.<ref name="NIH_The_Epilepsies_and_Seizures"/>

The treatment with the RNS System provides responsive cortical stimulation via neurostimulator connected to depth or subdural cortical strip leads. They are placed in the brain based on seizure focus. The neurostimulator continually scans electrocorticographic activity, detects abnormal activity and provides stimulation. The physician regulates and optimizes the parameters for each patient individually.<ref name="MorrellResponsive cortical stimulation">MORRELL, M.J. Responsive cortical stimulation for the treatment of medically intractable partial epilepsy. Neurology. Neurology, 2011, Sep 27, vol. 77, no. 13, pp. 1275-1304. ISSN 0028-3878. </ref> It always depends upon where in the brain is the focus of epilepsy. Seizures might come from different cortical location, that include temporal, frontal, centroparietal, or occipital lobe regions. <ref name="epilepsyFamilial Focal Epilepsy">PANAYIOTOPOULOS, C.P. Familial Focal Epilepsy with Variable Foci. Epilepsy Foundation [online]. 2005, Jan. Available online at: http://www.epilepsy.com/information/professionals/about-epilepsy-seizures/familial-autosomal-dominant-focal-epilepsies-2 (Retrieved 4.11.2016)</ref> But the RNS System is adjust adjusted only for at the most two foci of seizures.<ref name="NeuropaceSystemUserManual"/>

So the treatment with the help of the RNS System is not intended for everyone. The patient must fulfil several conditions: he must have the focal (partial)<ref>According to International League Against Epilepsy (ILAE) is the concept of “partial” replaced by “focal” to unified terminology of epilepsies</ref> seizures, have has average three or more disabling seizures per month (over the three most recent month), and he have has to be resistant to the medications or diet (drug resistant is in the case of RNS System defined according to ILAE as a failure to control seizures after two seizures medications).