Electrical activity in the brain is monitored by the battery powered device which is implanted in the cranium. If any abnormal activity is detected, electrical impulses are sent to the seizure focus in the brain via leads, and this assists in preventing the onset of a seizure.
The RNS System also comprises of a programmer for physicians where they can program the detection and stimulation parameters for the implanted device non-invasively. They can also take a look at the patients' electrocorticogram (ECoG) in real time and upload previously recorded ECoGs stored on the RNS implant.
Results have pointed to benefits to the tune of a 37.9% reduction in seizure frequency for subjects with active implants. More than 50% of people experienced a reduction in seizures of 50% or more.
"The RNS System is indicated for use as an adjunctive therapy in reducing the frequency of seizures in individuals 18 years of age or older with partial onset seizures who have undergone diagnostic testing that localized no more than two epileptogenic foci, are refractory to two or more antiepileptic medications, and currently have frequent and disabling seizures."