Abstracts

A multi-center clinical feasibility investigation was designed to assess the safety and explore evidence for efficacy of a cranially based implantable, programmable responsive neurostimulator (RNS system[reg]) to treat adults with medically intractable partial onset seizures. Adults with medically intractable partial onset seizures with an epileptogenic onset zone previously localized by standard diagnostic testing, were medically and psychiatrically stable, and did not have a history of nonepileptic seizures, primarily generalized seizures, or status epilepticus within the preceding year. Seizure frequency was recorded in daily diaries and seizure severity was evaluated by the Liverpool Seizure Severity Scale. Subjects with [underline][gt][/underline]4 disabling simple partial (SP) sensory or motor seizures, CPS or GTC seizures over 3 consecutive prospective 28-day periods were qualified to receive the RNS device, which was cranially implanted and connected to up to 2 leads containing 4 electrodes each (subdural or depth). Placement of the electrodes was determined by the investigational team. With 28 days post-op, subjects received neurostimulation in response to investigator identified epileptogenic discharges (in an open design). Safety data was monitored continuously and efficacy data was analyzed for 3-28 day periods following the 28 days post-op. The responder rate ([underline][gt][/underline] 50% reduction in seizures) was 43% for CPS and 35% for total disabling seizures (SP motor, CPS and GTC). The mean reduction in total disabling seizures, as analyzed by the generalized estimating equation (Poisson distribution), which controls for seizure variability, was significant at p=0.0006. Seizure severity was significantly reduced (p[lt]0.0001). There were no serious device related adverse events and responsive neurostimulation was well tolerated. A clinical feasibility investigation of a the RNS system demonstrated a significant reduction in the frequency and severity of CPS and total disabling seizures. The safety experience was excellent. Responsive cortical stimulation utilizing an implantable programmable RNS may provide a safe and efficacious treatment for adults with medically intractable partial onset seizures. (Supported by NeuroPace, Inc.)