Two-year outcomes of epicranial focal cortex stimulation in pharmacoresistant focal epilepsy.

Objective: This study was undertaken to report on the long-term safety and efficacy of epicranial focal cortex stimulation (FCS) using the EASEE device as adjunctive neuromodulatory therapy in improving seizure control in adults with pharmacoresistant epilepsy originating from one predominant epileptogenic zone.

Methods: Prospective open-label follow-up of patients from the EASEE II and PIMIDES I clinical trials was done for a period of 2 years after the epicranial implantation of the EASEE electrode and stimulator device.

Results: Thirty-three patients underwent device implantation, and stimulation was activated in 32 patients. Of these, 26 patients continued stimulation up to 2-year follow-up and provided seizure diary data for efficacy analysis. The 50% responder rate at 2-year follow-up was 65.4% (95% confidence interval = 44.3-82.8), corresponding to a median seizure frequency reduction of 68%. Patients reported improved health-related quality of life. Tolerability was excellent, and there were no severe adverse events considered to be related to implantation or stimulation, nor were adverse effects on mood or cognition reported.

Significance: Results of the 2-year follow-up show that epicranial FCS is well tolerated by patients while providing improved seizure control in the long term. It thus offers a minimally invasive treatment option for patients with a predominant epileptic focus.