A treatment can consist of up to five different stimulation parameters delivered sequentially. After each stimulation, the device tries to detect further epileptiform activity; it will deliver the next stimulation if such activity is present, or cease stimulation if there is no epileptiform discharge.
In a feasibility study of 65 patients, the system was deemed safe. In a preliminary analysis of 24 patients, the response rate (defined as a seizure reduction of at least 50%) was 43% for complex partial seizures and 35% for total disabling seizures, which included simple partial motor, complex partial, and secondarily generalized tonic-clonic seizures (Neurotherapeutics 2008;5:68–74).
NeuroPace is recruiting up to 240 patients with refractory partial-onset seizures for a randomized, sham-controlled trial of the system, with 2–3 years of follow-up. During the initial 4-month double-blinded phase, half of the patients will have the system turned on and half of them will have it remain off, after which all of the patients will receive stimulation.