The Food and Drug Administration on Thursday approved an implantable brain-stimulating device for patients with hard-to-treat epilepsy.
The agency said it cleared Neuropace's RNS Stimulator to reduce seizures in epilepsy patients who have not responded well to medications.
The device is implanted in the skull beneath the scalp and attaches to one or two wires that send an electrical current to parts of the brain thought to cause seizures.
The RNS Stimulator is the second device the FDA has approved to treat epilepsy, a neurological disorder that causes mental and physical problems. Cyberonics' VNS Therapy system is also approved for epilepsy, though it works by stimulating a different nerve.
About 3 million people in the U.S. have epilepsy and 40 percent of them continue to experience symptoms despite drug treatment, according to the Epilepsy Foundation.
Neuropace is based in Mountain View, Calif.