The European regulatory authority, called CE-Mark, has approved Medtronic’s deep brain stimulator (DBS) as therapy for uncontrolled partial and secondarily generalized seizures. Approval was based upon a randomized controlled trial of implantation in 110 people in the US (Fisher and associates, Electrical stimulation of the anterior nucleus of thalamus for treatment of refractory epilepsy." Epilepsia, 2010, 51:899–908). During the blinded 3 months of the trial, seizures were reduced in the stimulated group by 40% relative to the 3 months before implantation. The group given sham stimulation at zero volts improved only 14.5%, and this group difference was statistically significant. After three months, stimulation was turned on in all patients, and average improvement was 58% by two years of stimulation. Overall, 14% of people became seizure-free for six months or more. Several secondary measures of improvement, however, failed to show benefit in the stimulated group. No deaths or symptomatic brain hemorrhages were attributed to stimulation. Adverse event reports suggested the possibility of worsening memory or depression in the stimulated group, but objective testing disclosed no differences.

Because of the CE-Mark approval, DBS will soon be available in Europe and in other countries that follow the CE-Mark recommendation. The US FDA has indicated that it wishes to see more data before approving DBS for epilepsy in the United States.