Summary: Vagus nerve stimulation (VNS) has demonstrated a significant anticonvulsant effect in preclinicalstudies, in pilot studies in humans, and in the acute phaseof a multicenter, double‐blinded, randomized study. After completion of a 14–week, blinded, randomized study, with 31 receiving high (therapeutic) VNS and 36 receiving low (less or noneffective) VNS, 67 patients elected tocontinue in an open extension phase. During the extension phase, all 67 patients received high VNS. Seizurefrequency during the 3‐month treatment blocks was compared with a 12–week baseline. For both groups, all periods of high VNS demonstrated a significant decrease inseizure frequency (p < 0.01 level) as compared with baseline. For the 16–18–month period of VNS, data wereavailable for 26 of the 31 patients randomized to highVNS. This group achieved a 52.0% mean seizure frequency percentage réduction as compared with baseline. For those converted from low to high VNS, data wereavailable for 24 of the 36 patients at the 16–18‐month timeperiod. This group reported a mean seizure frequency percentage reduction of 38.1% as compared with baseline. No significant change in the safetyhde effect profilewas reported during longterm followup. The previouslyreported side effects of hoarsenesslvoice change, coughing, and paresthesia (sensation in neck and jaw) continued to occur during VNS. These side effects were well tolerated. During the follow‐up period, 1 patient died of thrombotic thrombocytopenic purpura (TTP) and 5 patients discontinued treatment because of unsatisfactory efficacy.
