Effects of Vagal Nerve Stimulation on Cognition and Quality of Life in Epilepsy

To evaluate the cognitive and quality-of-life (QOL) impacts of vagal nerve stimulation (VNS), 160 patients with uncontrolled partial seizures from 20 sites were enrolled in a double-blind study. Patients were randomly assigned to low (minimal) stimulation (n = 82) or high (now clinically used) stimulation (n = 78) conditions and given a group of cognitive and QOL tests before implantation and after 12-16 weeks of VNS treatment. Results showed no clear cognitive changes. However, fewer emotional and physical problems were reported by the High Group than the Low Group at the end of the study. The 32 patients who had at least 50% seizure relief showed slightly more improvement in QOL variables than those patients who did not demonstrate this degree of seizure reduction. Overall, a small number of favorable QOL but no cognitive changes were associated with levels of VNS stimulation that are now typically used clinically.