Quality of life and memory after vagus nerve stimulator implantation for epilepsy

Objective: This prospective, case control study evaluates quality of life (QOL), depressive affect, and memory outcomes of epilepsy patients implanted with a vagus nerve stimulator (VNS). Methods: Three groups of patients with epilepsy underwent assessment on two occasions: 1) patients with a VNS were tested before and 12 months after implantation (n = 16); 2) patients who underwent cerebral resective surgery were tested pre- and post-operatively (n = 10); and 3) patients under medical management (n = 9). Group means were compared on the QOLIE-89, Geriatric Depression Scale, Wechsler Memory Scale - III, and the Memory Observation Questionnaire. Secondary analyses calculated the reliable change index, providing information on change beyond measurement error and chance. Results: Mean ratings of QOL, depression, and memory complaints and objective memory scores remained stable or improved in all the groups. The QOL improved more after cerebral resective surgery than VNS or medication controls, but the VNS and medication control groups did not differ. In the VNS group, QOL was not related to seizure reduction. The percentage of cases showing real change in memory was equivalent across groups, except in one of eight indices (i.e., verbal recognition memory). Conclusions: This first case controlled design found that vagus nerve stimulation as an adjunctive therapy for seizure control did not change QOL, depressive affect, or objective memory scores over one-year more so than medical management alone. We point out the need for larger case control, non-industry funded investigations.