What is the weight of medications changes along treatment with vagal nerve stimulation?

Vagus Nerve Stimulation (VNS) therapy has been widely recognized as an alternative for the treatment of drug resistant epilepsy (DRE), although modification of AEDs during VNS treatment could explain improvement in patients. We retrospectively assessed the efficacy of VNS in 30 adult epileptic patients treated with > 6 months follow-up. The criteria for implantation were the following: a) not candidate for resective epilepsy surgery, b) DRE, c) impairment of quality of life, d) no other option of treatment. We assessed socio-demographics, seizure etiology, seizure classification and AEDs used during treatment with VNS. We assessed adverse effects and efficacy. Responder rate was defined as >50 seizure improvement from baseline, Thirty patients (females-18, males-12; age 35.1+13.3) were included. After 6 months, 12 months, 24 months and 36 months, the response rate was as follows: 13/30(43%), 13/27 (48%), 9/22(41%) and 16/8 (50%), none of them were seizure free. Changes of AEDs were done in 57% of patients at 6 months, 43% at 12, 43% at 24, 43% at 24 months. Other outcomes will be discussed. Our study shows that VNS is an effective therapy although significant changes in medications were done along the therapy, therefore the real effect of VNS could be controversial