Vagus nerve stimulation has a positive effect on mood in patients with refractory epilepsy

Background: Preliminary research on the efficacy of vagus nerve stimulation (VNS) indicated additional effects on neuropsychological variables like mood and quality of life (QOL). Objectives: The objectives of this prospective longitudinal observational cohort study were to assess the effects of VNS on mood, QOL and cognition in patients with refractory epilepsy and to determine whether these effects occur dependent of seizure control. Methods: We included 41 patients with refractory epilepsy; treated with VNS as part of usual patient care. A neuropsychological battery was performed during baseline and repeated after 6 months of VNS in order to compare neuropsychological variables before and after VNS. All patients completed seizure diaries. Results: Significant improvements were observed for both mood and QOL after 6 months of VNS; based on the results in the POMS and QOLIE-89 questionnaires (p <0.05). There was no significant change in cognition. Mean percentage change in seizure frequency was -9.0%, while 20% of the patients achieved a seizure frequency reduction of 50% or more. No significant correlation was found between changes in seizure frequency and improvements in mood or QOL. Conclusions: VNS is associated with improvements in both mood and QOL in patients with refractory epilepsy. Since these improvements appeared to be independent of seizure control, the results of this study indicate an additional antidepressant effect of VNS, which can be of extra value in view of the high co-morbidity of mood disturbances in patients with epilepsy.