Objectives: Until now, the vagus nerve stimulation (VNS) treatment in epilepsy has consisted of two different modes: normal and magnet stimulation. A new vagus nerve stimulator model (106 AspireSR®, LivaNova, Houston, TX, USA) also allows automatic stimulation (AutoStim). The purpose of this study is to examine the effect of autostimulation on seizure frequencies together with energy consumption.
Materials and methods: The study material consisted of 14 patients whose former stimulator model (102/103) was replaced with model 106. We calculated the theoretical charge (Q) in Coulombs for one day in both of those groups. We evaluated the follow-up data of the patients' seizure counts, with a mean follow-up time of 18.1 months (SD 8.1).
Results: The total charge, "VNS dose," was reduced with model 106 in comparison with models 102 or 103 (p = 0.001, Mann-Whitney test). The average charge (Qtotal ) for one day with AutoStim was 142.56 mC; without AutoStim, it was 321.09 mC. We were able to assess seizure diaries in 11 out of 14 patients. Four patients (36%) had >50% seizure reduction and two patients (18%) experienced a reduction in seizure severity with VNS with autostimulation. Five patients (46%) remained unchanged. In three out of four patients with improved seizure control, the duty cycle was maintained at the original level. The patients whose duty cycle was modified for a more prolonged OFF-time had unchanged seizure frequencies.
Conclusion: VNS with AutoStim achieves maintenance of prior-established seizure control with markedly less energy consumption and can also improve seizure control as compared to former stimulator model.
Keywords: Autostimulation; epilepsy; neuromodulation; seizure; vagus nerve stimulation.
© 2018 International Neuromodulation Society.