Effects of VNS stimulation on electrocorticography in patients with dual neuro- stimulation devices

Abstract

BackgroundOne-third of epilepsy patients become refractory to anti-epileptic medications. In these patients neurostimulation devices are considered as potential treatment options. The FDA has approved vagal nerve stimulation (VNS) and responsive neurostimulation (RNS system) for the treatment of focal epilepsy. There is limited data on interaction between the two devices and their mechanism of action is actively being researched. Limited prior evidence suggests that acute VNS stimulation may reduce epileptiform activity and cause EEG desynchronization. Our study aims to isolate the effects of VNS on electrocorticography (ECoG) as recorded by the RNS system.MethodsECoG from 20 patients were obtained. For each patient, five pairs of ‘on’ recordings of 60-second VNS stimulation on ECoGs were compared to ‘off’ baseline 60s recordings. ECoGs were analyzed for differences in spectral content.ResultsPreliminary results show that acute VNS stimulation is associated with significant decrease in power (i.e. desynchronization) in the theta, beta, and (50–70 Hz) gamma bands.ConclusionThis study demonstrates desynchronization as a mechanism of action of VNS, as recorded by the RNS system. As more patients receive dual neurostimulators, it will be crucial to understand isolated effects of each device to optimize programming and improve therapeutic efficacy.navya.joseph@unmc.edu