Brainstem Associated Somatosensory Evoked Potentials and Response to Vagus Nerve Stimulation: An Investigation of the Vagus Afferent Network

Abstract

Despite decades of clinical usage, selection of patients with drug resistant epilepsy who are most likely to benefit from vagus nerve stimulation (VNS) remains a challenge. The mechanism of action of VNS is dependent upon afferent brainstem circuitry, which comprises a critical component of the Vagus Afferent Network (VagAN). To evaluate the association between brainstem afferent circuitry and seizure response, we retrospectively collected intraoperative data from sub-cortical recordings of somatosensory evoked potentials (SSEP) in 7 children with focal drug resistant epilepsy who had failed epilepsy surgery and subsequently underwent VNS. Using multivariate linear regression, we demonstrate a robust negative association between SSEP amplitude (p < 0.01), and seizure reduction. There was no association between SSEP latency and seizure outcomes. Our findings provide novel insights into the mechanism of VNS and inform our understanding of the importance of brainstem afferent circuitry within the VagAN for seizure responsiveness following VNS.

Neurostimulation treatments for epilepsy: Deep brain stimulation, responsive neurostimulation and vagus nerve stimulation

“…Similarly, seizure characteristics, such as temporal region seizure onset, generalized epilepsy and tuberous sclerosis, are associated with greater response to VNS [ 28 , 36 , 37 ]. Connectomics studies have identified structural and functional connectivity patterns within the vagus afferent network that are associated with better outcomes to VNS treatment [ 20 , 25 , 38 ]. Electrical recordings, specifically the P300 component of scalp-recorded event-related potentials, have been shown to be distinct in patients who are considered to be responders to VNS and those deemed non-responders to treatment [ 39 ].…”