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

Hrishikesh Suresh; Karim Mithani; Karanbir Brar; Han Yan; Samuel Strantzas; Mike Vandenberk; Roy Sharma; Ivanna Yau; Christina Go; Elizabeth Pang; Elizabeth Kerr; Ayako Ochi; Hiroshi Otsubo; Puneet Jain; Elizabeth Donner; O Carter Snead; George M Ibrahim

doi:10.3389/fneur.2021.768539

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

Front Neurol. 2022 Feb 18:12:768539. doi: 10.3389/fneur.2021.768539. eCollection 2021.

Authors

Hrishikesh Suresh^{1

2

3}, Karim Mithani^{1

3}, Karanbir Brar⁴, Han Yan^{2

3

5}, Samuel Strantzas³, Mike Vandenberk³, Roy Sharma⁶, Ivanna Yau⁶, Christina Go⁶, Elizabeth Pang^{2

6}, Elizabeth Kerr^{6

7}, Ayako Ochi⁶, Hiroshi Otsubo⁶, Puneet Jain⁶, Elizabeth Donner⁶, O Carter Snead^{2

6

8}, George M Ibrahim^{1

2

3

8}

Affiliations

¹ Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
² Program in Neuroscience and Mental Health, The Hospital for Sick Children Research Institute, Toronto, ON, Canada.
³ Division of Neurosurgery, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
⁴ Division of General Surgery, Department of Surgery, University of Toronto, Toronto, ON, Canada.
⁵ Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada.
⁶ Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
⁷ Department of Psychology, The Hospital for Sick Children, Toronto, ON, Canada.
⁸ Institute of Medical Science, University of Toronto, Toronto, ON, Canada.

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.

Keywords: epilepsy; outcomes; somatosensory evoked potentials; vagus afferent network; vagus nerve stimulation.