title: Numerical modeling of percutaneous auricular vagus nerve stimulation: a realistic 3D model to evaluate sensitivity of neural activation to electrode position.
abstract: OBJECTIVE
  Percutaneous stimulation of the auricular branch of the vagus nerve (pVNS) by miniaturized needle electrodes in the auricle gained importance as a treatment for acute and chronic pain. The objective is to establish a realistic numerical model of pVNS and investigate the effects of stimulation waveform, electrodes' depth, and electrodes' position on nerve excitation threshold and the percentage of stimulated nerves.
  
  
  METHODS
  Simulations were performed with Sim4Life. An electrostatic solver and neural tissue models were combined for electromagnetic and neural simulation. The numerical model consisted of a realistic high-resolution model of a human ear, blood vessels, nerves, and three needle electrodes.
  
  
  RESULTS
  A novel 3D ear model was established, including blood vessels and nerves. The electric field distribution was extracted and evaluated. Maximum sensitivity to needles' depth and displacement was evaluated to be 9.8 and 15.5% per 0.1 mm, respectively. Stimulation was most effective using biphasic compared to mono-phasic pulses.
  
  
  CONCLUSIONS
  The established model allows easy and quantitative evaluation of various stimulation setups, enabling optimization of pVNS in experimental settings. Results suggest a high sensitivity of pVNS to the electrodes' position and depth, implying the need for precise electrode positioning. Validation of the model needs to be performed.
authors.affiliation: Department of Information Technology (INTEC), Ghent University/imec, iGent, Technologiepark-Zwijnaarde, 15, 9052, Ghent, Belgium. amine.samoudi@ugent.be.
authors.forename: Amine M
authors.initials: AM
authors.lastname: Samoudi
authors.affiliation: Research Group Biomedical Sensing, Institute of Electrodynamics, Microwave and Circuit Engineering, TU Wien, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kampusch
authors.affiliation: Department of Information Technology (INTEC), Ghent University/imec, iGent, Technologiepark-Zwijnaarde, 15, 9052, Ghent, Belgium.
authors.forename: Emmeric
authors.initials: E
authors.lastname: Tanghe
authors.affiliation: Department of Surgery, Medical University Vienna, Vienna, Austria.
authors.forename: Jozsef C
authors.initials: JC
authors.lastname: Széles
authors.affiliation: Department of Information Technology (INTEC), Ghent University/imec, iGent, Technologiepark-Zwijnaarde, 15, 9052, Ghent, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Martens
authors.affiliation: Research Group Biomedical Sensing, Institute of Electrodynamics, Microwave and Circuit Engineering, TU Wien, Vienna, Austria.
authors.forename: Eugenijus
authors.initials: E
authors.lastname: Kaniusas
authors.affiliation: Department of Information Technology (INTEC), Ghent University/imec, iGent, Technologiepark-Zwijnaarde, 15, 9052, Ghent, Belgium.
authors.forename: Wout
authors.initials: W
authors.lastname: Joseph
mesh_terms: D004558:Electric Stimulation / Q000379:methods; D004560:Electricity; D004566:Electrodes; D006801:Humans; D009716:Numerical Analysis, Computer-Assisted; D012680:Sensitivity and Specificity; D014630:Vagus Nerve / Q000502:physiology*; D055536:Vagus Nerve Stimulation / Q000379:methods
keywords: Auricular branch of the vagus nerve; Electromagnetic simulation; Neuromodulation; SENN