Timing Considerations for Noninvasive Vagal Nerve Stimulation in Clinical Studies. Author: Gurel NZ1, Gazi AH1, Scott KL1, Wittbrodt MT2, Shah AJ3,4,5, Vaccarino V3,4, Bremner JD2,5,6, Inan OT1,7 Affiliation: <sup>1</sup>School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA. <sup>2</sup>Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA. <sup>3</sup>Department of Epidemiology, Rollins School of Public Health, Atlanta, GA. <sup>4</sup>Department of Internal Medicine, Emory University School of Medicine, Atlanta, GA. <sup>5</sup>Atlanta VA Medical Center, Decatur, GA. <sup>6</sup>Department of Radiology, Emory University School of Medicine, Atlanta, GA. <sup>7</sup>Coulter Department of Bioengineering, Georgia Institute of Technology, Atlanta, GA. Conference/Journal: AMIA Annu Symp Proc. Date published: 2020 Mar 4 Other: Volume ID: 2019 , Pages: 1061-1070 , Word Count: 143 Noninvasive vagal nerve stimulation (n-VNS) devices have the potential for widespread applicability in improving the well-being of patients with stress-related psychiatric disorders. n-VNS devices are known to affect physiological signals, and, recently, they have been employed in various protocols involving both acute and longitudinal applications. However, questions regarding response time, "dosage," or optimal treatment paradigms remain open. Prior work evaluated noninvasively obtained biomarkers that quantify the stimulation efficacy based on the changes in autonomic tone in a randomized double-blind study. In this work, we extend the state-of-the-art by investigating the onset of action for n-VNS in these same physiological biomarkers through a three-day clinical trial, including 233 administrations on 24 human participants, with and without immediately preceding acute traumatic stress. Determining n-VNS latency serves as a substantial step toward optimizing stimulation delivery with higher temporal resolution for personalized neuromodulation. ©2019 AMIA - All rights reserved. PMID: 32308903