Moving beyond belief: A narrative review of potential biomarkers for transcutaneous vagus nerve stimulation.

Author: Burger AM1,2, D'Agostini M1, Verkuil B3, Van Diest I1
Author Information:
1Health Psychology Research Group, Faculty of Psychology and Educational Sciences, University of Leuven, Leuven, Belgium.
2Biological Psychology Research Group, Faculty of Psychology and Educational Sciences, University of Leuven, Leuven, Belgium.
3Department of Clinical Psychology, Leiden University, Leiden, the Netherlands.
Conference/Journal: Psychophysiology.
Date published: 2020 Mar 23
Other: Volume ID: e13571 , Special Notes: doi: 10.1111/psyp.13571. [Epub ahead of print] , Word Count: 193


Transcutaneous vagus nerve stimulation (tVNS) is a non-invasive neurostimulation technique that is currently being tested as a potential treatment for a myriad of neurological and psychiatric disorders. However, the working mechanisms underlying tVNS are poorly understood and it remains unclear whether stimulation activates the vagus nerve for every participant. Finding a biological marker of tVNS is imperative, as it can help guide research on clinical applications and can inform researchers on optimal stimulation sites and parameters to further optimize treatment efficacy. In this narrative review, we discuss five potential biomarkers for tVNS and review currently available evidence for these markers for both invasive and tVNS. While some of these biomarkers hold promise from a theoretical perspective, none of the potential biomarkers provide clear and definitive indications that tVNS increases the vagal activity or augments activity in the locus coeruleus-noradrenaline network. We conclude the review by providing several recommendations for how to tackle the challenges and opportunities when researching potential biomarkers for the effects of tVNS.

© 2020 Society for Psychophysiological Research.

KEYWORDS: P300; biomarker; heart rate variability; locus coeruleus; noradrenaline; pupil size; salivary alpha-amylase; transcutaneous vagus nerve stimulation; vagal somatosensory evoked potential

PMID: 32202671 DOI: 10.1111/psyp.13571

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