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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Integrative Physiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1542791
This article is part of the Research Topic Enhancing Resilience in Military Personnel: Insights into Physiological, Physical, Psychological Dimensions View all 5 articles

Effects of cervical transcutaneous vagus nerve stimulation (ctVNS) on military cognitive performance during sleep deprivation

Provisionally accepted
Charelle Bottenheft Charelle Bottenheft 1*Yvonne Fonken Yvonne Fonken 2Lucia Hendrikse Lucia Hendrikse 1Matthijs Koedijk Matthijs Koedijk 1Annemarie Landman Annemarie Landman 1Olaf Binsch Olaf Binsch 1
  • 1 TNO Human Performance, Soesterberg, Netherlands
  • 2 TNO Learning & Workforce Development, Soesterberg, Netherlands

The final, formatted version of the article will be published soon.

    Maintaining cognitive performance during sleep deprivation is of vital importance in many professions, especially in high-risk professions like the military. It has long been known that sleep deprivation diminishes cognitive performance. To mitigate the negative effects on cognitive performance during crucial military tasks, new interventions are necessary. Non-invasive cervical transcutaneous vagus nerve stimulation (ctVNS) has gained traction as a method to boost alertness and cognitive functioning. We investigated the effects of a 2x2 minute ctVNS stimulation protocol on three cognitive tasks applied during conditions of sleep-deprivation: a psychomotor vigilance task (PVT), a multitasking task (SynWin), and an inhibitory control task (stop-signal task; SST). In addition, participants also performed a close-quarter-battle (CQB) test in virtual reality (VR) to examine if potential effects of ctVNS translate to operational military contexts. A total of 35 military operators from special operational forces (SOF) and SOF support units participated. They were randomly assigned to an active stimulation group or sham group. Before stimulation at 19:00h, participants performed baseline tests. Participants stayed awake through the night and performed the cognitive tasks every 3 hours. The last round of cognitive tasks was followed by the VR test. Though sleep deprivation was successfully induced, as evident from a decline in performance on all three cognitive tasks (effect of session: p < .001 SynWin; p < .001 PVT; p < .001 SST; Linear Mixed Model), no significant effects of ctVNS were found on cognitive task performance, as well as on the military operational VR task. However, the influence of stimulation intensity on SynWin performance showed a trend, indicating that higher stimulation intensities could have a negative impact on cognitive performance. A 2x2 minute stimulation protocol may not be sufficient to elicit beneficial effects on cognitive-and operational military performance. Moreover, correct stimulation intensity may be critical to induce effects on cognitive performance, as stimulation effects may follow an inverted-u dose-response curve. Stimulation intensities in the current study are higher compared to a similar study that reported beneficial effects of ctVNS, which may explain this null finding. Further research is recommended to optimize stimulation protocols and investigate robustness of effects.

    Keywords: Bottenheft, C / Fonken, Y.M., Hendrikse, L.F., Koedijk, M., Landman, A., &and Binsch, O vagus nerve stimulation, cervical transcutaneous vagus nerve stimulation, military cognitive performance, Sleep Deprivation, special operational forces

    Received: 10 Dec 2024; Accepted: 28 Jan 2025.

    Copyright: © 2025 Bottenheft, Fonken, Hendrikse, Koedijk, Landman and Binsch. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Charelle Bottenheft, TNO Human Performance, Soesterberg, Netherlands

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.