Effects of Transcutaneous Vagus Nerve Stimulation on Cerebral Perfusion and Cognitive Function Under Simulated High-Altitude Hypobaric Hypoxia.

BACKGROUND

The aim of this study is to investigate the effects of hypobaric hypoxia (simulated altitude of 3600 m) on regional cerebral blood flow (CBF) and cognitive function, and to explore the regulatory role of transcutaneous vagus nerve stimulation (tVNS).

METHODS

Forty-three healthy Han Chinese males (18-45 years) were enrolled at the Chinese PLA General Hospital (June 2024-December 2025). During 24-h hypobaric hypoxia exposure via a specialized hypobaric chamber, participants were randomly assigned to tVNS (n = 23) or non-tVNS (n = 20) groups. A non-exposure cohort (n = 18) was included to correct for cognitive learning effects. Arterial spin labeling quantified CBF in the anterior, middle, and posterior cerebral artery territories and hippocampus at baseline, exposure, and post-exposure; the Repeatable Battery for the Assessment of Neuropsychological Status assessed cognitive function at the same time points.

RESULTS

Hypoxia-induced compensatory CBF increases across all examined regions in the control group (p < 0.05). In the tVNS group, CBF modulation was region-specific: frontotemporal CBF was higher at exposure than post-exposure and higher at post-exposure than baseline; occipital and hippocampal CBF were higher at exposure than at both other time points, with no difference between post-exposure and baseline. Only temporal lobe CBF was significantly higher in the tVNS group than the control group (76.22 ± 7.49 vs. 70.88 ± 8.93, p = 0.039). Hypoxia impaired visuospatial ability, language, and attention and delayed memory (all p < 0.05), but tVNS did not ameliorate these deficits.

CONCLUSIONS

Simulated 3600 m hypobaric hypoxia induces compensatory regional CBF elevations. tVNS selectively increases temporal lobe perfusion but does not ameliorate cognitive impairment, warranting optimized studies to clarify its neuroprotective role.