Acute Transcutaneous Cervical but not Auricular Vagus Nerve Stimulatio

Acute Transcutaneous Cervical but not Auricular Vagus Nerve Stimulation Increases Alpha Wave Brain Activity and Lowers Arterial Blood Pressure

Abstract:

Background:

Vagus nerve stimulation (VNS) has been associated with modulation of autonomic and stress-related physiological processes. Non-invasive VNS can be applied either to the cervical vagus nerve or to the auricular branch of the vagus nerve. Cervical stimulation may engage both afferent and efferent fibers, whereas auricular stimulation targets afferent pathways only. Whether these approaches differentially influence cardiovascular and cortical measures in healthy individuals remains incompletely characterized.

Methods:

Sixteen healthy young adults (5 males, 11 females) participated in study after providing informed consent. The study was approved by the Burrell College Institutional Review Board. Participants were randomly assigned to one of four groups: time control (no intervention), bilateral transcutaneous cervical VNS (cVNS), auricular VNS applied to the tragus (atVNS), or auricular VNS applied to the cymba conchae (acVNS). Following a 30-minute baseline recording, participants received either no intervention or three 5-minute stimulation periods separated by 1-minute rest intervals. Physiological measurements included ECG-derived heart rate, finger plethysmography–derived blood pressure, and single-channel frontal EEG (FP1).

Results:

Systolic blood pressure decreased during cVNS compared with baseline (133.6 ± 5.0 vs. 124.2 ± 4.8 mmHg, n = 7, P < 0.05), with no comparable changes observed in the control, atVNS, or acVNS groups. Heart rate did not change significantly in any group. Frontal EEG alpha wave amplitude showed an increase during cVNS that approached statistical significance (0.654 ± 0.070 vs. 0.827 ± 0.076 arbitrary units, n = 7, P = 0.06). No significant changes were detected in other EEG frequency bands.

Conclusions:

In this small cohort of healthy adults, bilateral transcutaneous cervical VNS was associated with lower systolic blood pressure and a trend toward increased frontal EEG alpha activity, whereas auricular VNS was not. These findings suggest that stimulation sites may influence physiological responses to non-invasive VNS. Further studies with larger samples and mechanistic endpoints are required to clarify the reproducibility, clinical relevance, and underlying pathways of these observations.

Authors:

Rodela Ahmed, Andrea Coello, Aamani S. Pillutla, Gurpret E.E. Telwar, and Harald M. Stauss Department of Biomedical Sciences, Burrell College of Osteopathic Medicine, Las Cruces, NM
Running Head
Transcutaneous Cervical vs. Auricular VNS
For Correspondence
Harald M. Stauss, MD, PhD
Burrell College of Osteopathic Medicine
Department of Biomedical Sciences
3501 Arrowhead Drive
Las Cruces, NM 88001
Phone: 575-674-2327
E-mail: hstauss@burrell.edu