TEMPO-taVNS: a multimodal platform optimizing thermal, electrical, and mechanical auricular stimulation

Transcutaneous auricular vagus nerve stimulation (taVNS) is typically delivered electrically, while alternative stimulation modalities and their potential for personalization remain underexplored. We present TEMPO-taVNS (Thermal, Electrical, and Mechanical Parameter Optimization for taVNS), a human-centered methodology for multimodal auricular neuromodulation designed to explore and optimize stimulation of sensory pathways associated with the auricular branch of the vagus nerve (ABVN). The platform integrates custom hardware capable of delivering thermal, vibrotactile, and electrical stimulation with software that enables systematic parameter sweeps. Responses are characterized through high-resolution physiological monitoring including heart rate, heart rate variability, gastric slow-wave activity, pupil diameter, beat-to-beat blood pressure, brain response activity, and electrodermal activity, together with participant-reported perception and comfort. To address interindividual variability, a Pareto-front Gaussian-process optimization framework identifies personalized stimulation parameters by balancing physiological response with user comfort. We further describe experimental protocols for evaluating this multimodal parameter space in humans. Together, the hardware, software, physiological sensing, and optimization framework provide a scalable foundation for individualized, non-invasive and nonpharmacological auricular neuromodulation, and for investigating non-electrical approaches to vagal stimulation for wearable neuromodulation systems.