Determine whether gel-free flexible electrodes are suitable for longitudinal tcVNS

Determine whether gel-free, flexible electrodes can provide sufficient comfort and contact quality for longitudinal transcutaneous cervical vagus nerve stimulation deployment studies.

Background

The study used a handheld, FDA-cleared stimulator with electrode gel, but a practical wearable implementation would require electrodes that maintain reliable electrical contact during extended use. The authors identify electrode design as unresolved because gel may require periodic replacement and because reliable contact is particularly important for vagus nerve stimulation. They specifically leave open whether gel-free, flexible electrodes can simultaneously provide adequate comfort and contact quality in longitudinal deployments.

References

A key unresolved problem is electrode design. Recent HCI work on electrical muscle stimulation and electrical nerve stimulation has integrated stimulation electrodes into wearables such as smartwatches, sleeves, and nose rings. Knibbe et al., for example, used conductive fabric electrodes that could be built into a flexible form factor, but still required gel, which often needs periodic replacement. Recent smart-textile work has explored carbon-based dry electrodes integrated into fabric to address this issue. For VNS, reliable electrical contact is particularly important: some participants initially reported tingling discomfort, which was resolved after adding more electrode gel. Future work should investigate whether gel-free, flexible electrodes can provide sufficient comfort and contact quality for longitudinal tcVNS deployment studies.

— AppetiteCheck: Feasibility of Momentary Vagus Nerve Stimulation as an Implicit Intervention for Eating Behavior  (2609.09700 - Gemicioglu et al., 9 Sep 2026) in Section “Towards Closed-Loop, Wearable tcVNS,” subsection “Device and Electrode Design”