Post-stroke Pain taVNS

In this study, investigators main goal is to establish transcutaneous auricular vagus nerve stimulation (taVNS) as an effective non-invasive neuromodulation method for analgesia of post-stroke upper extremity pain. Participants are required to have an ischemic or hemorrhagic stroke that occurred at least 6 months prior and are currently suffering upper extremity pain. Each participant will undergo an in-person visit. Participants will first finish the pain questionnaires and have quantitative sensory testing (QST) conducted to determine baseline pain thresholds. Participants will then receive 30 minutes of taVNS (either active or sham). Upon the completion of the stimulation intervention, participants will then be tested for another QST and pain questionnaires.

Aim 1: Test the safety and feasibility of taVNS in participants with chronic post-stroke upper extremity pain.

Over the last 8 years, investigators have demonstrated that taVNS is safe and feasible in several different populations in our previous studies. Specifically, investigators have demonstrated that taVNS is well tolerated and safe for participants with chronic stroke in our previous clinical trial. In this study, investigators will further verify the safety and feasibility of taVNS in the population with chronic post-stroke upper extremity pain.

Aim 2: Investigate whether taVNS can modulate pain in this population compared to sham.

In this single-visit, double-blinded, sham-controlled pilot trial, investigators will compare changes in post-stroke upper extremity pain scores and pain threshold derived from QST before and after a 30-minute taVNS intervention, as well as between active and sham taVNS. The findings will help investigators understand whether taVNS can modulate pain in this population.