Wearable Focused Ultrasound Stimulation for Peripheral Nerve Pain Management

Focused Ultrasound Stimulation of Peripheral Nerves in Limbs

This study will evaluate the feasibility of a novel wearable focused ultrasound (FUS) device for peripheral nerve stimulation in healthy volunteers. The aim is to assess device operability, usability, tolerability, and physiological responses during standardized sensory tests. Each participant will complete nine ~1-hour study sessions across multiple days, including cold pressor and algometry tasks performed under baseline, sham, and active FUS conditions.

This feasibility study will evaluate a wearable focused ultrasound (FUS) system designed for non-invasive peripheral nerve stimulation of upper and lower extremity nerves. The primary objective is to determine device feasibility - operability, tolerability, usability, and physiological responses - during standardized pain sensitivity tasks.

Each participant will complete nine sessions on separate days (~1 hour each) in a within-subject crossover design:

1. Cold pressor test (baseline, sham, active FUS) - 3 days
2. Upper limb algometry (baseline, sham, active FUS) - 3 days
3. Lower limb algometry (baseline, sham, active FUS) - 3 days

Sessions will be scheduled at least 24 hours apart to avoid carryover effects. Approximately 12-15 participants will be enrolled. Although feasibility studies often include fewer than 10 participants, this sample size was chosen to ensure variability across limb anatomy and usability testing. No efficacy hypotheses or clinical outcomes will be tested.

Inclusion Criteria:

- Healthy adults aged 20-40, willing and able to undergo FUS experiments.

Exclusion Criteria:

• Major physical illnesses.
• Diagnosis of a cognitive disorder.
• Cardiovascular conditions (e.g., high blood pressure, heart disease, or dysrhythmia), history of fainting or seizures, or history of frostbite.
• Open cuts, sores, or bone fractures on the limb to be immersed in water, or a history of Raynaud's phenomenon.
• Diagnosis of hypersensitivity or hyposensitivity to bodily sensations (temperature, vibrotactile, nociception).
• Inability to provide informed consent for FUS stimulation.