Wearable Focused Ultrasound Stimulation for Peripheral Nerve Pain Management

"This study uses a three-session cold pressor paradigm to evaluate feasibility of a wearable focused ultrasound (FUS) device for peripheral nerve stimulation.~Session 1 (Baseline): After consent, participants immerse the dominant hand in 0-1 °C water (\~10 cm depth) in an insulated bucket. Time to first pain is recorded, with 5 min rests between immersions (12 total; max single immersion 6 min). Water temperature is digitally monitored, with ice added as needed.~Session 2 (Sham): The median/ulnar/radial nerve in the dominant forearm is located by ultrasound. The FUS device is applied with hydrogel but set to sham (no output). The cold pressor protocol is repeated.~Session 3 (Active FUS): After nerve localization, active FUS (650 kHz, 60-100% intensity, 20-30% duty cycle) is delivered for 5 min. The cold pressor test is repeated to record pain tolerance as an exploratory physiological response during feasibility testing."

"This session records pressure pain thresholds in the dominant hand with a wearable FUS device and a pressure algometer during feasibility testing.~Session 1 (Baseline): After consent and briefing, the median, ulnar, and radial nerves at three points on the dominant hand (wrist, palm, finger) are located via ultrasound and marked. A pressure algometer is applied to each site, with pressure gradually increased until pain is first reported. Thresholds are recorded, with each location tested three times with short breaks.~Session 2 (Sham): The same nerve sites are identified and marked. The wearable FUS device is applied with hydrogel but set to sham (no active output). The baseline algometry protocol is repeated.~Session 3 (Active FUS): Following nerve localization, active FUS (650 kHz, 60-100% intensity, 20-30% duty cycle) is delivered for 5 min. The algometry test is repeated to record pressure pain thresholds as exploratory physiological responses during feasibility testing."

"This session records pressure pain thresholds in the dominant foot with a wearable FUS device and a pressure algometer during feasibility testing.~Session 1 (Baseline): After consent and briefing, the tibial, saphenous, and peroneal nerves at three standardized points on the dominant foot are located via ultrasound and marked. A pressure algometer is applied to each site, and pressure is gradually increased until pain is first reported. Thresholds are recorded, with repeated trials and short breaks between tests.~Session 2 (Sham): The same nerve sites are identified and marked. The wearable FUS device is applied with hydrogel but set to sham (no active output). The baseline algometry protocol is repeated.~Session 3 (Active FUS): Following nerve localization, active FUS (650 kHz, 60-100% intensity, 20-30% duty cycle) is delivered for 5 min. The algometry test is then repeated to record pressure pain thresholds as exploratory physiological responses during feasibility testing."