Fully Wearable Armband for Long-Term Peripheral Ultrasound Neuromodulation in Pain Management

Chronic pain is a leading cause of medical consultations, often managed with opioids despite their high risk of addiction. Low-Intensity Focused Ultrasound (LIFU) neuromodulation has emerged as a promising non- invasive alternative for pain management. However, effective pain modulation often requires prolonged or continuous stimulation, and current LIFU devices are typically bulky and tethered to external power sources, limiting their applicability as wearable technologies for long-term use. This study introduces a fully wearable LIFU-based armband designed for peripheral nerve stimulation in pain management. It integrates a concave piezoelectric transducer, an acoustic hydrogel sheet for strong adhesion and extended use, as well as a miniaturized electronic circuit with a lithium-ion battery in a fabric armband for comfortable placement. LIFU was applied to the median nerve, and its effects on pain thresholds were evaluated in healthy volunteers using pressure algometry and cold pressor tasks. Results showed a significant increase in pain thresholds, with an average rise of 15%. These findings support the potential of wearable LIFU neuromodulation as a noninvasive and portable therapy for chronic pain management.