Engineers on the College of California San Diego have developed a wearable ultrasound system that may present long-term, wi-fi monitoring of muscle exercise with potential purposes in healthcare and human-machine interfaces. Designed to stay to the pores and skin with a layer of adhesive and powered by a battery, the system permits high-resolution monitoring of muscle operate with out invasive procedures.
A crew of researchers led by Sheng Xu, a professor and Jacobs School Scholar within the Aiiso Yufeng Li Household Division of Chemical and Nano Engineering at UC San Diego, printed their work Oct. 31 in Nature Electronics. The work was a collaborative undertaking with Jinghong Li, a pulmonologist, intensive care specialist and professor of drugs at UC San Diego Well being.
In exams, the system was worn over the rib cage to observe diaphragm movement and thickness, that are helpful for assessing respiratory well being. “By monitoring diaphragm exercise, the know-how may probably assist sufferers with respiratory situations and people reliant on mechanical air flow,” mentioned Joseph Wang, a distinguished professor within the Aiiso Yufeng Li Household Division of Chemical and Nano Engineering who’s a co-author on the examine.
Moreover, researchers efficiently used the system on the forearm to seize hand and wrist muscle exercise, which enabled its use as a human-machine interface to regulate a robotic arm and play a digital sport.
This wearable ultrasound know-how might supply a promising new different to the present medical commonplace, electromyography (EMG), which includes making use of metallic electrodes on the pores and skin to file electrical muscle exercise. Regardless of EMG’s longstanding use, it suffers from low decision and weak indicators. For instance, indicators from a number of muscle fibers usually mix collectively, making it difficult to isolate the contributions of particular muscle fibers.
Ultrasound, nonetheless, offers high-resolution imaging by penetrating deep tissues, providing detailed insights into muscle operate. The ultrasound know-how that Xu’s crew and their collaborators developed has the extra benefits of being compact, wi-fi, and low-power. “This know-how may probably be worn by people throughout their each day routines for steady, long-term monitoring,” mentioned examine co-first writer Xiangjun Chen, a Ph.D candidate within the Supplies Science and Engineering program at UC San Diego.
The system is housed in a versatile silicone elastomer casing and consists of three fundamental parts: a single transducer for sending and receiving ultrasound waves; a custom-designed wi-fi circuit that controls the transducer, data information and wirelessly transmits the information to a pc; and a lithium-polymer battery that may energy the system for at the very least three hours.
A key innovation of this work is using a single ultrasound transducer to sense deep tissues successfully. The transducer emits intensity-controlled ultrasound waves and captures radiofrequency indicators that carry wealthy data, enabling medical purposes comparable to measuring diaphragm thickness. Utilizing these indicators, the system can obtain excessive spatial decision, which is vital for isolating particular muscle actions. To extract extra insights from these indicators, the researchers developed a man-made intelligence algorithm that maps the indicators to their corresponding muscle distributions, enabling it to determine particular hand gestures from the collected indicators with excessive accuracy and reliability.
When worn on the rib cage, the system can precisely monitor diaphragm thickness with submillimeter precision. Diaphragm thickness is a metric used within the clinic to guage diaphragm dysfunction and predict outcomes in ventilated sufferers. By analyzing muscle movement, the researchers may additionally detect completely different respiratory patterns, comparable to shallow and deep breaths. This performance may assist diagnose situations linked to respiratory irregularities, comparable to bronchial asthma, pneumonia and persistent obstructive pulmonary illness (COPD). In a small group trial, the system efficiently distinguished respiratory patterns of people with COPD from these of wholesome individuals.
“This demonstrates the know-how’s potential for medical purposes in respiratory care,” mentioned examine co-first writer Muyang Lin, a postdoctoral researcher within the Aiiso Yufeng Li Household Division of Chemical and Nano Engineering at UC San Diego.
When worn on the forearm, the system gives exact monitoring of muscle movement within the fingers and wrists. Because of the synthetic intelligence algorithm that the crew developed, the system is able to recognizing varied hand gestures solely from the ultrasound indicators. The system is ready to acknowledge 13 levels of freedom, masking 10 finger joints and three rotation angles of the wrist. In consequence, it could possibly seize even slight wrist and finger actions with excessive sensitivity.
In proof-of-concept exams, individuals used the system on their forearms to regulate a robotic arm to pipette water into beakers. In one other demonstration, they used the system to play a digital sport, utilizing wrist actions to regulate a digital fowl’s flight by obstacles. “These demonstrations underscore the know-how’s potential for prosthetics, gaming and different human-machine interface purposes,” mentioned examine co-first writer Wentong Yue, a Ph.D. candidate within the Aiiso Yufeng Li Household Division of Chemical and Nano Engineering at UC San Diego.
Shifting ahead, the researchers plan to enhance the know-how’s accuracy, portability, vitality effectivity and computational capabilities.
