Engineers on the College of California San Diego have developed a wearable ultrasound machine 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 machine permits high-resolution monitoring of muscle operate with out invasive procedures.
A group of researchers led by Sheng Xu, a professor and Jacobs College Scholar within the Aiiso Yufeng Li Household Division of Chemical and Nano Engineering at UC San Diego, revealed their work Oct. 31 in Nature Electronics. The work was a collaborative challenge with Jinghong Li, a pulmonologist, intensive care specialist and professor of drugs at UC San Diego Well being.
In exams, the machine 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 expertise may doubtlessly 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 machine 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 recreation.
This wearable ultrasound expertise might supply a promising new different to the present medical commonplace, electromyography (EMG), which entails 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, supplies high-resolution imaging by penetrating deep tissues, providing detailed insights into muscle operate. The ultrasound expertise that Xu’s group and their collaborators developed has the extra benefits of being compact, wi-fi, and low-power. “This expertise may doubtlessly be worn by people throughout their day by 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 machine is housed in a versatile silicone elastomer casing and consists of three primary parts: a single transducer for sending and receiving ultrasound waves; a custom-designed wi-fi circuit that controls the transducer, information knowledge and wirelessly transmits the information to a pc; and a lithium-polymer battery that may energy the system for at the least three hours.
A key innovation of this work is the usage of a single ultrasound transducer to sense deep tissues successfully. The transducer emits intensity-controlled ultrasound waves and captures radiofrequency indicators that carry wealthy info, enabling medical purposes reminiscent of measuring diaphragm thickness. Utilizing these indicators, the machine can obtain excessive spatial decision, which is essential for isolating particular muscle actions. To extract further insights from these indicators, the researchers developed a man-made intelligence algorithm that maps the indicators to their corresponding muscle distributions, enabling it to establish particular hand gestures from the collected indicators with excessive accuracy and reliability.
When worn on the rib cage, the machine 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 totally different respiratory patterns, reminiscent of shallow and deep breaths. This performance may assist diagnose situations linked to respiratory irregularities, reminiscent of bronchial asthma, pneumonia and continual obstructive pulmonary illness (COPD). In a small group trial, the machine efficiently distinguished respiratory patterns of people with COPD from these of wholesome contributors.
“This demonstrates the expertise’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 machine presents exact monitoring of muscle movement within the arms and wrists. Due to the bogus intelligence algorithm that the group developed, the system is able to recognizing numerous hand gestures solely from the ultrasound indicators. The system is ready to acknowledge 13 levels of freedom, protecting 10 finger joints and three rotation angles of the wrist. Because of this, it will probably seize even slight wrist and finger actions with excessive sensitivity.
In proof-of-concept exams, contributors used the machine on their forearms to regulate a robotic arm to pipette water into beakers. In one other demonstration, they used the machine to play a digital recreation, utilizing wrist actions to regulate a digital chook’s flight by means of obstacles. “These demonstrations underscore the expertise’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 expertise’s accuracy, portability, power effectivity and computational capabilities.
