Miniaturized Wearables Capture Body Sounds to Continuously Monitor Health

Physicians have long relied on the sounds within patients’ bodies — such as breaths, heartbeats, and gastrointestinal movements — to gauge health during routine check-ups. These internal sounds are key indicators of well-being, and any alterations or cessation can indicate critical health issues requiring prompt attention. In a significant advancement, researchers are now developing novel, soft wearable devices that enhance monitoring by continuously tracking these internal sounds. Unlike traditional assessments carried out occasionally during doctor visits, these new devices offer continuous, wireless monitoring across various body regions.

Developed by a team at Northwestern University in Evanston, IL, USA, these compact and lightweight devices softly attach to the skin, forming an innovative, non-intrusive sensing network. The devices contain pairs of high-quality digital microphones and accelerometers, enabling them to capture and analyze sounds to map bodily processes. These processes include the flow of air in and out of the lungs, the rhythms of the heart under different conditions, and the movement of contents through the gastrointestinal tract.

Image: The first-of-their-kind wearables were tested on a range of patients, from premature babies to the elderly (Photo courtesy of Northwestern University)

Each device, encased in soft silicone, is small in size — measuring 40 millimeters in length, 20 millimeters in width, and 8 millimeters in thickness. Despite its compact size, it is equipped with essential features including flash memory, a miniature battery, electronic components for processing, Bluetooth connectivity, and dual microphones — one directed inward towards the body and the other outward. This dual-microphone setup allows for the distinction between internal body sounds and external noises, including ambient sounds and those from adjacent organs. The ambient noise capturing not only facilitates noise cancellation but also gathers valuable information about the patient's environment, crucial in scenarios like treating premature infants.

The primary focus of these devices has been on two particularly vulnerable patient groups: premature infants in neonatal intensive care units (NICU) and adults recovering post-surgery. During initial tests involving 15 premature infants with respiratory and gastrointestinal issues and 55 adults, including 20 with chronic lung conditions, the devices demonstrated clinical-grade accuracy and introduced new capabilities previously unseen in research or clinical settings. Besides providing continuous monitoring, these devices also free NICU infants from the multitude of sensors, wires, and cables usually connected to bedside monitors.

“The idea behind these devices is to provide highly accurate, continuous evaluation of patient health and then make clinical decisions in the clinics or when patients are admitted to the hospital or attached to ventilators,” said Dr. Ankit Bharat, a thoracic surgeon at Northwestern Medicine, who led the clinical research in the adult subjects. “A key advantage of this device is to be able to simultaneously listen and compare different regions of the lungs. Simply put, it’s like up to 13 highly trained doctors listening to different regions of the lungs simultaneously with their stethoscopes, and their minds are synced to create a continuous and a dynamic assessment of the lung health that is translated into a movie on a real-life computer screen.”

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