New York, Nov 17 (IANS) US researchers, led by one of Indian origin, have developed world's first new soft, miniaturised wearable devices that can continuously track subtle sounds in the human body and provide valuable information about a person's health.

The device can track the sounds -- air moving in and out of the lungs, heart beats and even digested food progressing through the long gastrointestinal tract -- simultaneously and wirelessly at multiple locations across nearly any region of the body.

In pilot studies, Northwestern University researchers in the US tested the devices on 15 premature babies with respiratory and intestinal motility disorders and 55 adults, including 20 with chronic lung diseases.

Not only did the devices perform with clinical-grade accuracy, they also offered new functionalities that have not been developed nor introduced into research or clinical care, revealed the study published in the journal Nature Medicine.

"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 Ankit Bharat, a thoracic surgeon at Northwestern Medicine, who led the clinical research in the adult subjects.

Containing pairs of high-performance, digital microphones and accelerometers, the small, lightweight devices gently adhere to the skin to create a comprehensive non-invasive sensing network.

By simultaneously capturing sounds and correlating those sounds to body processes, the devices spatially map how air flows into, through and out of the lungs as well as how cardiac rhythm changes in varied resting and active states, and how food, gas and fluids move through the intestines.

Encapsulated in soft silicone, each device measures 40 millimetres long, 20 millimetres wide and 8 millimetres thick. Within that small footprint, the device contains a flash memory drive, tiny battery, electronic components, Bluetooth capabilities and two tiny microphones -- one facing inward toward the body and another facing outward toward the exterior.

By capturing sounds in both directions, an algorithm can separate external (ambient or neighbouring organ) sounds and internal body sounds.

The device was particularly helpful for premature babies in the neonatal intensive care unit (NICU). Premature babies commonly suffer from apnoeas, which are also a leading cause of prolonged hospitalisation and potentially death.

"Many of these babies are smaller than a stethoscope, so they are already technically challenging to monitor," said Dr. Debra E. Weese-Mayer, a co-author, chief of autonomic medicine at Ann & Robert H. Lurie Children's Hospital of Chicago.

"The beauty of these new acoustic devices is they can non-invasively monitor a baby continuously -- during wakefulness and sleep -- without disturbing them," Weese-Mayer added.

In adults with chronic lung diseases and healthy controls, the devices captured the distribution of lung sounds and body motions at various locations simultaneously, enabling researchers to analyse a single breath across a range of regions throughout the lungs.