Wearable electronic device monitors heart and recognizes speech

A tiny, soft wearable acoustic sensor has been developed to measure vibrations in the human body, allowing them to monitor human heart health and recognize spoken words.

The researchers from the University of Colorado Boulder and Northwestern University designed the device to capture physiological sound signals from the body.

This stretchable monitor has physical properties well-matched with human skin so it can be mounted on nearly any surface of the body.

CU Boulder Assistant Professor Jae-Woong Jeong, one of three lead study authors said the sensor, which resembles a small Band-Aid, weighs less than one-hundredth of an ounce and can gather continuous physiological data.

“This device has a very low mass density and can be used for cardiovascular monitoring, speech recognition and human-machine interfaces in daily life,” said Jeong of the Department of Electrical, Computer and Energy Engineering.

He added: “It is very comfortable and convenient – you can think of it as a tiny, wearable stethoscope.”

Rogers, Director of Northwestern’s Center for Bio-Integrated Electronics, said: “The thin, soft, skin-like characteristics of these advanced wearable devices provide unique capabilities for ‘listening in’ to the intrinsic sounds of vital organs of the body, including the lungs and heart, with important consequences in continuous monitoring of physiological health.”

The new device can pick up mechanical waves that propagate through tissues and fluids in the human body due to natural physiological activity, revealing characteristic acoustical signatures of individual events. They include the opening and closing of heart valves, vibrations of the vocal cords and even movements in gastrointestinal tracts.

The sensor can also integrate electrodes that can record electrocardiogram (ECG) signals that measure the electrical activity of the heart as well electromyogram (EMG) signals that measure the electrical activity of muscles at rest and during contraction.

While the sensor was wired to an external data acquisition system for the tests, it can easily be converted into a wireless device, said Jeong. Such sensors could be of use in remote, noisy places – including battlefields – producing quiet, high-quality cardiology or speech signals that can be read in real time at distant medical facilities.

Jeong said: “Using the data from these sensors, a doctor at a hospital far away from a patient would be able to make a fast, accurate diagnosis.”

Vocal cord vibration signals also could be used by the military personnel or civilians to control robots, vehicles or drones. The speech recognition capabilities of the sensor also have implications for improving communication for people suffering from speech impairments.

As part of the study, the team used the device to measure cardiac acoustic responses and ECG activity -including the detection of heart murmurs – in a group of elderly volunteers at Camp Lowell Cardiology, a private medical clinic in Tucson, Arizona collaborating with the University of Arizona, a project partner. The researchers also were able to detect the acoustical signals of blood clots in a related lab experiment.

“The sticky, flexible polymer encapsulating the tiny device is stretchable enough to follow skin deformation,” said study’s first author Yuhao Liu.

The device contains a tiny commercial accelerometer to measure the vibration of the body acoustics and allows for the evaporation of human sweat.

The researchers also showed vocal cord vibrations gathered when the device is on one’s throat can be used to control video games and other machines. As part of the study a test subject was able to control a Pac-Man game using vocal cord vibrations for the words ‘up,’ ‘down,’ ‘left’ and ‘right’.

Jeong added: “While other skin electronics devices have been developed by researchers, what has not been demonstrated before is the mechanical-acoustic coupling of our device to the body through the skin. Our goal is to make this device practical enough to use in our daily lives.”

More information: TechXplore.