Researchers from the University of Colorado Boulder and Northwestern University have developed a tiny, soft, and wearable acoustic sensor that measures vibrations in the human body, allowing them to monitor human heart health and recognize spoken words. The stretchable device captures physiological sound signals from the body, has physical properties matched with human skin, and can be mounted on nearly any surface of the body. The sensor resembles a small Band-Aid®, weighs less than one-hundredth of an ounce, and can gather continuous physiological data.

The tiny, wearable acoustic sensor can be used to monitor heart health and recognize spoken words. (Northwestern University, University of Colorado Boulder)

The device picks 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 that include the opening and closing of heart valves, vibrations of the vocal cords, and movements in gastrointestinal tracts. The sensor can also integrate electrodes to record electrocardiogram (ECG) signals that measure the electrical activity of the heart, as well as 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 for use in remote, noisy places such as battlefields, or to produce quiet, high-quality cardiology or speech signals that can be read in real time at distant medical facilities.

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

The sticky, flexible polymer encapsulating the device is stretchable enough to follow skin deformation. The device contains a tiny commercial accelerometer to measure the vibration of body acoustics, and allows for the evaporation of human sweat. Vocal cord vibrations can be gathered when the device is on one's throat to control video games and other machines.

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NASA Tech Briefs Magazine

This article first appeared in the February, 2017 issue of NASA Tech Briefs Magazine.

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