A tiny wearable acoustic sensor that measures physiological vibrations has been developed by researchers from the University of Colorado Boulder and the Northwestern University, providing them with the ability to monitor the heart and even recognise spoken words.
The device was announced in a paper published in Science Advances, a sister journal of Science. The paper was authored by Assistant Professor at CU Boulder, Jae-Woong Jeong, Professor of Engineering at Northwestern University, Yonggang Huang, and Simpson Querrey Professor of Materials Science and Engineering, Biomedical Engineering and Medicine at Northwestern University John Rogers. The paper was also co-authored by CU Boulder Assistant Professor Jianliang Xiao, doctoral student of mechanical engineering, Zhanan Zou, and doctoral student of electrical engineering, Raza Qazi.
The sensor, which resembles a small Band-Aid and weighs less than 30 grams, captures continuous physiological sound data from the body using a tiny commercial accelerometer.
Additionally, the device has similar physical properties to human skin, allowing it to be comfortably worn almost anywhere on the human body while allowing for the evaporation of human sweat.
“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.
“It is very comfortable and convenient, you can think of it as a tiny, wearable stethoscope,” Continued Jeong.
The researchers state that the device is able to pick up vibrations that propagate through tissues and fluids in the human body, and is able to collect acoustic information in enough detail to differentiate between characteristic events within the body.
“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,” said Rogers.
The sensor is also able to integrate electrodes that record electrocardiogram (ECG) signals of the heart and electromyogram (EMG) signals from muscles.
According to Jeong, the sensor can easily be converted into a wireless device from its original wired external data acquisition system. He believes that such sensors could be useful in remote, noisy locations to produce high-quality cardiology or speech signals that can be read in real time at distant medical facilities.
“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,” said Jeong.
The speech recognition capabilities of the sensor also have implications for improving communication for people suffering from speech impairments, he added.
Part of the study included measuring the cardiac acoustic responses and ECG activity of a group of elderly volunteers at private medical clinic Camp Lowell Cardiology in Tucson, Arizona, in collaboration with the University of Arizona. The device was even able to detect blood clots, according to Jeong.
The researchers also showed that the device could be used to control video games and other machines, using vocal cord vibrations recorded by a device placed on the throat. By giving vocal commands, a test volunteer was able to control a game of Pac-Man by stating words such as “up,” “down,” “left” and “right.”
“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,” said Jeong.
“Our goal is to make this device practical enough to use in our daily lives,” concluded Jeong.