Tiny Wearable Auscultation Sensor Aims to be a Doctor’s Stethoscope for Every Home
Australian researchers have developed a lightweight wearable sensor that could continuously check on people with heart and breathing problems, potentially reducing hospital visits and allowing doctors to detect problems earlier.
The flexible sensor patch, which attaches to the chest or over peripheral arteries using medical adhesive tape, is designed to continuously capture subtle vibrations produced by the heart, lungs and, blood flow, and pulse waves.
Researchers hope the technology could eventually help people with chronic heart and respiratory conditions track their health remotely and alert clinicians when something may be wrong before symptoms become severe.
The proof-of-concept work, led by researchers from UNSW in collaboration with clinicians and biomedical engineers, has been published in Nature Communications.
Lead researcher and corresponding author of the paper, Scientia Associate Professor Hoang-Phuong Phan, says the goal is to create a wearable device which patients can use themselves – as a home alternative to the traditional doctor’s stethoscope.
“What we have developed is a tiny wearable device that can attach onto the human chest and hear heart sound and respiration,” A/Prof. Phan says.
“Technically, it aims to replace the stethoscope, which is normally used in clinic centres to assess cardiovascular or respiration disease.”
Addressing a growing healthcare challenge
Heart disease and chronic respiratory illnesses remain among the leading causes of death worldwide, but many patients only receive brief assessments during occasional medical appointments. A/Prof. Phan says this can create major challenges for people living in regional and remote areas, or patients reluctant to repeatedly visit hospitals and clinics.
“Normally, when patients are assessed by a doctor, they have to go to a clinic centre, and it’s not very convenient for those who live in remote areas,” he says. “Sometimes people are hesitant to go to hospital, so they wait until symptoms are clearly developed.”
By the time symptoms become serious enough to seek medical care, diseases may already have significantly worsened.
“At that stage, the disease may already have worsened, leaving poorer outcomes for patients even when treated,” says Dr Anthony Sunjaya, a medical doctor and Program Lead for Chronic Respiratory Disease at UNSW’s School of Population Health, who co-authored in this work. “When they go to a clinic, patients often only have a 15-minute window for assessment. The danger is that the abnormalities experienced will not be fully recognised during that short period of time they are being seen.”
How the patch works
The device, known as ‘AusculPatch’, is smaller and lighter than many existing wearable monitoring systems, weighing only 3.2 grams and measuring roughly 20x47x3 millimetres. At the centre of the patch is an ultra-thin silicon sensing element that detects tiny mechanical vibrations travelling through the skin from the heart, lungs and blood vessels.
“The heart sound propagates through the body fluid and tissue generates an acoustic pressure that vibrates the sensing element,” Tran Bach Dang, the first author and a PhD candidate from the School of Mechanical and Manufacturing Engineering says. “What the patch is doing is picking up that vibration.”
The new sensor can detect extremely low-frequency vibrations that are difficult to capture with current wearable technology. The device can detect a remarkably broad range of physiological signals, including breathing patterns, pulse waves, heart sounds and blood flow vibrations.
In tests, the AusculPatch was able to continously monitor a range of physiological markers while the wearer was undertaking regular daily tasks. Importantly, researchers say the patch was designed to minimise interference from surrounding environmental noise — a major challenge for wearable acoustic sensors.
“The sensor element is designed to shield the sound coming from one direction, typically from the human body,” Dang says. “In that way, it is less susceptible to ambient sound.”
Although tested on only a small number of healthy participants, the research paper showed the device could continue capturing clear heart sounds even in noisy environments, including during conversation and under simulated background noise conditions.
Beyond smartwatches and fitness trackers
While consumer devices such as smartwatches and sleep trackers can already monitor heart rate and blood oxygen levels, the research team says AusculPatch captures more direct mechanical information about how the heart and lungs are functioning.
The researchers believe the technology could eventually have applications ranging from chronic disease management to sleep monitoring and general wellbeing.
The paper also highlights potential use in monitoring blood pressure, pulse waves and subtle heart valve abnormalities that are difficult to continuously track outside hospital settings.
In laboratory and early human testing, the device showed strong agreement with clinical tools including electrocardiograms (ECGs), ultrasound scans, blood pressure monitors and digital stethoscopes.
Researchers were also able to continuously record cardiorespiratory data over extended periods while participants walked, worked, ate meals and climbed stairs.
AI-powered monitoring
One of the most promising aspects of the technology is the possibility of combining continuous monitoring with artificial intelligence.
Because the patch collects large amounts of physiological data over time, researchers hope machine learning systems could eventually identify patterns linked to worsening disease or emerging health problems.
“We can potentially apply machine learning to identify abnormal signal and warn the patients, and also notify their doctor,” Dr. Chi Cong Nguyen, an Associate Lecturer and a corresponding author of the paper says.
“The goal is to create a system that can automatically flag concerning changes before patients experience severe symptoms.”
Potential future applications
Beyond cardiorespiratory monitoring, the researchers also demonstrated that the patch could detect vocal cord vibrations from the throat. In proof-of-concept experiments, the team used machine learning to recognise spoken words and wirelessly control a robotic arm. While those experiments are still early-stage, the researchers say the technology could eventually support people with speech disorders or physical disabilities.
Although the technology is still in the research and testing phase, larger clinical studies are already being planned.
The team, which also includes Associate Professor Thanh Nho Do, Scientia Professor Nigel Lovell, and Professor Tracie Barber, as well as external partners, hopes to begin testing the device on around 200 patients this year.
That group is expected to include people with heart valve disease or implanted heart assist devices. Researchers then hope to scale up studies to around 1000 patients over the following years to further develop AI-assisted diagnostic tools. Regulatory approval for a medical-grade device would still take time, with A/Prof. Phan estimating a timeline of around four to five years before possible clinical deployment. However, consumer-focused wellness versions of the technology could potentially become available sooner.
Source: University of New South Wales
