Researchers have developed an integrated, wearable device system that monitors a user’s environment, heart rate and other physical attributes to predict and prevent asthma attacks
Photo credit: NC State University
The system, called the Health and Environmental Tracker (HET), incorporates sensing devices into a wristband and a patch that adheres to the chest.
Photo credit: James Dieffenderfer
A prototype of the HET chest patch
The patch includes sensors that track a patient’s movement, heart rate, respiratory rate, the amount of oxygen in the blood, skin impedance and wheezing in the lungs.
The wristband focuses largely on environmental factors, monitoring volatile organic compounds and ozone in the air, as well as ambient humidity and temperature. The wristband also includes additional sensors to monitor motion, heart rate and the amount of oxygen in the blood.
The system also has one nonwearable component: a spirometer, which patients breathe into several times a day to measure lung function.
The HET system was developed by researchers from the National Science Foundation’s Nanosystems Engineering Research Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST) at North Carolina State University (NC State).
Alper Bozkurt, the principal investigator of a paper describing the work and an assistant professor of electrical and computer engineering at NC State, said: “Our goal was to design a wearable system that could track the wellness of the subjects and in particular provide the infrastructure to predict asthma attacks, so that the users could take steps to prevent them by changing their activities or environment.”
James Dieffenderfer, lead author of the paper, said: “Preventing an attack could be as simple as going indoors or taking a break from an exercise routine.
“Right now, people with asthma are asked to use a peak flow meter to measure lung function on a day-to-day basis. That information is used to inform the dosage of prescription drugs used in their inhalers.
“For HET, we developed a customised self-powered spirometer, which collects more accurate information on lung function and feeds that data into the system,” Dieffenderfer adds.
Data from all of these sensors is transmitted wirelessly to a computer, where custom software collects and records the data.
“The uniqueness of this work is not simply the integration of various sensors in wearable form factors,” said Veena Misra, co-author of the paper and a professor of electrical and computer engineering at NC State.
Misra continued: “The impact here is that we have been able to demonstrate power consumption levels that are in the sub-milliwatt levels by using nano-enabled novel sensor technologies.
“This ultra-low power consumption is important because it gives the devices a long battery life, and will make them compatible with the power generated by the body – which is not a lot,” says Misra, who is also the director of the ASSIST Center. “It enables a pathway to realise the ASSIST Center’s vision of wearable sensors powered by energy from the body in the near future.”
“This summer, we plan to begin testing HET in a controlled environment with subjects suffering from asthma and a control group, in order to identify which environmental and physiological variables are effective at predicting asthma attacks.”
Bozkurt said: “Once we have that data, the center can begin developing software that will track user data automatically and give users advance warning of asthma attacks.
“That software will allow users to synch the HET to their smartphones so that they can monitor their health on the go. After these tests are completed, and the prediction software created, we are hoping that a fully functional HET system will be available.”
The paper, “Low Power Wearable Systems for Continuous Monitoring of Environment and Health for Chronic Respiratory Disease,” is published in the IEEE Journal of Biomedical and Health Informatics.