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MU researchers monitor health with bed sensors

A look at the strip-like bed sensors under a mattress.

With the sensor, patients don’t have to be hooked up to bothersome monitors and leads because it’s sensitive enough to measure heart rate, respiration and level of restlessness from a nonintrusive position beneath a patient’s mattress. Photo courtesy of MU News Bureau.

A new study from MU researchers uses bed sensors to continuously monitor patients’ cardiac activity while they sleep.

Many people in the United States, especially the elderly, suffer from cardiovascular ailments and diseases, which increases the need to monitor and detect early signs of heart problems before they become worse.

One challenge with monitoring is that the systems used can often be intrusive and require the patient to be hooked up to wire leads. They can also affect the patient’s ability to continue living independently in a non-clinical environment. That’s where the MU’s hydraulic sensors can help.

Marjorie Skubic, MU professor of electrical and computer engineering and director of the MU Center for Eldercare and Rehabilitation Technology, said the bed sensors’ purpose is to detect any possible health problems while helping patients to “age in place” in the comfort of their own homes.

With the sensor, patients don’t have to be hooked up to bothersome monitors and leads because it’s sensitive enough to measure heart rate, respiration and level of restlessness from a nonintrusive position beneath a patient’s mattress.

“The person will not feel uncomfortable because it’s under the mattress,” Dominic Ho, an MU electrical and computer engineering professor who contributed to the study, said. “It’s just like sleeping as normal.”

This system works out well because during sleep is a prime time to monitor cardiac activity.

“Every day, we spend six to eight hours in bed,” Ho said. “We can actually measure the behavior of the person while he or she’s sleeping.”

The sensor consists of a pressure sensor and four water-filled tubes (transducers) that are used to capture ballistocardiogram signals, the measure of the ballistic forces of the heart. Useful inferences on the person’s health can then be gathered from the data, such as their heart health, how long or how often the person is in bed and even how restful the person’s sleep is.

“If someone is having a bad dream, then we actually find that his heart rate goes up, and then it goes back down,” Ho said. “So it’s a good model of behavior. You can tell how good the person is sleeping, whether they’re having bad dreams or not, and monitor activities that would indicate some health issue during the initial stage.”

“All of this gets used in our early illness detection system,” Skubic said.

Quick discovery of problems can allow them to be managed before they become more serious. Skubic said this is especially important for older patients, for whom early treatment of an illness could mean the difference between living at home or going to a skilled care facility.

Ho said that the sensor can still be refined, and in the future he said the team ultimately would like to be able to get these sensors on the market and in people’s homes. The MU bed sensor has already been licensed by one company who is using it as part of an early illness detection system for seniors.

“In the university, our job is to create new ideas and start with some new technologies,” Ho said. “Then we partner with other industrial people to enhance the sensor, make it better and then make it available to a wide number of people.”