At the beginning of the Covid pandemic, Weizmann Institute of Science Prof. Yonina Eldar launched an unusual appeal. 

The Israel Prize laureate called upon physicians from across Israel to join her online in a brainstorming session to identify the most pressing needs of an overloaded healthcare system. 

“In the midst of the health crisis, I felt frustrated to just be sitting back and not doing enough,” she recalls.

One problem raised during that session was the risk of spreading the coronavirus infection by physical contact while monitoring hospital patients. 

“Addressing this problem fit in well with my research interests,” Eldar says. “It had long bothered me that when it comes to technological innovations, the world of health lags far behind areas such as communications or entertainment.”

Why, she wondered, can we make calls or play computer games hands-free, but doctors still typically use a physical stethoscope to examine a patient as they did a century ago?

At the time of the pandemic, Eldar had just joined the Weizmann’s computer science and applied mathematics department, where her lab developed innovative technologies for processing signals and information in fields including medicine. 

She and her team decided to develop an entirely new technology for remotely checking health using radar.

Radar for health detection

Radar systems are often used for military purposes such as detecting aircraft or ships. But they also have civilian applications. 

For instance, in the vehicle industry radar is used to detect and track objects by emitting electromagnetic waves and interpreting the changes that occur in these waves as they bounce back after hitting the object. 

Eldar had worked with radar previously in connection with autonomous cars and defense applications. 

“Radar devices are small, inexpensive and convenient, and they emit waves that are safe for humans. They’ve been used, for example, to count the number of people in a room or make sure no baby is left behind in a car. So I thought, Why not apply radar to monitor patients remotely?”

BRAHMS

Following five years of development, Eldar’s lab has unveiled BRAHMS, the Bio-Radar Health Monitoring System.

BRAHMS continuously monitors vital signs from a distance by tracking subtle chest movements and interpreting them using a sophisticated algorithm developed by Eldar’s team. 

The system currently can measure heart rate (pulse) and breathing rate as well as lung function. In the future, it may also be equipped to measure blood pressure and breathing patterns, which could help detect sleep apnea.

BRAHMS can reliably monitor several people simultaneously, even in noisy, crowded environments. It identifies all the people in the room, measures their vital signs without contact and sends the measurements to a monitor. The medical staff is automatically alerted if a worrying change is detected.

The millimeter wave (mmWave) frequency spectrum employed by the BRAHMS radar system is sufficiently sensitive to detect a displacement of several millimeters, enough to track the tiny chest movements of a sleeping infant even through clothing or bedding.

The typical maximum range of the proposed system in indoor settings, such as homes or hospital rooms, is nine meters (29.5 feet). 

ICUs, ERs and more

Eldar says that once BRAHMS is developed for commercial use, a compact model could be installed in emergency rooms or intensive care units, postoperative care units or homes for the elderly. The system would also be good for pediatric patients, who don’t like being hooked up to devices.

Eldar points out that in addition to reducing the risk of spreading infections, noncontact radar sensing would eliminate patient discomfort and the hassle of wires getting tangled or pulled off. 

In fact, some 40 percent of intensive care unit patients are estimated to experience skin irritation, dislodged wires or other complications related to bedside monitoring devices, 

The BRAHMS technology was created using a systems engineering approach – a combination of engineering, mathematics and wave motion physics. 

The development team included PhD student Yonathan Eder, who led the research; algorithm development expert Luda Nisnevich; engineers Shlomi Savariego and Moshe Namer; and clinical manager Dr. Adi Wegerhoff.

Eldar, who heads the Manya Igel Center for Biomedical Engineering and Signal Processing, receives support for her research from the Swiss Society Institute for Cancer Prevention Research and the Dr. Gilbert S. Omenn and Martha A. Darling Weizmann Institute – Schneider Hospital Fund for Clinical Breakthroughs through Scientific Collaborations.