Wireless sensor gently sits on throat to
monitor coughs, fever and respiratory activity
The more we learn about the novel
coronavirus (COVID-19), the more unknowns seem to arise. These ever-emerging
mysteries highlight the desperate need for more data to help researchers and
physicians better understand — and treat — the extremely contagious and deadly
disease.
Researchers at Northwestern University and
Shirley Ryan AbilityLab in Chicago have developed a novel wearable device and
are creating a set of data algorithms specifically tailored to catch early
signs and symptoms associated with COVID-19 and to monitor patients as the
illness progresses.
Capable of being worn 24/7, the device
produces continuous streams of data and uses artificial intelligence to uncover
subtle, but potentially life-saving, insights. Filling a vital data gap, it
continuously measures and interprets coughing and respiratory activity in ways
that are impossible with traditional monitoring systems.
Developed in an engineering laboratory at
Northwestern and using custom algorithms being created by Shirley Ryan
AbilityLab scientists, the devices are currently being used in a study at Shirley
Ryan AbilityLab by COVID-19 patients and the healthcare workers who treat them.
About 25 affected individuals began using the devices two weeks ago. They are
being monitored both in the clinic and at home, totaling more than 1,500
cumulative hours and generating more than one terabyte of data.
About the size of a postage stamp, the
soft, flexible, wireless, thin device sits just below the suprasternal notch —
the visible dip at the base of the throat. From this location, the device
monitors coughing intensity and patterns, chest wall movements (which indicate
labored or irregular breathing), respiratory sounds, heart rate and body
temperature, including fever. From there, it wirelessly transmits data to a
HIPAA-protected cloud, where automated algorithms produce graphical summaries
tailored to facilitate rapid, remote monitoring.
“The most recent
studies published in the Journal of the American Medical Association suggest
that the earliest signs of a COVID-19 infection are fever, coughing and
difficulty in breathing. Our device sits at the perfect location on the body —
the suprasternal notch — to measure respiratory rate, sounds and activity
because that’s where airflow occurs near the surface of the skin,” said
Northwestern’s John A. Rogers, who led the technology development. “We
developed customized devices, data algorithms, user interfaces and cloud-based
data systems in direct response to specific needs brought to us by frontline
healthcare workers. We’re fully engaged in contributing our expertise in bioelectronic
engineering to help address the pandemic, using technologies that we are able
to deploy now, for immediate use on actual patients and other affected
individuals. The measurement
capabilities are unique to this device platform — they cannot be accomplished
using traditional watch or ring-style wearables that mount on the wrist or the
finger.”
“We anticipate that
the advanced algorithms we are developing will extract COVID-like signs and
symptoms from the raw data insights and symptoms even before individuals may
perceive them,” said Arun Jayaraman, a research scientist at Shirley Ryan
AbilityLab, who is leading the algorithm development. “These sensors have the
potential to unlock information that will protect frontline medical workers and
patients alike — informing interventions in a timely manner to reduce the risk
of transmission and increase the likelihood of better outcomes.”
Continuous monitoring from hospital to
home
The mysterious ways that COVID-19 affects
the body seem to get stranger and stranger. Many patients’ symptoms fully
disappear before they suddenly and unexpectedly begin deteriorating — sometimes
within a matter of hours. Other patients have recovered and tested “negative”
but later test “positive” again.
The unknowns underscore the need for
continuous patient monitoring to ensure that physicians can intervene at the
slightest sign of trouble. The Northwestern and Shirley Ryan AbilityLab teams’
device provides around-the-clock monitoring for COVID-19 patients and those
exposed to them.
“Having the ability to
monitor ourselves and our patients — and being alerted to changing conditions
in real time — will give clinicians a new and important tool in the fight
against COVID-19,” said Dr. Mark Huang, a physician at Shirley Ryan AbilityLab,
who has worn the sensor. “The sensor also will offer clinicians and patients
peace of mind as it monitors COVID-like symptoms, potentially prompting earlier
intervention and treatment.”
The device can monitor hospitalized
patients and then be taken home to continue 24/7 supervision. The real-time
data streaming from patients gives insights into their health and outcomes that
is currently not being captured or analyzed by traditional monitoring systems.
“Nobody has ever
collected this type of data before,” Rogers said. “Earlier detection is always
better and our devices provide important and unique capabilities in that
context. For patients who have contracted the disease, the value is even more
clear, as the data represent quantitative information on respiratory behavior,
as a mechanism to track the progression and/or the effects of treatments.”
“Nobody has ever collected this type of
data before,” John A. Rogers, biomedical engineer.
“This opens up new
telemedicine strategies as we won’t have to bring in patients for monitoring,”
Jayaraman said. “Physicians can potentially review the patients’ data for
hours, days or weeks, immediately through a customized graphical user interface
to a cloud data management system that is being set up for this purpose, to see
an overall image of how the patient is doing.”
Although the wearable device is currently
unable to measure blood oxygenation levels, which is an important component of
lung health, the team plans to incorporate this capability in its next round of
devices. The Rogers lab has already successfully incorporated this capability
in its previous work to produce clinical grade-monitoring devices for intensive
care units. Rogers believes they can easily apply that research to the
COVID-tailored devices.
Warning system for the most at-risk
Not only can the device monitor the progress of COVID-19 patients, it could also provide early warning signals to the frontline workers who are most at risk for catching this remarkably infectious disease. The device offers the potential to identify symptoms and to pick up trends before the workers notice them, thereby providing an opportunity to engage in appropriate precautionary measures and to seek further testing as quickly as possible.
“People with obvious, severe symptoms are going to the hospital, being tested or being told to self-isolate,” Jayaraman said. “For those who have symptoms they perceive as mild or seasonal allergies, there is no warning system. They could be in contact with others and unknowingly spread infection.”
Assessing efficacy of new therapeutics
As researchers rush for a COVID-19 cure,
physicians have been trying exploratory, sometimes unproven, treatments to help
their patients. This is another area where Rogers’ and Jayaraman’s device can
play a role.
“Early reports of
certain proposed treatments suggest that they can eliminate coughing symptoms
more quickly than a placebo,” Rogers said. “Nobody, however, is quantifying
certain key symptoms, such as coughing — duration, frequency, amplitude, sounds,
etc. Our device allows for precision measurement of this essential, yet
currently unquantified, aspect of the disease.”
In the future, this sensor package could
help researchers and physicians quantify which therapeutics are working best.
“At the simplest
level, our systems allow assessments based on data, in a quantitative way,
without relying on human judgment of whether a patient is coughing more or
less,” Rogers said.
Device initially conceived for stroke
patients
The new device builds on recent research
from a collaboration between Rogers’ and Jayaraman’s labs, first published on
the cover of the February 2020 issue of Nature Biomedical Engineering, with a
focus on monitoring swallowing and speech disorders in patients recovering from
stroke. These sensors work by precisely measuring vibratory signatures from the
throat and chest. By measuring vibrations rather than acoustics, the team
avoids noise from background sounds and it bypasses privacy issues.
In response to requests and inquiries from the
medical community, Rogers and Jayaraman realized they could use this technology
to measure the vibratory signatures of COVID-like symptoms, including chest
wall movements and cough.
“As the algorithm becomes smarter, our hope
is that it will begin to discriminate among which coughs are COVID-like and
which are from something more benign,” Arun Jayaraman, Shirley Ryan AbilityLab.
Jayaraman’s team is developing custom
signal processing and machine-learning algorithms to train the device how to
recognize coughs in the data.
“As the algorithm
becomes smarter, our hope is that it will begin to discriminate among which
coughs are COVID-like and which are from something more benign,” Jayaraman
said. “The most basic approach, already deployed on COVID-19 patients and
health care workers, simply counts coughs and their intensity.”
More advanced analytics packages will be
available within the next few weeks.
Bypassing already-stressed supply chains
Thanks to a generous gift from Northwestern
University trustees Kimberly K. Querrey (’24 P) and Louis A. Simpson (’58, ’96
P), Rogers and his team are able to respond quickly to requests for devices.
Leveraging a set of manufacturing tools available in the new Simpson Querrey
Biomedical Research Building in Chicago, the team is already producing dozens
of devices per week. Rogers estimates that his team could produce up to
hundreds of devices per week — all in house, largely bypassing the need for
external vendors and complex supply chains.
“Quickly developing
new technologies internally has never been more crucial,” Querrey said. “This
work proves the power of STEM and why it’s so critical to the University and
beyond to have world-class researchers like John. I am so proud of John and his
team, while working remotely, for thinking outside the box and using their
collaborations to help protect our healthcare workers. We are excited to be
able to develop these devices within the University and get them in the hands
of those needing them most. The ability to measure vibratory signatures could
really help with early detection of COVID-19.”
“This crucial
philanthropic support has allowed us to develop and deploy the devices and an
associated software infrastructure almost immediately, within days, after we
started receiving requests from the medical community — without waiting for
external vendors, most of which are mostly shut down with the stay-at-home
orders,” Rogers said. “In this way, we avoid already-stressed supply chains. We
just do it ourselves.”
Comfortable and easy to use
In mid-March, Kelly McKenzie felt foggy and
developed a low-grade headache. Having recently returned from a work-related
trip overseas, she assumed it was jetlag. But as her symptoms progressed to
include cough and congestion, she started to worry. Although her symptoms were
not severe enough to seek COVID-19 testing, she knew she should self-isolate.
“Between my
international travel and the symptoms, my director and I decided it was best
for me to stay home from work, so I wasn’t bringing anything contagious into
the hospital,” said McKenzie, who is a research physical therapist at Shirley
Ryan AbilityLab.
“After you have worn it for a while, you
don’t even notice it,” Kelly McKenzie, pilot study participant.
McKenzie joined the pilot study to test the
device and train the algorithm with her symptoms. After wearing the sensor
around the clock for a week, she was amazed by the comfort of the soft silicone
material and ease of use. Wearers simply charge the device, put it on and it
immediately begins to work — streaming real-time data to a smartphone or
tablet.
“When you first put it
on, you can feel it just because it’s new and different,” McKenzie said. “But
after you have worn it for a while, you don’t even notice it.”
Because it is fully encased without wires,
electrodes, charge ports or removable batteries, the device can be worn while
exercising or in the shower. It turns out this also is important for
sterilization and reuse.
“This is absolutely
critical for use in the context of this extremely contagious disease,” Rogers
said. “Because it is fully sealed in a soft biocompatible silicone material, it
can be completely immersed in alcohol, and then exposed to a gas-based system
for rigorous sterilization. If there were exposed regions, or plugs or ports or
other physical interfaces, the device would not be relevant for this
application.”
What’s next?
In the coming weeks, the Northwestern and
Shirley Ryan AbilityLab teams will continue collecting patient data to
strengthen their algorithms — through deployments both in the clinic and at
home. They also are responding to other requests for access to the technology,
across the medical complex in Chicago. Additional deployments are starting now.
Rogers and Jayaraman also are examining
data from patients recovering from COVID-19, attempting to determine when they
are no longer contagious. Some of the patients wearing the device have been
dismissed from the acute-care hospital and are rehabilitating at Shirley Ryan
AbilityLab. In the future, this device could help determine whether post-COVID
patients still have minor, perhaps imperceptible symptoms.
Rogers hopes the device will not just tell
physicians how to best treat COVID-19 but also inform researchers about the
nature of the virus itself.
“The growing amount of
information and understanding around COVID-19 as a disease will be critically
important to containing and treating the current outbreak as well as those that
might occur in the future,” he said. “We hope, and we believe, that these
devices may help in these efforts by identifying and quantifying
characteristics and essential features of cough and respiratory activity
associated with this disease.”
To accelerate the deployment of this
device, the team recently launched a lean engineering-centric company, Sonica
Health, based on intellectual property (IP) jointly developed by Northwestern
and the Shirley Ryan AbilityLab. The IP related to this project has been
optioned and is being licensed through Northwestern's Innovation and New
Ventures Office. Exploring use of the device for the COVID-19 response is
supported by the Biomedical Advanced Research and Development Authority
(BARDA), part of the Office of the Assistant Secretary for Preparedness and
Response at the U.S. Department of Health and Human Services.
BARDA invests in the innovation, advanced
research and development, acquisition and manufacturing of medical
countermeasures — vaccines, drugs, therapeutics, diagnostic tools and
non-pharmaceutical products needed to combat health security threats. To date,
54 BARDA-supported products have achieved regulatory approval, licensure or
clearance. DRIVe (Division of Research, Innovation and Ventures) within BARDA,
catalyzes the development of innovative products and approaches, like the
Sonica Health technology, with the aim of solving major health security
challenges.
This wireless sensor project is one of
several current efforts led by Northwestern researchers who are on the front
lines of the COVID-19 crisis.
About the researchers
A world-renowned bioelectronics pioneer,
Rogers is the Louis Simpson and Kimberly Querrey Professor of Materials Science
and Biomedical Engineering in Northwestern’s McCormick School of Engineering,
professor of neurological surgery in the Feinberg School of Medicine and
director of the Querrey Simpson Institute for Bioelectronics.
A leading expert on wearable technology,
Jayaraman is the director of the Max Näder Center for Rehabilitation
Technologies and Outcomes Research at Shirley Ryan AbilityLab. He also is an
associate professor of physical medicine and rehabilitation at Feinberg.
Research contributors include Anthony
Banks, Shuai (Steve) Xu, Hyoyoung Jeong, Jongyoon Lee, Peter Lee, Lisa
Crossman, J.K. Chang, Andreas Tzavelis and Xiaoyue Ni from Northwestern and
Chaithanya K. Mummidisetty, Nicholas Shawen, Luca Lonini, Sung Yul Shin and
Chandra Jayaraman from Shirley Ryan AbilityLab.
Editor's note: Rogers, Xu and Banks have
financial interests in Sonica Health.
