Summary: Engineers and physicians have created a miniature, wireless polygraph-like system that adheres to the chest like a soft, lightweight bandage. Rather than focusing on detecting lies, the device continuously captures hidden physiological stress signals from the body without requiring access to chemical biomarkers in bodily fluids.
By streaming synchronized, real-time measurements of heart activity, respiration, sweat production, blood flow and skin temperature to a smartphone, the wearable provides objective, data-driven insight for patients who cannot reliably communicate pain or discomfort, including infants and older adults.
Key Facts
- Integrated Multimodal Sensing: The bandage-style device houses an array of miniature sensors in a single platform that weighs under 8 grams, monitoring five core physiological indicators of stress continuously for more than 24 hours.
- Reducing Clinical Subjectivity: Developed at the request of pediatricians at Ann & Robert H. Lurie Children’s Hospital of Chicago, the system aims to replace subjective nurse assessments and cry-based scoring with quantitative, round-the-clock metrics for infant stress.
- Validated in Real-World Conditions: In controlled tests the wearable matched commercial polygraph accuracy, tracked pupil-dilation changes during increased cognitive load, and detected sleep apnea and nighttime arousals in pediatric sleep studies.
- Performance Insights: During emergency-room training simulations, the data showed that participants with the largest physiological stress responses performed worse, illustrating how acute stress can impair critical decision-making.
Source: Northwestern University
Northwestern University engineers have developed a compact, wireless wearable polygraph system.
Unlike the dramatic polygraphs seen on television, this wearable system is not designed to catch lies. Instead, engineers and clinicians designed it to sense internal stress responses throughout the body — no interrogation required.
The lightweight, bandage-like patch adheres comfortably to the chest and simultaneously records cardiac signals, breathing patterns, sweat activity, near-surface blood flow and skin temperature. Together, these synchronized streams create a continuous, whole-body picture of physiological stress.
Tracking multiple signals at once allows clinicians to detect stress and potential discomfort in people who cannot communicate reliably, diagnose sleep-disordered breathing outside of cumbersome lab setups, monitor mental health over time, and detect early signs of medical complications.
The study describing the system was published in the journal Science Advances.
“The body often reveals stress before someone becomes consciously aware of it,” said John A. Rogers of Northwestern, who led the device development. “People may not realize the degree of pressure they are under, yet stress quietly affects health. Extended stress can be harmful, particularly for pregnant people, children and critically ill patients.
Quantitative, continuous stress monitoring could help individuals and clinicians intervene earlier with targeted, stress-reducing actions. We set out to build a device conceptually similar to a polygraph that relies on biophysical signals, without needing blood or saliva biomarkers.”
Rogers is the Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering, Biomedical Engineering and Neurological Surgery at Northwestern, with appointments in the McCormick School of Engineering and the Feinberg School of Medicine. He directs the Querrey Simpson Institute for Bioelectronics and the Querrey Simpson Institute for Translational Engineering and Advanced Medical Systems. Co-corresponding authors on the study are Dr. Debra E. Weese-Mayer, Beatrice Cummings Mayer Professor of Pediatric Autonomic Medicine and professor of pediatrics (neurology) at Feinberg, and Jae-Young Yoo of Sungkyunkwan University.
A voice for the vulnerable
The project began at the request of pediatricians at Ann & Robert H. Lurie Children’s Hospital of Chicago. Rogers’ group has previously developed wireless wearable electronics for infants and children to monitor vital signs, support illness tracking, enable treatments for congenital conditions and assist clinical diagnosis.
Pediatric clinicians asked for a soft, noninvasive device that could sense and continuously track stress in hospitalized infants without relying on biochemical measures such as saliva or blood. Currently, infant stress assessment depends heavily on caregivers’ observations — crying, facial expression and movement — alongside basic vitals. Those cues can be subtle or inconsistent, and infants cannot describe their own symptoms.
“Stress assessments are often subjective, recorded via surveys and nursing notes that include factors like the tone or volume of crying,” Rogers said. “Infants can’t report pain, so determining their stress level is extremely challenging. We wanted to remove subjectivity from that process.”
“This device continuously records the body’s stress signals, quantifying how long someone is stressed each day and how intense that stress is,” said Weese-Mayer. “Both patients and healthcare teams can now identify stress objectively and monitor whether interventions are effective, all in a noninvasive way.”
All-in-one stress sensing
Rogers and colleagues drew inspiration from polygraphs. While commonly called “lie detectors,” polygraphs actually measure physiological responses to stress, which can arise from many causes besides deception. Rogers aimed to capture those same stress-sensitive signals — and additional indicators — in one compact, fully integrated wearable.
The device integrates several tiny sensors into a single soft form factor. A motion sensor and miniature microphone detect mechanical and acoustic signals from the heart and lungs. Thermal sensors measure skin temperature and heat flow tied to near-surface blood circulation. Electrodermal sensors measure subtle changes in skin conductivity caused by sweat gland activity — a classic marker of nervous-system arousal.
“Stress is multidimensional,” Rogers said. “You cannot reliably infer stress from just one or two signals. We packed as many complementary physiological sensors as possible into a compact, lightweight platform while avoiding the need for biofluid sampling.”
Synchronized data streams are transmitted wirelessly to a smartphone, smartwatch or tablet where machine-learning algorithms analyze stress-related patterns in real time. Weighing less than 8 grams and designed to move naturally with the skin, the patch can operate continuously for over 24 hours.
Proven across realistic scenarios
The team validated the system in both controlled experiments and realistic clinical settings. In simulated polygraph tests the wearable captured stress responses to sensitive questions and closely matched readings from commercial polygraph systems.
In cognitive-demand tasks — such as understanding speech in noisy conditions — the device recorded clear increases in stress-related signals as task difficulty rose, aligning well with pupil-dilation measurements obtained simultaneously. During cold-pressor tests, when participants immersed their hands in ice water, coordinated changes appeared across heart rate, breathing, sweat and temperature signals.
In pediatric sleep studies, the wearable detected clinically important events — including breathing irregularities and nighttime awakenings — with performance comparable to hospital-grade sleep tests but with fewer disruptions to patients.
During emergency-room simulation training, the device revealed that stronger multimodal stress signatures correlated with poorer performance, highlighting potential value for medical education and performance management. “The device could trigger alerts to a user or caregiver when stress exceeds a set threshold,” Rogers said. “Many people underestimate how stressed they are and how that stress affects their performance.”
What’s next
The team plans to move beyond validation into broader clinical use. Next steps include testing in larger patient populations, improving personalization of stress detection, and integrating the technology into hospital and at-home monitoring systems for continuous, actionable health insight.
Researchers are also exploring additional sensors, including the potential to add electroencephalography (EEG). Adding brain activity measurements would extend the device from measuring peripheral stress responses to examining how the brain perceives and processes stress, helping distinguish stress from pain and deepening understanding of how these experiences relate to other physiological markers.
“We live in stressful times without widespread tools to detect stress proactively,” Weese-Mayer said. “Identifying stress earlier — whether environmental or disease-related — makes it possible to intervene before harmful effects become irreversible.”
The study, “Wireless, skin-interfaced multimodal sensing system for continuous psychophysiological monitoring — a wearable polygraph device,” received support from the Querrey Simpson Institute for Bioelectronics.
Key Questions Answered:
A: Technically, the device can detect stress responses similar to a conventional polygraph and matched commercial systems during validation tests. However, its intended purpose is clinical: to detect physiological stress early and objectively in medical settings rather than to adjudicate truthfulness.
A: The patch combines multiple miniature sensors. A microphone and motion sensor capture mechanical and acoustic signals from the heart and lungs. Thermal sensors monitor skin temperature and heat flow related to near-surface circulation. Electrodermal sensors measure tiny conductivity changes linked to sweat gland activity.
A: Infant stress and pain are currently assessed subjectively, often by scoring crying and behavior. This wearable removes much of that uncertainty by providing objective, continuous measurements of physiological stress, giving clinicians a 24-hour view of stress burden and the ability to monitor whether treatments are effective.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by staff.
About this stress and neurotech research news
Author: Amanda Morris
Source: Northwestern University
Contact: Amanda Morris – Northwestern University
Image: Image credit: John A. Rogers/Northwestern University
Original Research: Open access. “Wireless, skin-interfaced multimodal sensing system for continuous psychophysiological monitoring – a wearable polygraph device” by Sun Hong Kim et al., published in Science Advances. DOI: 10.1126/sciadv.aed3162
Abstract
Wireless, skin-interfaced multimodal sensing system for continuous psychophysiological monitoring – a wearable polygraph device
Accurate, continuous monitoring of psychophysiological states is essential to understanding stress and autonomic dysfunction across many medical contexts. Existing methods, including polygraphy and polysomnography, depend on bulky wired sensors that limit real-world use and burden vulnerable patients like infants.
We introduce a wireless, skin-mounted multimodal sensing system capable of recording cardiac, respiratory, electrodermal and thermal signals in a time-synchronized way. Built with compact, soft designs, the technology enables unobtrusive monitoring in laboratory, clinical and naturalistic environments.
Validation studies against gold-standard systems show high fidelity in quantifying stress responses during polygraph-style interviews, cognitive load tasks and cold-pressor tests. In pediatric sleep research, the device reliably identifies arousals, hypopneas and apneas and reveals autonomic signatures in infants with specific conditions. Real-world deployment during emergency simulation training demonstrated an inverse relationship between multimodal stress signatures and performance, highlighting translational value for medical education.
Machine-learning analyses across studies confirm that multimodal features outperform single-signal approaches for detecting stress and clinical events with high sensitivity and specificity. Overall, this platform bridges engineering innovation and clinical practice, offering mechanistic insight and diagnostic potential across stress medicine, sleep medicine and beyond.