Evaluation of key design parameters for mitigating motion artefact in the mobile reflectance PPG signal to improve estimation of arterial oxygenation

This article describes the design of a smart steering wheel intended for use in unobtrusive health and drowsiness monitoring. The aging population, cardiovascular disease, personalized medicine, and driver fatigue were significant motivations for developing a monitoring platform in cars because people spent much time in cars. The purpose was to create a unique, comprehensive monitoring system for the driver. The crucial parameters in health or drowsiness monitoring, such as heart rate, heart rate variability, and blood oxygenation, are measured by an electrocardiograph and oximeter integrated into the steering wheel. In addition, an inertial unit was integrated into the steering wheel to record and analyze the movement patterns performed by the driver while driving. The developed steering wheel was tested under laboratory and real-life conditions. The measured signals were verified by commercial devices to confirm data correctness and accuracy. The resulting signals show the applicability of the developed platform in further detecting specific cardiovascular diseases (especially atrial fibrillation) and drowsiness.

Section: Resultsmentioning

confidence: 99%

Design of Smart Steering Wheel for Unobtrusive Health and Drowsiness Monitoring

Babušiak

Hajdučík

Medvecky

et al. 2021

“…A means of effectively measuring human physiological factors, such as blood oxygen saturation (SpO2) and pulse rate (PR), plus analyzing the data and for decrement alerts, would allow us to more accurately assess and mitigate risk factors associated with human performance [ 14 ]. The advancement of sensing and wireless communication technologies has made it possible to develop systems to monitor these physiological activities continuously.…”

Section: Introductionmentioning

confidence: 99%

“…However, this configuration is not well suited to longer-term continuous, routine sensing because many activities involve use, or high movement, of the fingers, especially crucial for operators in extreme environments [ 10 ]. Typical PPG sensors are so sensitive to motion, that even the small movements of fingers have been shown to create signal artifacts which reduce the accuracy of the readings [ 14 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

“…As motion artifact is a well-known impediment for high-fidelity PPG sensor readings, signal noise reduction by using either signal processing algorithms or physical adaptations to sensor application, location, and overall system design is highly sought after [ 24 ]. The effect of several sensor design variables compounded with each other, such as sensor weight, relative motion, placement, and contact force against the skin, can further reduce motion artifact and increase accuracy and reliability of the system [ 14 , 25 ]. Additionally, measuring blood oxygenation directly to the brain, as opposed to extremities, is an important consideration in high-risk environments, where split-second decisions can be critical in preventing accidents.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Photoplethysmography behind the Ear Outperforms Electrocardiogram for Cardiovascular Monitoring in Dynamic Environments

Bradke

Miller

Everman

2021

An increasing proportion of occupational mishaps in dynamic, high-risk operational environments have been attributed to human error, yet there are currently no devices to routinely provide accurate physiological data for insights into underlying contributing factors. This is most commonly due to limitations of commercial and clinical devices for collecting physiological data in environments of high motion. Herein, a novel Photoplethysmography (PPG) sensor device was tested, called SPYDR (Standalone Performance Yielding Deliberate Risk), reading from a behind-the-ear location, specifically designed for high-fidelity data collection in highly dynamic high-motion, high-pressure, low-oxygen, and high-G-force environments. For this study, SPYDR was installed as a functional ear-cup replacement in flight helmets worn by rated US Navy aircrew. Subjects were exposed to reduced atmospheric pressure using a hypobaric chamber to simulated altitudes of 25,000 feet and high G-forces in a human-rated centrifuge up to 9 G acceleration. Data were compared to control devices, finger and forehead PPG sensors, and a chest-mounted 12-lead ECG. SPYDR produced high-fidelity data compared to controls with little motion-artifact controls in the no-motion environment of the hypobaric chamber. However, in the high-motion, high-force environment of the centrifuge, SPYDR recorded consistent, accurate data, whereas PPG controls and ECG data were unusable due to a high-degree-motion artifacts. The data demonstrate that SPYDR provides an accurate and reliable system for continuous physiological monitoring in high-motion, high-risk environments, yielding a novel method for collecting low-artifact cardiovascular assessment data important for investigating currently inaccessible parameters of human physiology.

“…Despite the susceptibility to motion artifacts, PPG technology is able to provide several physiological parameters associated to the cardiovascular system, such as HR, heart rate variability [ 13 , 14 , 15 ], blood oxygenation saturation [ 11 , 16 , 17 ], blood pressure [ 18 , 19 , 20 ] and arterial stiffness [ 21 , 22 ]. In particular, HR is one of the first parameters observed in order to monitor subject’s health in a wide range of situations, such as patient monitoring [ 23 ], training of athletes [ 24 ] and workers’ safeness [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Effect of Contact Pressure during Physical Activity on Photoplethysmographic Heart Rate Measurements

Scardulla

D’Acquisto

Colombarini

et al. 2020

Heart rate (HR) as an important physiological indicator could properly describe global subject’s physical status. Photoplethysmographic (PPG) sensors are catching on in field of wearable sensors, combining the advantages in costs, weight and size. Nevertheless, accuracy in HR readings is unreliable specifically during physical activity. Among several identified sources that affect PPG recording, contact pressure (CP) between the PPG sensor and skin greatly influences the signals. Methods: In this study, the accuracy of HR measurements of a PPG sensor at different CP was investigated when compared with a commercial ECG-based chest strap used as a test control, with the aim of determining the optimal CP to produce a reliable signal during physical activity. Seventeen subjects were enrolled for the study to perform a physical activity at three different rates repeated at three different contact pressures of the PPG-based wristband. Results: The results show that the CP of 54 mmHg provides the most accurate outcome with a Pearson correlation coefficient ranging from 0.81 to 0.95 and a mean average percentage error ranging from 3.8% to 2.4%, based on the physical activity rate. Conclusion: Authors found that changes in the CP have greater effects on PPG-HR signal quality than those deriving from the intensity of the physical activity and specifically, the individual best CP for each subject provided reliable HR measurements even for a high intensity of physical exercise with a Bland–Altman plot within ±11 bpm. Although future studies on a larger cohort of subjects are still needed, this study could contribute a profitable indication to enhance accuracy of PPG-based wearable devices.