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A Comparative Study of Physiological Monitoring with a Wearable Opto-Electronic Patch Sensor (OEPS) for Motion Reduction.

Alzahrani A, Hu S, Azorin-Peris V - Biosensors (Basel) (2015)

Bottom Line: The protocol involved 16 healthy subjects and was designed to test the features of OEPS, with emphasis on the effective reduction of motion artefacts through the utilization of a 3MA as a movement reference.The results show significant agreement between the heart rates from the reference measurements and the recovered signals.The outcome of the present work incites the prospects of OEPS on physiological monitoring during physical activities.

View Article: PubMed Central - PubMed

Affiliation: School of Electronic, Electrical and Systems Engineering, Loughborough University, Ashby Road, Loughborough, Leicestershire LE11 3TU, UK. A.Alzahrani@lboro.ac.uk.

ABSTRACT
This paper presents a comparative study in physiological monitoring between a wearable opto-electronic patch sensor (OEPS) comprising a three-axis Microelectromechanical systems (MEMs) accelerometer (3MA) and commercial devices. The study aims to effectively capture critical physiological parameters, for instance, oxygen saturation, heart rate, respiration rate and heart rate variability, as extracted from the pulsatile waveforms captured by OEPS against motion artefacts when using the commercial probe. The protocol involved 16 healthy subjects and was designed to test the features of OEPS, with emphasis on the effective reduction of motion artefacts through the utilization of a 3MA as a movement reference. The results show significant agreement between the heart rates from the reference measurements and the recovered signals. Significance of standard deviation and error of mean yield values of 2.27 and 0.65 beats per minute, respectively; and a high correlation (0.97) between the results of the commercial sensor and OEPS. T, Wilcoxon and Bland-Altman with 95% limit of agreement tests were also applied in the comparison of heart rates extracted from these sensors, yielding a mean difference (MD: 0.08). The outcome of the present work incites the prospects of OEPS on physiological monitoring during physical activities.

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Recoveries of PPG signal after applying vector magnitude.
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biosensors-05-00288-f009: Recoveries of PPG signal after applying vector magnitude.

Mentions: Once the vector magnitude algorithm is used to produce the reference signal, and following the initial noise cancellation stage, the peaks of the signal can be detected, but there are still some uncorrelated values between the prime processed PPG signals and reference 3MA signals. Figure 9 shows a representative PPG signal that was recovered using the 3MA as a reference for motion. Here, the measurement was taken from the palm during fast walking (6 km/h) exercise, with the 3MA attached on the back of the patch sensor. At this stage, the troughs of the signal are visible but the signal still requires further processing. In order to provide a more stable PPG signal, the adaptive filter for reducing motion artefacts was set to a filter order of 32 and a step size of μ = 0.1. A Butterworth low-pass filter (16th order, finite impulse response, 5 Hz cut-off) was also used in order to eliminate any further high noise that was out of the frequency range of interest, of 1–5 Hz, as shown in Figure 10.


A Comparative Study of Physiological Monitoring with a Wearable Opto-Electronic Patch Sensor (OEPS) for Motion Reduction.

Alzahrani A, Hu S, Azorin-Peris V - Biosensors (Basel) (2015)

Recoveries of PPG signal after applying vector magnitude.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493550&req=5

biosensors-05-00288-f009: Recoveries of PPG signal after applying vector magnitude.
Mentions: Once the vector magnitude algorithm is used to produce the reference signal, and following the initial noise cancellation stage, the peaks of the signal can be detected, but there are still some uncorrelated values between the prime processed PPG signals and reference 3MA signals. Figure 9 shows a representative PPG signal that was recovered using the 3MA as a reference for motion. Here, the measurement was taken from the palm during fast walking (6 km/h) exercise, with the 3MA attached on the back of the patch sensor. At this stage, the troughs of the signal are visible but the signal still requires further processing. In order to provide a more stable PPG signal, the adaptive filter for reducing motion artefacts was set to a filter order of 32 and a step size of μ = 0.1. A Butterworth low-pass filter (16th order, finite impulse response, 5 Hz cut-off) was also used in order to eliminate any further high noise that was out of the frequency range of interest, of 1–5 Hz, as shown in Figure 10.

Bottom Line: The protocol involved 16 healthy subjects and was designed to test the features of OEPS, with emphasis on the effective reduction of motion artefacts through the utilization of a 3MA as a movement reference.The results show significant agreement between the heart rates from the reference measurements and the recovered signals.The outcome of the present work incites the prospects of OEPS on physiological monitoring during physical activities.

View Article: PubMed Central - PubMed

Affiliation: School of Electronic, Electrical and Systems Engineering, Loughborough University, Ashby Road, Loughborough, Leicestershire LE11 3TU, UK. A.Alzahrani@lboro.ac.uk.

ABSTRACT
This paper presents a comparative study in physiological monitoring between a wearable opto-electronic patch sensor (OEPS) comprising a three-axis Microelectromechanical systems (MEMs) accelerometer (3MA) and commercial devices. The study aims to effectively capture critical physiological parameters, for instance, oxygen saturation, heart rate, respiration rate and heart rate variability, as extracted from the pulsatile waveforms captured by OEPS against motion artefacts when using the commercial probe. The protocol involved 16 healthy subjects and was designed to test the features of OEPS, with emphasis on the effective reduction of motion artefacts through the utilization of a 3MA as a movement reference. The results show significant agreement between the heart rates from the reference measurements and the recovered signals. Significance of standard deviation and error of mean yield values of 2.27 and 0.65 beats per minute, respectively; and a high correlation (0.97) between the results of the commercial sensor and OEPS. T, Wilcoxon and Bland-Altman with 95% limit of agreement tests were also applied in the comparison of heart rates extracted from these sensors, yielding a mean difference (MD: 0.08). The outcome of the present work incites the prospects of OEPS on physiological monitoring during physical activities.

Show MeSH