Sample entropy is an effective nonlinear index for analyzing pulse rate variability (PRV) signal, but it has problems with a large amount of calculation and time consumption. Therefore, this study ...proposes a fast sample entropy calculation method to analyze the PRV signal according to the microprocessor process of data updating and the principle of sample entropy. The simulated data and PRV signal are employed as experimental data to verify the accuracy and time consumption of the proposed method. The experimental results on simulated data display that the proposed improved sample entropy can improve the operation rate of the entropy value by a maximum of 47.6 times and an average of 28.6 times and keep the entropy value unchanged. Experimental results on PRV signal display that the proposed improved sample entropy has great potential in the real-time processing of physiological signals, which can increase approximately 35 times.
The main aim of this work is to identify alterations in the morphology of the pulse photoplethysmogram (PPG) signal, due to the exposure of the subjects to a hyperbaric environment. Additionally, ...their Pulse Rate Variability (PRV) is analysed to characterise the response of their Autonomic Nervous System (ANS). To do that, 28 volunteers are introduced into a hyperbaric chamber and five sequential stages with different atmospheric pressures from 1 atm to 5 atm are performed. In this work, nineteen morphological parameters of the PPG signal are analysed: the pulse amplitude; eight parameters related to pulse width; eight parameters related to pulse area; and the two two pulse slopes. Also, classical time and frequency parameters of PRV are computed. Notable widening of the pulses width is observed in the stages analysed. The PPG area increases with pressure, with no significant changes when the initial pressure is recovered. These changes in PPG waveform may be caused by an increase in the systemic vascular resistance as a consequence of of vasoconstriction in the extremities, suggesting a sympathetic activation. However, the PRV results show an augmented parasympathetic activity and a reduction in the parameters that characterise the sympathetic response. So, only a sympathetic activation is detected in the peripheral region, as reflected by PPG morphology. The information regarding the ANS and the cardiovascular response that can be extracted from the PPG signal, as well as its compatibility with wet conditions make this signal the most suitable for studying the physiological response in hyperbaric environments.
Modified Barium Swallow Studies (MBSS) are a critical part of the evaluation, treatment planning, and outcome assessment for persons with swallowing disorders. Since MBSSs use ionizing radiation with ...associated cancer risks, many clinicians have reduced radiation exposure by reducing the fluoroscopic pulse rate. However, by reducing pulse rate, we also decrease the temporal resolution of MBSSs which has been shown in pilot studies to significantly reduce diagnostic accuracy. Two hundred MBSSs from patients routinely undergoing MBSS as standard of care conducted at 30 pulses per second (pps) using the Modified Barium Swallow Study Impairment Profile (MBSImP™) standardized administration protocol were selected. A stratified sampling method ensured that a full range of swallowing impairments (etiology, type, and severity) was represented. Recordings were down sampled from 30 pps to 15, 7.5, and 4 pps. MBSSs were rated using the MBSImP components and Penetration-Aspiration Scale (PAS) score for each swallow. Percent agreement was calculated across raters for MBSImP and PAS scores by bolus type and volume. The Least-Squares Method was used for hypothesis testing. Statistically significant and clinically meaningful changes in scores of swallowing physiology and penetration/aspiration occurred when reducing pulse rate below 30pps. These changes were evident across bolus types and volumes. Given the impact on diagnostic accuracy and the low radiation risks to adults undergoing MBSSs, reducing pulse rate to 15pps or below is not aligned with the As Low As Reasonably Achievable (ALARA) principle and should not be used as a viable method to reduce radiation exposure from MBSSs.
Remote photoplethysmography (rPPG) enables contact-free monitoring of the pulse rate by using a color camera. The fundamental limitation is that motion artifacts and changes in ambient light ...conditions greatly affect the accuracy of pulse-rate monitoring. We propose use of a high-speed camera and a motion suppression algorithm with high computational efficiency. This system incorporates a number of major improvements including reproduction of pulse wave details, high-precision pulse-rate monitoring of moving subjects, and excellent scene scalability. A series of quantization methods were used to evaluate the effect of different frame rates and different algorithms in pulse-rate monitoring of moving subjects. The experimental results show that use of 180-fps video and a Plane-Orthogonal-to-Skin (POS) algorithm can produce high-precision pulse-rate monitoring results with mean absolute error can be less than 5 bpm and the relative accuracy reaching 94.5%. Thus, it has significant potential to improve personal health care and intelligent health monitoring.
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Thermal comfort prediction of building occupants can be remarkably instrumental for both ensuring a comfortable living environment, and improving building energy-efficiency through strategic ...ambient-control based on the occupant's thermal state index (TSI: Cool-Discomfort/Comfort/Warm-Discomfort). This paper proposes a personal TSI prediction method termed as the enhanced Predicted Thermal State (ePTS) method by sensing physiological parameters namely, hand skin temperature and pulse rate, along with the ambient air temperature. The ePTS method is developed through significant enhancements over our previous skin temperature based PTS model. First, we investigate pulse rate as a potential TSI predictor. Second, we propose a logic-gated normalization process to address the individual differences in pulse rate. Third, we develop a spectral analysis approach to formulate a new pulse rate feature. Consequently, six significant TSI predictive features are curated that map the TSI based on an optimized Support Vector Machine algorithm. The method is compared with 5 different input cases and 3 state-of-the-art methods. Pulse rate is revealed to be a significant TSI predictor subject to the occupant's gender and BMI. The ePTS method achieves the highest accuracy at over 97%, outperforming the PTS model (82%), and other physiology based methods (82%–94%). The study is substantiated with extensive real human experiments in regulated thermal environment. The method is deemed adaptive by its machine-learning framework, robust by normalization, and non-intrusive by convenience of measurement. It may be realized by integrating the wearable and ambient sensor networks with the Internet-of-Things for a comfortable and energy-efficient building.
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•Novel TSI prediction method using skin temperature, pulse rate and air temperature.•Novel normalization process addresses individual differences in occupant pulse rate.•Spectral analysis method extracts new pulse rate feature for modeling.•SVM based ePTS method at 97% accuracy outperforms 5 input cases & 3 existing methods.•Occupants' thermal comfort prediction can improve building energy efficiency.
Objective: Neonates and infants are patients who would benefit from less invasive vital sign sensing, especially from fewer cables and the avoidance of adhesive electrodes. Photoplethysmography ...imaging (PPGI) has been studied for medical applications in recent years: it is possible to assess various vital signs remotely, non-invasively, and without contact by using video cameras and light. However, studies on infants and especially on neonates in clinical settings are still rare. Hence, we conducted a single-center study to assess heart activity by estimating the pulse rate (PR) of 19 neonates. Approach: Time series were generated from tracked regions of interest (ROIs) and PR was estimated via a joint time-frequency analysis using a short-time Fourier transform. Artifacts, for example, induced by movement, were detected and flagged by applying a signal quality index in the frequency domain. Main results: The feasibility of PR estimation was demonstrated using visible light and near-infrared light at 850 nm and 940 nm, respectively: the estimated PR was as close as 3 heartbeats per minute in artifact-free time segments. Furthermore, an improvement could be shown when selecting the best performing ROI compared to the ROI containing the whole body. The main challenges are artifacts from motion, light sources, medical devices, and the detection and tracking of suitable regions for signal retrieval. Nonetheless, the PR extracted was found to be comparable to the contact-based photoplethysmography reference and is, therefore, a viable replacement if robust signal retrieval is ensured. Significance: Neonates are seldom measured by PPGI and studies reporting measurements on darker skin tones are rare. In this work, not only a single camera was used, but a synchronized camera setup using multiple wavelengths. Various ROIs were used for signal extraction to examine the capabilities of PPGI. In addition, qualitative observations regarding camera parameters and noise sources were reported and discussed.
Remote camera-based measurement of physiology has great potential for healthcare and affective computing. Recent advances in computer vision and signal processing have enabled photoplethysmography ...(PPG) measurement using commercially available cameras. However, there remain challenges in recovering accurate noncontact PPG measurements in the presence of rigid head motion. When a subject is moving, their face may be turned away from one camera, be obscured by an object, or move out of the frame resulting in missing observations. As the calculation of pulse rate variability (PRV) requires analysis over a time window of several minutes, the effect of missing observations on such features is deleterious. We present an approach for fusing partial color-channel signals from an array of cameras that enable physiology measurements to be made from moving subjects, even if they leave the frame of one or more cameras, which would not otherwise be possible with only a single camera. We systematically test our method on subjects (N=25) using a set of six, 5-min tasks (each repeated twice) involving different levels of head motion. This results in validation across 25 h of measurement. We evaluate pulse rate and PRV parameter estimation including statistical, geometric, and frequency-based measures. The median absolute error in pulse rate measurements was 0.57 beats-per-minute (BPM). In all but two tasks with the greatest motion, the median error was within 0.4 BPM of that from a contact PPG device. PRV estimates were significantly improved using our proposed approach compared to an alternative not designed to handle missing values and multiple camera signals; the error was reduced by over 50%. Without our proposed method, errors in pulse rate would be very high, and estimation of PRV parameters would not be feasible due to significant data loss.
Background: Hypertension is included in 15 major causes of death in the United States. Primary prevention and prompt treatment of hypertension can prevent mortality. Previous research on salat ...revealed that prayer provides a feeling of relaxation and activates parasympathetic activation, affecting the cardiovascular system. Objective: This study aims to investigate the effect of salat on blood pressure (BP) and pulse in patients with stage one primary hypertension.Methods: This is a quasi-experimental study with a non-equivalent pre- and post-test control group design. The sample was taken by purposive sampling method. Thirty-six outpatients with stage one primary hypertension who met the inclusion and exclusion criteria were included. The data were analysed by the Friedman and Wilcoxon post-hoc follow-up tests.Results: The statistical analysis showed significant differences in systolic BP (SBP) at 5 minutes after salat, 10 minutes after salat, and 5 minutes vs 10 minutes after salat, both in the treatment and control groups. For the diastolic BP (DBP), a significant difference was found at 5 minutes after salat and 10 minutes after salat in the treatment group, as well as at 10 minutes after salat and 5 minutes after salat vs 10 minutes after salat in the control group. For the pulse variable, a significant difference was found at 5 minutes after salat and 10 minutes after salat in the treatment group, and 5 minutes after salat in the control group.Conclusion: There is a decrease in BP and pulse rate in patients with stage one hypertension after salat.
In this study, a remote photoplethysmography (rPPG) using a near-infrared camera image has been investigated to estimate the pulse rate in a dark environment. We propose a new face segmentation ...method using a skin boundary filter and a pixel-based shape mask filter to improve the rPPG performance. The proposed algorithms were evaluated by applying them to the skin of the whole face and the skin of the lower part of the face. The mean error rates of the estimated pulse rate in the lower part of the face and the whole face area were approximately 2.9% and 9.9%, respectively. Additionally, new dynamic noise cancelation techniques were proposed using a noise cancelation filter, the Kalman filter, and an adaptive filter to remove motion-related noise. Consequently, the mean error rate for 12 subjects drops to 2.0% when the proposed methods are combined. The rPPG signal showed robust results in motion artifact.
