Uneven terrain affects metabolic cost and gait in simulated complex lunar surfaces
In this study, ten healthy subjects (6 male and 4 female) participated in three simulated lunar terrain walking conditions at the NASA Johnson Space Center's planetary 'Rock Yard': (1) flat terrain, (2) flat terrain with obstacles, and (3) mixed terrain. Approach. Energy expenditure and gait were quantified with a wearable metabolic energy expenditure monitoring system and body-worn inertial measurement units (IMUs), respectively. Main results. It was found that participants walking on the mixed terrain, representing the highest workload condition, required significantly higher metabolic costs than in other terrain conditi...
Source: Physiological Measurement - October 5, 2023 Category: Physiology Authors: Kyoung Jae Kim, Alexander Baughman, Patrick Estep, Eric Rivas, Millennia Young, Karina Marshall-Goebel, Andrew Abercromby and Jeffrey Somers Source Type: research
Atrial fibrillation detection with signal decomposition and dilated residual neural network
In this study, we proposed a novel feature extraction method that generates a pseudo QRS complex signal and a pseudo T, P wave signal for each raw ECG signal using a temporal mask built upon R peak detection. Then a novel dilated residual neural network was trained on the decomposed signal. Main results. We evaluated the performance of our method on the dataset of PhysioNet/CinC 2017 Challenge, achieving an average score of 0.843. The method was further tested on MIT-BIH Atrial Fibrillation Database, and an average score of 0.984 was obtained. Significance. Our proposed ECG signal decomposition technique introduces simple ...
Source: Physiological Measurement - October 4, 2023 Category: Physiology Authors: Yicheng Li and Yong Xia Source Type: research
Characterization of cardiovascular and cerebrovascular controls via spectral causality analysis in patients undergoing surgical aortic valve replacement during a three-month follow-up
Objective. Aortic valve stenosis (AVS) induces left ventricular function adaptations and surgical aortic valve replacement (SAVR) restores blood flow profile across aortic valve. Modifications of cardiac hemodynamics induced by AVS and SAVR might alter cardiovascular (CV) and cerebrovascular (CBV) controls. The study aims at characterizing CV and CBV regulations one day before SAVR (PRE), within one week after SAVR (POST), and after a three-month follow-up (POST3) in 73 AVS patients (age: 63.9 ± 12.9 yrs; 48 males, 25 females) from spontaneous fluctuations of heart period (HP), systolic arterial pressure, mean arterial pr...
Source: Physiological Measurement - September 28, 2023 Category: Physiology Authors: Vlasta Bari, Francesca Gelpi, Beatrice Cairo, Martina Anguissola, Sara Pugliese, Beatrice De Maria, Enrico Giuseppe Bertoldo, Valentina Fiolo, Edward Callus, Carlo De Vincentiis, Marianna Volpe, Raffaella Molfetta, Marco Ranucci and Alberto Porta Source Type: research
B3X: a novel efficient algorithm for accurate automated auscultatory blood pressure estimation
This study proposes a relatively simple methodology, named B3X, to estimate SBP and DBP by processing Korotkoff sounds recordings acquired during an auscultatory NIBP measurement. Approach. The beat-by-beat change in morphology of adjacent Korotkoff sounds is evaluated via their cross-correlation. The time series of the beat-by-beat cross-correlation and its first derivative are analyzed to locate the timings of SBP and DBP values. Extensive tests were performed on a public database of 350 annotated measurements, and the performance was evaluated according to the BHS, AAMI/ANSI, and International Organization for Standardi...
Source: Physiological Measurement - September 27, 2023 Category: Physiology Authors: Jessica Centracchio, Davide De Caro, Paolo Bifulco and Emilio Andreozzi Source Type: research
Bio-potential noise of dry printed electrodes: physiology versus the skin-electrode impedance
Objective. To explore noise characteristics and the effect physiological activity has on the link between impedance and noise. Approach. Dry-printed electrodes are emerging as a new and exciting technology for skin electro-physiology. Such electrode arrays offer many advantages including user convenience, quick placement, and high resolution. Here we analyze extensive electro-physiological data recorded from the arm and the face to study and quantify the noise of dry electrodes, and to characterize the link between noise and impedance. In particular, we studied the effect of the physiological state of the subject (e.g. rap...
Source: Physiological Measurement - September 25, 2023 Category: Physiology Authors: Ana Arch é-Núñez, Peter Krebsbach, Bara Levit, Daniel Possti, Aaron Gerston, Thorsten Knoll, Thomas Velten, Chen Bar-Haim, Shani Oz, Shira Klorfeld-Auslender, Gerardo Hernandez-Sosa, Anat Mirelman and Yael Hanein Source Type: research
Threshold distribution of equal states for quantitative amplitude fluctuations
Objective. The distribution of equal states (DES) quantifies amplitude fluctuations in biomedical signals. However, under certain conditions, such as a high resolution of data collection or special signal processing techniques, equal states may be very rare, whereupon the DES fails to measure the amplitude fluctuations. Approach. To address this problem, we develop a novel threshold DES (tDES) that measures the distribution of differential states within a threshold. To evaluate the proposed tDES, we first analyze five sets of synthetic signals generated in different frequency bands. We then analyze sleep electroencephalogr...
Source: Physiological Measurement - September 21, 2023 Category: Physiology Authors: Wenpo Yao, Wenli Yao and Jun Wang Source Type: research
Regurgitation during the fully supported condition of the percutaneous left ventricular assist device
Objective. A percutaneous left ventricular assist device (PLVAD) can be used as a bridge to heart transplantation or as a temporary support for end-stage heart failure. Transvalvularly placed PLVADs may result in aortic regurgitation due to unstable pump position during fully supported operation, which may diminish the pumping effect of forward flow and predispose to complications. Therefore, accurate characterization of aortic regurgitation is essential for proper modeling of heart-pump interactions and validation of control strategies. Approach. In the present study, an improved aortic valve model was used to analyze the...
Source: Physiological Measurement - September 21, 2023 Category: Physiology Authors: Anyun Yin, Biyang Wen, Zijian Cao, Qilian Xie and Ming Dai Source Type: research
Potential limitations of measuring ambulatory activity of part-time wheelchair users: a comparative study of two research grade activity monitors
Objective. Research grade activity monitors such as the StepWatch Activity Monitor (SAM) and Actigraph have been shown to be highly accurate for the assessment of ambulatory activity, but some individuals function in the community using a combination of both walking and wheelchair activity. The purpose of this study was to assess the accuracy of the SAM and Actigraph at not detecting ambulatory activity, during wheelchair activities at two intensity levels. Approach. Two independent cohorts were tested while simultaneously wearing a SAM and Actigraph on the ankle. Group 1 consisted of twelve adults performing a six-minute ...
Source: Physiological Measurement - September 20, 2023 Category: Physiology Authors: Wilshaw Stevens, Fernanda Harlett, Robert L Wimberly and Kirsten Tulchin-Francis Source Type: research
A learnable front-end based efficient channel attention network for heart sound classification
Objective. To enhance the accuracy of heart sound classification, this study aims to overcome the limitations of common models which rely on handcrafted feature extraction. These traditional methods may distort or discard crucial pathological information within heart sounds due to their requirement of tedious parameter settings. Approach. We propose a learnable front-end based Efficient Channel Attention Network (ECA-Net) for heart sound classification. This novel approach optimizes the transformation of waveform-to-spectrogram, enabling adaptive feature extraction from heart sound signals without domain knowledge. The fea...
Source: Physiological Measurement - September 20, 2023 Category: Physiology Authors: Aolei Liu, Sunjie Zhang, Zhe Wang, Yiheng Tang, Xiaoli Zhang and Yongxiong Wang Source Type: research
A wireless physiological parameter monitoring system with a treatment feedback function during neonatal phototherapy
Objective. Neonatal jaundice is a common condition in the early stages of newborns, and phototherapy is a fast, safe and effective method that is used to treat it. However, recent studies have shown that phototherapy may elicit side effects in infants, such as hypothermia, hyperthermia and dehydration. To improve the quality of phototherapy and the prognosis of patients, the changes in neonatal physiological parameters during phototherapy should be monitored to give better feedback to pediatricians or the phototherapy system. However, the current standard of clinical care during neonatal phototherapy with hard-wired device...
Source: Physiological Measurement - September 17, 2023 Category: Physiology Authors: Ziliang He, Benjin Zhang, Jing Zhang, Zhenghua Xiao, Ling He and Gang Yang Source Type: research
Non-contact quantification of aortic stenosis and mitral regurgitation using carotid waveforms from skin displacements
We present a clinical study of the system in patients (n = 27) with no underlying condition, aortic stenosis (AS), or mitral regurgitation (MR). Main results. Displacement waveforms were compared to aortic catheter pressures in the same patients. The morphologies of the pressure and displacement waveforms were found to be similar, and pulse wave analysis metrics, such as our modified reflection indices (RI) and waveform duration proportions, showed no significant differences. Compared with the control group, AS patients displayed a greater proportion of time to peak (p = 0.026 and p = 0.047 for catheter and displacement, r...
Source: Physiological Measurement - September 10, 2023 Category: Physiology Authors: Prashanna Khwaounjoo, Alexander W Dixon, Amir HajiRassouliha, Emily J Lam Po Tang, Mark W I Webster, Andrew J Taberner, Poul M F Nielsen, Martyn P Nash and Yusuf O Cakmak Source Type: research
Comment on ‘Limitations in evaluating COVID-19 protective face masks using open circuit spirometry systems: respiratory measurement mask introduces bias in breathing pressure and perceived respiratory effort’
We comment on the paper by Seibt and coworkers (Seibt et al 2023) which investigates whether wearing an additional respiratory measurement mask during open-circuit spirometry assessments (respirometry mask) shows any effect on breathing pressure and perceived respiratory effort when wearing protective face masks commonly worn during the COVID-19 pandemic. (Source: Physiological Measurement)
Source: Physiological Measurement - August 31, 2023 Category: Physiology Authors: Eike Maximilian Marek, Vera van Kampen, Birger Jettkant, Frank Hoffmeyer and J ürgen Bünger Source Type: research
Comment on 'Limitations in evaluating COVID-19 protective face masks using open circuit spirometry systems: respiratory measurement mask introduces bias in breathing pressure and perceived respiratory effort'
We comment on the paper by Seibt and coworkers (Seibt et al 2023) which investigates whether wearing an additional respiratory measurement mask during open-circuit spirometry assessments (respirometry mask) shows any effect on breathing pressure and perceived respiratory effort when wearing protective face masks commonly worn during the COVID-19 pandemic. (Source: Physiological Measurement)
Source: Physiological Measurement - August 31, 2023 Category: Physiology Authors: Eike Maximilian Marek, Vera van Kampen, Birger Jettkant, Frank Hoffmeyer and J ürgen Bünger Source Type: research
Fully convolutional neural network and PPG signal for arterial blood pressure waveform estimation
Objective. The quality of the arterial blood pressure (ABP) waveform is crucial for predicting the value of blood pressure. The ABP waveform is predicted through experiments, and then Systolic blood pressure (SBP), Diastolic blood pressure, (DBP), and Mean arterial pressure (MAP) information are estimated from the ABP waveform. Approach. To ensure the quality of the predicted ABP waveform, this paper carefully designs the network structure, input signal, loss function, and structural parameters. A fully convolutional neural network (CNN) MultiResUNet3+ is used as the core architecture of ABP-MultiNet3+. In addition to perf...
Source: Physiological Measurement - August 31, 2023 Category: Physiology Authors: Yongan Zhou, Zhi Tan, Yuhong Liu and Haibo Cheng Source Type: research
Validity and reliability of a commercial wearable sensor system for measuring spatiotemporal gait parameters in a post-stroke population: the effects of walking speed and asymmetry
This study supports the general use of Opal wearable sensors to obtain quantitative meas ures of post-stroke gait impairment. These measures should be interpreted cautiously for individuals with moderate-severe asymmetry or walking speeds slower than 0.80 m s−1. (Source: Physiological Measurement)
Source: Physiological Measurement - August 29, 2023 Category: Physiology Authors: Francesco Lanotte, Sung Yul Shin, Megan K O'Brien and Arun Jayaraman Source Type: research
