Evaluation of calibrated and uncalibrated optical imaging approaches for relative cerebral oxygen metabolism measurements in awake mice
This study provides a quantitative comparison of these scenarios to evaluate trade-offs that can be vital to the design of blood oxygenation sensitive imaging experiments for rCMRO2 calculation. (Source: Physiological Measurement)
Source: Physiological Measurement - April 23, 2024 Category: Physiology Authors: A E Toader, M Fukuda and A L Vazquez Source Type: research
TSS-ConvNet for electrical impedance tomography image reconstruction
The objective of this study was to propose a novel data-driven method for solving ill-posed inverse problems, particularly in certain conditions such as time-difference electrical impedance tomography for detecting the location and size of bubbles inside a pipe. Approach. We introduced a new layer architecture composed of three paths: spatial, spectral, and truncated spectral paths. The spatial path processes information locally, whereas the spectral and truncated spectral paths provide the network with a global receptive field. This unique architecture helps eliminate the ill-posedness and nonlinearity inherent in the inv...
Source: Physiological Measurement - April 17, 2024 Category: Physiology Authors: Ayman A Ameen, Achim Sack and Thorsten P öschel Source Type: research
Photoplethysmography based atrial fibrillation detection: a continually growing field
Objective. Atrial fibrillation (AF) is a prevalent cardiac arrhythmia associated with significant health ramifications, including an elevated susceptibility to ischemic stroke, heart disease, and heightened mortality. Photoplethysmography (PPG) has emerged as a promising technology for continuous AF monitoring for its cost-effectiveness and widespread integration into wearable devices. Our team previously conducted an exhaustive review on PPG-based AF detection before June 2019. However, since then, more advanced technologies have emerged in this field. Approach. This paper offers a comprehensive review of the latest advan...
Source: Physiological Measurement - April 16, 2024 Category: Physiology Authors: Cheng Ding, Ran Xiao, Weijia Wang, Elizabeth Holdsworth and Xiao Hu Source Type: research
Sensitivity volume as figure-of-merit for maximizing data importance in electrical impedance tomography
Objective. Electrical impedance tomography (EIT) is a noninvasive imaging method whereby electrical measurements on the periphery of a heterogeneous conductor are inverted to map its internal conductivity. The EIT method proposed here aims to improve computational speed and noise tolerance by introducing sensitivity volume as a figure-of-merit for comparing EIT measurement protocols. Approach. Each measurement is shown to correspond to a sensitivity vector in model space, such that the set of measurements, in turn, corresponds to a set of vectors that subtend a sensitivity volume in model space. A maximal sensitivity volum...
Source: Physiological Measurement - April 15, 2024 Category: Physiology Authors: Claire C Onsager, Chulin Wang, Charles Costakis, Can C Aygen, Lauren Lang, Suzan van der Lee and Matthew A Grayson Source Type: research
Visualizing pursed lips breathing of patients with chronic obstructive pulmonary disease through evaluation of global and regional ventilation using electrical impedance tomography
This study aims to explore the possibility of using electrical impedance tomography (EIT) to assess pursed lips breathing (PLB) performance of patients with chronic obstructive pulmonary disease (COPD). Methods. 32 patients with COPD were assigned equally to either the conventional group or the EIT guided group. All patients were taught to perform PLB by a physiotherapist without EIT in the conventional group or with EIT in the EIT guided group for 10 min. The ventilation of all patients in the final test were continuously monitored using EIT and the PLB performances were rated by another physiotherapist before and after r...
Source: Physiological Measurement - April 15, 2024 Category: Physiology Authors: Lin Yang, Zhijun Gao, Xinsheng Cao, Chunchen Wang, Hang Wang, Jing Dai, Yang Liu, Yilong Qin, Meng Dai, Binghua Zhang, Ke Zhao and Zhanqi Zhao Source Type: research
Harmonization of three different accelerometers to classify the 24 h activity cycle
Increasing interest in measuring key components of the 24 h activity cycle (24-HAC) [sleep, sedentary behavior (SED), light physical activity (LPA), and moderate to vigorous physical activity (MVPA)] has led to a need for better methods. Single wrist-worn accelerometers and different self-report instruments can assess the 24-HAC but may not accurately classify time spent in the different components or be subject to recall errors. Objective. To overcome these limitations, the current study harmonized output from multiple complimentary research grade accelerometers and assessed the feasibility and logistical challenges of th...
Source: Physiological Measurement - April 10, 2024 Category: Physiology Authors: Benjamin D Boudreaux, Ginny M Frederick, Patrick J O ’Connor, Ellen M Evans and Michael D Schmidt Source Type: research
Blood flow restriction attenuates surface mechanomyography lateral and longitudinal, but not transverse oscillations during fatiguing exercise
Objective. Surface mechanomyography (sMMG) can measure oscillations of the activated muscle fibers in three axes (i.e. X, Y, and Z-axes) and has been used to describe motor unit activation patterns (X-axis). The application of blood flow restriction (BFR) is common in exercise studies, but the cuff may restrict muscle fiber oscillations. Therefore, the purpose of this investigation was to examine the acute effects of submaximal, fatiguing exercise with and without BFR on sMMG amplitude in the X, Y, and Z-axes among female participants. Approach. Sixteen females (21 ± 1 years) performed two separate exercise bouts to volit...
Source: Physiological Measurement - April 8, 2024 Category: Physiology Authors: Ethan C Hill, Chris E Proppe, Paola M Rivera, Sean M Lubiak, David H Gonzalez Rojas, John E Lawson, Hwan Choi, Hansen Mansy and Joshua L Keller Source Type: research
pyPPG: a Python toolbox for comprehensive photoplethysmography signal analysis
Objective. Photoplethysmography is a non-invasive optical technique that measures changes in blood volume within tissues. It is commonly and being increasingly used for a variety of research and clinical applications to assess vascular dynamics and physiological parameters. Yet, contrary to heart rate variability measures, a field which has seen the development of stable standards and advanced toolboxes and software, no such standards and limited open tools exist for continuous photoplethysmogram (PPG) analysis. Consequently, the primary objective of this research was to identify, standardize, implement and validate key di...
Source: Physiological Measurement - April 7, 2024 Category: Physiology Authors: M árton Á Goda, Peter H Charlton and Joachim A Behar Source Type: research
Unsupervised ensembling of multiple software sensors with phase synchronization: a robust approach for electrocardiogram-derived respiration
Conclusion. The sync-ensembled EDR provides robust respiratory information from electrocardiogram. Significance. Phase synchronization is not only theoretically rigorous but also practical to design a robust EDR. (Source: Physiological Measurement)
Source: Physiological Measurement - April 2, 2024 Category: Physiology Authors: Jacob McErlean, John Malik, Yu-Ting Lin, Ronen Talmon and Hau-Tieng Wu Source Type: research
Respiratory gating improves correlation between pulse wave transit time and pulmonary artery pressure in experimental pulmonary hypertension
Objective. Since pulse wave transit time (PWTT) shortens as pulmonary artery pressure (PAP) increases it was suggested as a potential non-invasive surrogate for PAP. The state of tidal lung filling is also known to affect PWTT independently of PAP. The aim of this retrospective analysis was to test whether respiratory gating improved the correlation coefficient between PWTT and PAP. Approach. In each one of five anesthetized and mechanically ventilated pigs two high-fidelity pressure catheters were placed, one directly behind the pulmonary valve, and the second one in a distal branch of the pulmonary artery. PAP was raised...
Source: Physiological Measurement - March 29, 2024 Category: Physiology Authors: Fabian Mueller-Graf, Paul Frenkel, Jonas Merz, Susanne Reuter, Brigitte Vollmar, Gerardo Tusman, Sven Pulletz, Stephan H. B öhm, Amelie Zitzmann, Daniel A Reuter and Andy Adler Source Type: research
Cerebral asymmetry representation learning-based deep subdomain adaptation network for electroencephalogram-based emotion recognition
Objective. Extracting discriminative spatial information from multiple electrodes is a crucial and challenging problem for electroencephalogram (EEG)-based emotion recognition. Additionally, the domain shift caused by the individual differences degrades the performance of cross-subject EEG classification. Approach. To deal with the above problems, we propose the cerebral asymmetry representation learning-based deep subdomain adaptation network (CARL-DSAN) to enhance cross-subject EEG-based emotion recognition. Specifically, the CARL module is inspired by the neuroscience findings that asymmetrical activations of the left a...
Source: Physiological Measurement - March 26, 2024 Category: Physiology Authors: Zhe Wang, Yongxiong Wang, Xin Wan and Yiheng Tang Source Type: research
Maximum a posteriori detection of heartbeats from a chest-worn accelerometer
Objective. Unobtrusive long-term monitoring of cardiac parameters is important in a wide variety of clinical applications, such as the assesment of acute illness severity and unobtrusive sleep monitoring. Here we determined the accuracy and robustness of heartbeat detection by an accelerometer worn on the chest. Approach. We performed overnight recordings in 147 individuals (69 female, 78 male) referred to two sleep centers. Two methods for heartbeat detection in the acceleration signal were compared: one previously described approach, based on local periodicity, and a novel extended method incorporating maximum aposterior...
Source: Physiological Measurement - March 21, 2024 Category: Physiology Authors: Fons Schipper, Ruud J G van Sloun, Angela Grassi, Jan Brouwer, Fokke van Meulen, Sebastiaan Overeem and Pedro Fonseca Source Type: research
Validation of three-dimensional thoracic electrical impedance tomography of horses during normal and increased tidal volumes
Objective. Data from two-plane electrical impedance tomography (EIT) can be reconstructed into various slices of functional lung images, allowing for more complete visualisation and assessment of lung physiology in health and disease. The aim of this study was to confirm the ability of 3D EIT to visualise normal lung anatomy and physiology at rest and during increased ventilation (represented by rebreathing). Approach. Two-plane EIT data, using two electrode planes 20 cm apart, were collected in 20 standing sedate horses at baseline (resting) conditions, and during rebreathing. EIT data were reconstructed into 3D EIT where...
Source: Physiological Measurement - March 21, 2024 Category: Physiology Authors: David P Byrne, Nicole Studer, Cristy Secombe, Alexander Cieslewicz, Giselle Hosgood, Anthea Raisis, Andy Adler and Martina Mosing Source Type: research
Algorithmic detection of sleep-disordered breathing using respiratory signals: a systematic review
Conclusions. Multiple detection algorithms have been widely applied for SDB detection, and their accuracy is c losely related to factors such as signal source, signal processing, feature selection, and model selection. (Source: Physiological Measurement)
Source: Physiological Measurement - March 21, 2024 Category: Physiology Authors: Liqing Yang, Zhimei Ding, Jiangjie Zhou, Siyuan Zhang, Qi Wang, Kaige Zheng, Xing Wang and Lin Chen Source Type: research
Remote photoplethysmography based on reflected light angle estimation
Objective. In previous studies, the factors affecting the accuracy of imaging photoplethysmography (iPPG) heart rate (HR) measurement have been focused on the light intensity, facial reflection angle, and motion artifacts. However, the factor of specularly reflected light has not been studied in detail. We explored the effect of specularly reflected light on the accuracy of HR estimation and proposed an estimation method for the direction of specularly radiated light. Approach. To study the HR measurement accuracy influenced by specularly reflected light, we control the component of specularly reflected light by controllin...
Source: Physiological Measurement - March 20, 2024 Category: Physiology Authors: Xuanhe Fan, Fangwu Liu, Jinjin Zhang, Tong Gao, Ziyang Fan, Zhijie Huang, Wei Xue and JingJing Zhang Source Type: research
