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Physiological Measurement

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https://www.readbyqxmd.com/read/28107205/comparison-of-linear-and-non-linear-models-for-predicting-energy-expenditure-from-raw-accelerometer-data
#1
Alexander H K Montoye, Munni Begum, Zachary Henning, Karin A Pfeiffer
This study had three purposes, all related to evaluating energy expenditure (EE) prediction accuracy from body-worn accelerometers: (1) compare linear regression to linear mixed models, (2) compare linear models to artificial neural network models, and (3) compare accuracy of accelerometers placed on the hip, thigh, and wrists. Forty individuals performed 13 activities in a 90 min semi-structured, laboratory-based protocol. Participants wore accelerometers on the right hip, right thigh, and both wrists and a portable metabolic analyzer (EE criterion)...
January 20, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28107204/non-invasive-blood-glucose-detection-system-based-on-conservation-of-energy-method
#2
Yang Zhang, Jian-Ming Zhu, Yong-Bo Liang, Hong-Bo Chen, Shi-Min Yin, Zhen-Cheng Chen
The most common method used for minimizing the occurrence of diabetes complications is frequent glucose testing to adjust the insulin dose. However, using blood glucose (BG) meters presents a risk of infection. It is of great importance to develop non-invasive BG detection techniques. To realize high-accuracy, low-cost and continuous glucose monitoring, we have developed a non-invasive BG detection system using a mixed signal processor 430 (MSP430) microcontroller. This method is based on the combination of the conservation-of-energy method with a sensor integration module, which collects physiological parameters, such as the blood oxygen saturation (SPO2), blood flow velocity and heart rate...
January 20, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099172/decrease-of-muscle-fiber-conduction-velocity-correlates-with-strength-loss-after-an-endurance-run
#3
Gennaro Boccia, Davide Dardanello, Cantor Tarperi, Valeria Rosso, Luca Festa, Antonio La Torre, Barbara Pellegrini, Federico Schena, Alberto Rainoldi
Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity (CV) changes induced by an endurance run. The day before and immediately after a half-marathon run (21.097 km) 11 amateur runners performed maximum voluntary contractions (MVCs) of knee extensor muscles. During the MVC, multichannel EMG was recorded from the vastus lateralis and EMG amplitude and CV were calculated...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099169/a-comparison-of-stimulus-presentation-methods-in-temporal-discrimination-testing
#4
Eavan M Mc Govern, John S Butler, Ines Beiser, Laura Williams, Brendan Quinlivan, Shruti Narasiham, Rebecca Beck, Sean O'Riordan, Richard B Reilly, Michael Hutchinson
The temporal discrimination threshold (TDT) is the shortest time interval at which an individual detects two stimuli to be asynchronous (normal  =  30-50 ms). It has been shown to be abnormal in patients with disorders affecting the basal ganglia including adult onset idiopathic focal dystonia (AOIFD). Up to 97% of patients have an abnormal TDT with age- and sex-related penetrance in unaffected relatives, demonstrating an autosomal dominant inheritance pattern. These findings support the use of the TDT as a pre-clinical biomarker for AOIFD...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099168/a-non-invasive-approach-to-investigation-of-ventricular-blood-pressure-using-cardiac-sound-features
#5
Hong Tang, Jinghui Zhang, Huaming Chen, Ashok Mondal, Yongwan Park
Heart sounds (HSs) are produced by the interaction of the heart valves, great vessels, and heart wall with blood flow. Previous researchers have demonstrated that blood pressure can be predicted by exploring the features of cardiac sounds. These features include the amplitude of the HSs, the ratio of the amplitude, the systolic time interval, and the spectrum of the HSs. A single feature or combinations of several features have been used for prediction of blood pressure with moderate accuracy. Experiments were conducted with three beagles under various levels of blood pressure induced by different doses of epinephrine...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099167/non-invasive-measurement-of-volume-time-curves-in-patients-with-mitral-regurgitation-and-in-healthy-volunteers-using-a-new-operator-independent-screening-tool
#6
Maurits K Konings, Rosemarijn Jansen, Laurens P Bosman, Rienk Rienks, Steven A J Chamuleau, Frank E Rademakers, Maarten J Cramer
Left ventricular volume-time curves (VTCs) provide hemodynamic data, and may help clinical decision making. The generation of VTCs using echocardiography, however, is time-consuming and prone to inter-operator variability. In this study, we used a new non-invasive, operator-independent technique, the hemodynamic cardiac profiler (HCP), to generate VTCs. The HCP, which uses a low-intensity, patient-safe, high-frequency applied AC current, and 12 standard ECG electrodes attached on the thorax in a pre-defined pattern, was applied to five young healthy volunteers, five older healthy volunteers, and five patients with severe mitral regurgitation...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099166/despiking-seeg-signals-reveals-dynamics-of-gamma-band-preictal-activity
#7
Nawel Jmail, Martine Gavaret, F Bartolomei, Christian-G Bénar
Interictal epileptiform discharges, or 'interictal spikes', are the hallmark of epilepsy. Still, there is growing evidence that oscillatory activity-whether in the gamma band (30-120 Hz) or at higher frequencies is another important marker of hyperexcitable tissues. A major difficulty arises from the fact that interictal spikes and oscillations overlap in the frequency domain. This hampers the correct delineation of the cortex producing pathological oscillations by simple filtering. Here, we propose a nonlinear technique for fitting the spike waveform in order to remove it, resulting in a 'despiked' signal...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099163/adapting-smartphone-based-photoplethysmograpy-to-suboptimal-scenarios
#8
Augusto Garcia-Agundez, Tim Dutz, Stefan Goebel
Photoplethysmography (PPG) is an optical technique used to measure the heart rate (HR) and other cardiovascular variables by analyzing volume changes in the microvascular bed of tissue. At the moment, smartphone users can already measure their HR using PPG applications that use the smartphone's built-in camera. However, available applications are unreliable when artifacts are present, such as those caused by movement, finger pressure, or ambient light changes. This contribution aims to analyze the limitations of a smartphone-based PPG algorithm capable of measuring N-N intervals when such artifacts are present by comparing it to a 2-lead electrocardiography (ECG)...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099162/thermography-based-blood-flow-imaging-in-human-skin-of-the-hands-and-feet-a-spectral-filtering-approach
#9
A A Sagaidachnyi, A V Fomin, D A Usanov, A V Skripal
The determination of the relationship between skin blood flow and skin temperature dynamics is the main problem in thermography-based blood flow imaging. Oscillations in skin blood flow are the source of thermal waves propagating from micro-vessels toward the skin's surface, as assumed in this study. This hypothesis allows us to use equations for the attenuation and dispersion of thermal waves for converting the temperature signal into the blood flow signal, and vice versa. We developed a spectral filtering approach (SFA), which is a new technique for thermography-based blood flow imaging...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099161/menstrual-cycle-and-the-temporal-discrimination-threshold
#10
Eavan M Mc Govern, Emer O'Connor, Ines Beiser, Laura Williams, John S Butler, Brendan Quinlivan, Shruti Narasiham, Rebecca Beck, Richard B Reilly, Sean O'Riordan, Michael Hutchinson
The temporal discrimination threshold (TDT) is a proposed pre-clinical biomarker (endophenotype) for adult onset isolated focal dystonia (AOIFD). Age- and sex-related effects on temporal discrimination demonstrate that women, before the age of 40 years, have faster temporal discrimination than men but their TDTs worsen with age at almost three times the rate of men. Thus after 40 years the TDT in women is progressively worse than in men. AOIFD is an increasingly female-predominant disorder after the age of 40; it is not clear whether this age-related sexually-dimorphic difference observed for both the TDT and sex ratio at disease onset in AOIFD is a hormonal or chromosomal effect...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099160/phase-shift-between-respiratory-oscillations-in-cerebral-blood-flow-velocity-and-arterial-blood-pressure
#11
Agnieszka Uryga, Michał M Placek, Paweł Wachel, Tomasz Szczepański, Marek Czosnyka, Magdalena Kasprowicz
We aim to investigate whether phase shift between respiratory oscillations in cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) is associated with changes in cerebral autoregulation (CA) or reflects the mechano-elastic properties of the cerebrovascular bed. The relationships between respiratory phase shift and slow wave phase shift versus cerebrovascular time constant (the product of cerebrovascular resistance and compliance) and the index of CA (Mx) were analyzed during breathing at 6, 10, and 15 breaths min(-1) in 39 volunteers...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099159/reducing-false-arrhythmia-alarm-rates-using-robust-heart-rate-estimation-and-cost-sensitive-support-vector-machines
#12
Qiang Zhang, Xianxiang Chen, Zhen Fang, Qingyuan Zhan, Ting Yang, Shanhong Xia
To lessen the rate of false critical arrhythmia alarms, we used robust heart rate estimation and cost-sensitive support vector machines. The PhysioNet MIMIC II database and the 2015 PhysioNet/CinC Challenge public database were used as the training dataset; the 2015 Challenge hidden dataset was for testing. Each record had an alarm labeled with asystole, extreme bradycardia, extreme tachycardia, ventricular tachycardia or ventricular flutter/fibrillation. Before alarm onsets, 300 s multimodal data was provided, including electrocardiogram, arterial blood pressure and/or photoplethysmogram...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28079528/assessing-the-evolution-of-redundancy-synergy-of-spontaneous-variability-regulation-with-age
#13
Alberto Porta, Vlasta Bari, Beatrice De Maria, Natália Maria Perseguini, Juliana Milan, Patricia Rehder-Santos, Vinícius Minatel, Anielle Takahashi, Aparecida Catai
We exploited a model-based Wiener-Granger causality method in the information domain for the evaluation of the transfer entropy (TE) and interaction TE (ITE), the latter taken as a measure of the net balance between redundancy and synergy, to describe the interactions between the spontaneous variability of heart period (HP) and systolic arterial pressure (SAP) and the effect of respiration (R) on both variables. Cardiac control was typified via the genuine TE from SAP to HP, that from R to HP, and the ITE from SAP and R to HP, while vascular control was characterized via the genuine TE from HP to SAP, that from R to SAP, and the ITE from HP and R to SAP...
January 12, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28079524/spatial-heterogeneity-in-the-time-and-frequency-properties-of-skin-perfusion
#14
Michele Sorelli, Zlatka Stoyneva, Irina Mizeva, Leonardo Bocchi
Pathological alterations of the microcirculatory system can be identified by measuring the temporal and spectral properties of Laser Doppler Flowmetry (LDF) signals acquired on the skin, and their changes following physiological stimulation. A wide range of stimulation protocols and measurement locations are observed in literature. Researchers often use non-invasive stimulation techniques, such as post-occlusive hyperaemia, cold tests, and local heating. As concerns the stimulation/recording sites, the forearm, fingers, and toes are typically selected to conduct microcirculation studies...
January 12, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28067216/age-and-sex-influence-on-bone-and-blood-lead-concentrations-in-a-cohort-of-the-general-population-living-in-toronto
#15
Sepideh Behinaein, David Chettle, Mandy Fisher, William Manton, Leonora Marro, David Fleming, Norm Healey, Mike Inskip, Tye Arbuckle, Fiona McNeill
A 109Cd K X-ray fluorescence (KXRF) measurement system was used from 2009 to 2011 in a study that measured the bone lead (Pb) concentration of 263 environmentally exposed individuals residing in Toronto, Ontario, Canada. Tibia (cortical bone) and calcaneus (trabecular bone) lead contents were measured in 134 males and 129 females between 1 and 82 years of age. Whole blood Pb concentration was measured by TIMS (thermal ionization mass spectrometer). Tibia (Ti) and calcaneus (Cal) Pb were examined versus the age of participants, taking into account uncertainties in bone Pb measurement values...
January 9, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28067212/estimation-of-the-qt-rr-relation-trade-off-between-goodness-of-fit-and-extrapolation-accuracy
#16
Alain Vinet, Bruno Dubé, Réginald Nadeau, Omar Mahiddine, Vincent Jacquemet
Correction of the QT interval in the ECG for changes in heart rate (RR interval) is needed to compare groups of patients and assess the risk of sudden cardiac death. The QTc represents the QT interval at 60 bpm, although most patients typically have a faster heart rate, thus requiring extrapolation of the QT-RR relationship. This paper investigates the ability of QT-RR models with increasing number of parameters to fit beat-to-beat variations in the QT interval and provide a reliable estimate of the QTc. One-, two- and three-parameter functions generalising the Bazett and Fridericia formulas were used in combination with hysteresis reduction (memory) obtained by time-averaging the history of RR intervals with exponentially-decaying weights...
January 9, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28060775/customized-portable-neutron-activation-analysis-system-to-quantify-manganese-mn-in-bone-in-vivo
#17
Yingzi Liu, Farshad Mostafaei, Daniel Sowers, Ming-Jung Hsieh, Wei Zheng, Linda Nie
In the US alone, millions of workers, including over 300,000 welders, are at high risk of occupational manganese (Mn) exposure. Those who have been chronically exposed to excessive amount of Mn can develop severe neurological disorders similar, but not identical, to the idiopathic Parkinson's disease. One challenge to identify the health effects of Mn exposure is to find a reliable biomarker for exposure assessment, especially for long-term cumulative exposure. Mn's long biological half-life as well as its relatively high concentration in bone makes bone Mn (BnMn) a potentially valuable biomarker for Mn exposure...
January 6, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28055987/heart-beat-classification-from-single-lead-ecg-using-the-synchrosqueezing-transform
#18
Christophe L Herry, Martin Frasch, Andrew Je Seely, Hau-Tieng Wu
The processing of ECG signal provides a wealth of information on cardiac function and overall cardiovascular health. While multi-lead ECG recordings are often necessary for a proper assessment of cardiac rhythms, they are not always available or practical, for example in fetal ECG applications. Moreover, a wide range of small non-obtrusive single-lead ECG ambulatory monitoring devices are now available, from which heart rate variability (HRV) and other health-related metrics are derived. Proper beat detection and classification of abnormal rhythms is important for reliable HRV assessment and can be challenging in single-lead ECG monitoring devices...
January 5, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28055986/robust-heart-rate-estimation-using-wrist-type-photoplethysmographic-signals-during-physical-exercise-an-approach-based-on-adaptive-filtering
#19
Sibylle Fallet, Jean-Marc Vesin
Photoplethysmographic (PPG) signals are easily corrupted by motion artifacts when the subjects perform physical exercise. This paper introduces a two-step processing scheme to estimate heart rate (HR) from wrist-type PPG signals strongly corrupted by motion artifacts. Adaptive noise cancellation, using normalized least-mean-square algorithm, is first performed to attenuate motion artifacts and reconstruct multiple PPG waveforms from different combinations of corrupted PPG waveforms and accelerometer data. An adaptive band-pass filter is then used to track the common instantaneous frequency component (i...
January 5, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28055983/matching-the-reaction-diffusion-simulation-to-dynamic-18-f-fmiso-pet-measurements-in-tumors-extension-to-a-flow-limited-oxygen-dependent-model
#20
Kuangyu Shi, Christine Bayer, Florian C Gaertner, Sabrina T Astner, Jan J Wilkens, Fridtjof Nüsslin, Peter Vaupel, Sibylle I Ziegler
Positron-emission tomography (PET) with hypoxia specific tracers provides a noninvasive method to assess the tumor oxygenation status. Reaction-diffusion models have advantages in revealing the quantitative relation between in vivo imaging and the tumor microenvironment. However, there is no quantitative comparison of the simulation results with the real PET measurements yet. The lack of experimental support hampers further applications of computational simulation models. This study aims to compare the simulation results with a preclinical [(18)F]FMISO PET study and to optimize the reaction-diffusion model accordingly...
January 5, 2017: Physiological Measurement
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