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Physiological Measurement

Zachary A Vesoulis, Steve M Liao, Amit M Mathur
Post-resuscitation reperfusion following hypoxic-ischemia (HIE) is associated with secondary brain injury in neonates. 
 Objective: To quantify the association between perfusion exceeding autoregulatory limits and brain injury.
 Methods: Continuous mean arterial blood pressure (MABP) and cerebral near-infrared spectroscopy (NIRS) data were prospectively collected from infants with HIE. Cerebral oximetry index (COx) was calculated as a moving correlation coefficient between MABP and NIRS...
October 1, 2018: Physiological Measurement
Timo Leppänen, Antti Kulkas, Arie Oksenberg, Brett Duce, Esa Mervaala, Juha Töyräs
<b>Objective: </b>In obstructive sleep apnea (OSA) breathing cessations are often followed by arousals leading into sleep fragmentation and thus, impaired sleep quality. Arousals and fragmented sleep are also related to detrimental cardiovascular events. The key index for OSA diagnosis (<i>i.e.</i> apnea-hypopnea index) attributes equal diagnostic value to apneas and hypopneas despite associated arousals and desaturations may be very different. Thus, considering the severity of consequences of apneas and hypopneas could enhance the estimation of OSA severity...
September 25, 2018: Physiological Measurement
Daniel Álvarez, Andrea Crespo, Fernado Vaquerizo-Villar, Gonzalo Cesar Gutierrez-Tobal, Ana Cerezo-Hernández, Verónica Barroso-García, J Mark Ansermino, Guy A Dumont, Roberto Hornero, Felix Del Campo, Ainara Garde
OBJECTIVE: This study is aimed at assessing symbolic dynamics as a reliable technique to characterise complex fluctuations of portable oximetry in the context of automated detection of childhood obstructive sleep apnoea-hypopnoea syndrome (OSAHS). APPROACH: Nocturnal oximetry signals from 142 children with suspected OSAHS were acquired using the Phone Oximeter: a portable device that integrates a pulse oximeter with a smartphone. An apnoea-hypopnoea index (AHI) ≥5 events/h from simultaneous in-lab polysomnography was used to confirm moderate-to-severe childhood OSAHS...
September 19, 2018: Physiological Measurement
Zachary W Bell, Scott J Dankel, Kevin T Mattocks, Samuel L Buckner, Matthew B Jessee, J Grant Mouser, Takashi Abe, Jeremy P Loenneke
OBJECTIVE: To determine whether the perceived tightness scale could be used to set sub-occlusive blood flow restriction pressures. A secondary aim was to determine variables that may impact individual ratings. APPROACH: One hundred and twenty participants completed three separate conditions in one limb within the upper and lower body. Participants were asked to rate their perceived tightness for two of the three conditions, regarded as moderate pressure without pain (7/10) and intense pressure with pain (10/10)...
September 13, 2018: Physiological Measurement
Sandra Neumann, Froso Sophocleous, Matthew D Kobetić, Emma C Hart, Angus K Nightingale, Kim H Parker, Mark K Hamilton, Giovanni Biglino
 Hypertension is associated with reduced cerebral blood flow, but it is not known how this impacts on wave dynamics or potentially relates to arterial morphology. Given the location of the internal carotid artery (ICA) and risks associated with invasive measurements, wave dynamics in this artery have not been extensively assessed in vivo. This study explores the feasibility of studying wave dynamics in the internal carotid artery non-invasively. 
 Normotensive, uncontrolled and controlled hypertensive participants were recruited (daytime ambulatory blood pressure <135/85mmHg and >135/85mmHg, respectively; n=38)...
September 7, 2018: Physiological Measurement
N Di Lascio, V Gemignani, E Bianchini, R M Bruno, L Ghiadoni, F Faita
OBJECTIVE: Recently great attention has been paid to innovative cardiovascular biomarkers obtained from wave separation (WS), wave intensity (WI) and reservoir-wave (RW) theories. All these approaches share a requirement for pressure information. The aim of this study was to evaluate differences in WS-, WI- and RW-derived parameters obtained achieving pressure waveforms in different ways. APPROACH: Twenty-two individuals (49  ±  17 years, 59% males) were examined...
November 6, 2018: Physiological Measurement
Kentaro Chino, Hideyuki Takahashi
OBJECTIVE: To examine the influence of pennation angle on measurement of shear wave elastography, this study utilised the propagation view mode that can reveal shear wave propagation in human pennate muscle in vivo. APPROACH: The validity of the propagation view mode was qualitatively confirmed by observation of shear wave propagation in tissue-mimicking phantoms. Shear wave velocity of the medial gastrocnemius (MG) was evaluated in 15 healthy males. By changing the placement of the ultrasound probe on the skin surface, shear wave propagation in the MG was changed: shear waves propagated along the MG fascicles (horizontal condition) and across the fascicles (oblique condition)...
November 6, 2018: Physiological Measurement
Emerson Keenan, Chandan Kumar Karmakar, Marimuthu Palaniswami
OBJECTIVE: Non-invasive fetal electrocardiography (NI-FECG) shows promise for capturing novel physiological information that may indicate signs of fetal distress. However, significant deterioration in NI-FECG signal quality occurs during the presence of a highly non-conductive layer known as vernix caseosa which forms on the fetal body surface beginning in approximately the 28th week of gestation. This work investigates asymmetric modeling of vernix caseosa and other maternal-fetal tissues in accordance with clinical observations and assesses their impacts for NI-FECG signal processing...
November 1, 2018: Physiological Measurement
Jasmin Imsirovic, Erzsébet Bartolák-Suki, Samer Bou Jawde, Harikrishnan Parameswaran, Béla Suki
Vascular smooth muscle cells respond to mechanical stretch by reorganizing their cytoskeletal and contractile elements. Recently, we showed that contractile forces in rat aorta rings were maintained when the rings were exposed to 4 h of physiological variability in cycle-by-cycle strain, called variable stretch (VS), mimicking beat-to-beat blood pressure variability. Contractility, however, was reduced when the aorta was exposed to monotonous stretch (MS) with an amplitude equal to the mean peak strain of VS...
October 30, 2018: Physiological Measurement
Willian da Silva, Álvaro S Machado, Mauren A Souza, Marcos R Kunzler, Jose I Priego-Quesada, Felipe P Carpes
OBJECTIVE: Measurement of skin temperature using infrared thermography has become popular in sports, and has been proposed as an indicator of exercise-induced muscle damage after exercise. However, the relationship between skin temperature and exercise-induced muscle damage is still unclear. Here we set out to investigate the relationship between skin temperature and exercise-induced muscle damage. APPROACH: Twenty untrained participants completed a protocol of exercise for calf muscles...
October 30, 2018: Physiological Measurement
Weixuan Chen, Javier Hernandez, Rosalind W Picard
OBJECTIVE: Non-contact physiological measurement is a growing research area that allows capturing vital signs such as heart rate (HR) and breathing rate (BR) comfortably and unobtrusively with remote devices. However, most of the approaches work only in bright environments in which subtle photoplethysmographic and ballistocardiographic signals can be easily analyzed and/or require expensive and custom hardware to perform the measurements. APPROACH: This work introduces a low-cost method to measure subtle motions associated with the carotid pulse and breathing movement from the neck using near-infrared (NIR) video imaging...
October 30, 2018: Physiological Measurement
Manasi Nandi, Jenny Venton, Philip J Aston
Current arterial pulse monitoring systems capture data at high frequencies (100-1000 Hz). However, they typically report averaged or low frequency summary data such as heart rate and systolic, mean and diastolic blood pressure. In doing so, a potential wealth of information contained in the high-fidelity waveform data is discarded, data which has long been known to contain useful information on cardiovascular performance. Here we summarise a new mathematical method, attractor reconstruction, which enables the quantification of arterial waveform shape and variability in real-time...
October 30, 2018: Physiological Measurement
Ty Lees, Taryn Chalmers, David Burton, Eugene Zilberg, Thomas Penzel, Shail Lal, Sara Lal
OBJECTIVE: In this study, electroencephalography activity recorded during monotonous driving was investigated to examine the predictive capability of monopolar EEG analysis for fatigue/sleepiness in a cohort of train drivers. APPROACH: Sixty-three train drivers participated in the study, where 32- lead monopolar EEG data was recorded during a monotonous driving task. Participant sleepiness was assessed using the Pittsburgh sleep quality index (PSQI), the Epworth sleepiness scale (ESS), the Karolinksa sleepiness scale (KSS) and the checklist of individual strength 20 (CIS20)...
October 30, 2018: Physiological Measurement
Erik Reinertsen, Supreeth P Shashikumar, Amit J Shah, Shamim Nemati, Gari D Clifford
OBJECTIVE: Changes in heart rate (HR) and locomotor activity reflect changes in autonomic physiology, behavior, and mood. These systems may involve interrelated neural circuits that are altered in psychiatric illness, yet their interactions are poorly understood. We hypothesized interactions between HR and locomotor activity could be used to discriminate patients with schizophrenia from controls, and would be less able to discriminate non-psychiatric patients from controls. APPROACH: HR and locomotor activity were recorded via wearable patches in 16 patients with schizophrenia and 19 healthy controls...
October 30, 2018: Physiological Measurement
M Kropf, D Hayn, D Morris, Aravind-Kumar Radhakrishnan, E Belyavskiy, A Frydas, E Pieske-Kraigher, B Pieske, G Schreier
OBJECTIVE: Recent advantages in mHealth-enabled ECG recorders boosted the demand for algorithms, which are able to automatically detect cardiac anomalies with high accuracy. APPROACH: We present a combined method of classical signal analysis and machine learning which has been developed during the Computing in Cardiology Challenge (CinC) 2017. Almost 400 hand-crafted features have been developed to reflect the complex physiology of cardiac arrhythmias and their appearance in single-channel ECG recordings...
October 30, 2018: Physiological Measurement
Iman Alikhani, Kai Noponen, Arto Hautala, Tapio Seppänen
OBJECTIVE: Heart rate variability (HRV) is defined as the variation of the heart's beat to beat time intervals. Although HRV has been studied for decades, its response to stress tests and off-rest measurements is still under investigation. In this paper, we studied the influence of motion on HRV throughout different exercise tests, including a maximal running of healthy recreational runners, cycling, and walking tests of healthy subjects. APPROACH: In our proposed method, we utilized the motion trajectory (which is known to exist partially in HRV) measured by a three-channel accelerator (ACC)...
October 30, 2018: Physiological Measurement
Philip A Warrick, Masun Nabhan Homsi
OBJECTIVE: Atrial fibrillation is a common type of heart rhythm abnormality caused by a problem with the heart's electrical system. Early detection of this disease has important implications for stroke prevention and management. Our objective is to construct an intelligent tool that assists cardiologists in identifying automatically cardiac arrhythmias and noise in electrocardiogram (ECG) recordings. APPROACH: Our base deep classifier combined a convolutional neural network (CNNs) and a sequence of long short-term memory units, with pooling, dropout and normalization techniques to improve their accuracy...
October 30, 2018: Physiological Measurement
J S Minhas, R B Panerai, T G Robinson
OBJECTIVE: Cerebral blood flow (CBF) is influenced by changes in arterial CO2 (PaCO2 ). Recently, cerebral haemodynamic parameters were demonstrated to follow a four parameter logistic curve offering simultaneous assessment of dCA and CO2 vasoreactivity. However, the effects of sex on cerebral haemodynamics have yet to be described over a wide range of PaCO2 . APPROACH: CBF velocity (CBFV, transcranial Doppler), blood pressure (BP, Finometer) and end-tidal CO2 (EtCO2 , capnography) were measured in healthy volunteers at baseline, and in response to hypo- (-5 mmHg and  -10 mmHg below baseline) and hypercapnia (5% and 8% CO2 ), applied in random order...
October 24, 2018: Physiological Measurement
Philipp Sodmann, Marcus Vollmer, Neetika Nath, Lars Kaderali
OBJECTIVE: Electrocardiography is the most common tool to diagnose cardiovascular diseases. Annotation, segmentation and rhythm classification of ECGs are challenging tasks, especially in the presence of atrial fibrillation and other arrhythmias. Our aim is to increase the accuracy of heart rhythm estimation by the use of extreme gradient boosting trees and the development of a deep convolutional neural network for ECG segmentation. APPROACH: We trained a convolutional neural network with waveforms from PhysioNet databases to annotate QRS complexes, P waves, T waves, noise and interbeat ECG segments that characterize the essences of normal and irregular heart beats...
October 24, 2018: Physiological Measurement
Dirk Cysarz, Friedrich Edelhäuser, Michal Javorka, Nicola Montano, Alberto Porta
OBJECTIVE: Symbolic transformations of the cardiac interbeat interval series yield a coarse-grained description of the dynamical information of the underlying system and complement standard measures of heart rate variability. The most commonly utilized coarse graining procedures are strongly influenced by the presence of a few extreme values wasting precious symbols to code very unlikely values. APPROACH: Here, we used a transformation procedure that ensured the appearance of each symbol with equal probability using a short alphabet, A 4   =  {0, 1, 2, 3}, and a long alphabet, A 6   =  {0, 1, 2, 3, 4, 5}...
October 24, 2018: Physiological Measurement
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