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Physiological Measurement

Peter A Muller, Jennifer L Mueller, Michelle Mellenthin, Rashmi Murthy, Michael Capps, Brandie Wagner, Melody Alsaker, Robin Deterding, Scott D Sagel, Jordana Hoppe
Lung function monitoring by spiromety plays a critical role in the clinical care of pediatric cystic fibrosis (CF) patients, but many young children are unable to perform spirometry, and the outputs are often normal even in the presence of lung disease. Measures derived from electrical impedance tomography (EIT) images were studied for their utility as potential surrogates for spirometry in CF patients and to assess response to intravenous antibiotic treatment for acute pulmonary exacerbations (PEx) in a subset of patients...
March 22, 2018: Physiological Measurement
Francesc Font-Clos, Stefano Zapperi, Caterina A M La Porta
OBJECTIVE: Observational studies suggest that obesity might have a Mendelian origin, but it is not clear if gene expression patterns observed in obese subjects are secondary to genetic traits or not. 
 Approach: Here we test a transcriptomic signature of obesity previously identified by our group
 on a large cohort of twin subjects (TwinsUK). 
 Main results: The results show that the signature correlates strongly both with the body mass index (BMI) and fat mass...
March 21, 2018: Physiological Measurement
Marija D Ivanovic, Jovana Petrovic, Andrej Savic, Goran Gligoric, Marjan Miletic, Miodrag Vukcevic, Bosko Bojovic, Ljupco Hadzievski, Tom D P Allsop, David J Webb
The ventilators involved in non-invasive mechanical ventilation commonly provide ventilator support via a facemask. The interface of the mask with a patient promotes air leaks that cause errors in the feedback information provided by a pneumatic sensor and hence patient-ventilator asynchrony with multiple negative consequences. Our objective is to test the possibility of using chest-wall motion measured by an optical fibre-grating sensor as a more accurate non-invasive ventilator triggering mechanism.
 Approach: The basic premise of our approach is that the measurement accuracy can be improved by using a triggering signal that precedes pneumatic triggering in the neuro-ventilatory coupling sequence...
March 19, 2018: Physiological Measurement
James Hope, Frederique Vanholsbeeck, A J McDaid
In neural interfaces for peripheral nerve a trade-off exists between the level of invasiveness and the selectivity of neural recordings. In this study, we implement electrical impedance tomography (EIT) in a nerve cuff with the aim to investigate the achievable level of selectivity.
 Approach: Established modelling approaches in neural-EIT are expanded on to be used, for the first time, on myelinated fibres which are abundant in mammalian peripheral nerves and transmit motor commands. The model is then used to evaluate the viability of using EIT with a nerve cuff to record neural activity in peripheral nerves...
March 16, 2018: Physiological Measurement
G H Renier Botha, Grant Theron, Rob Warren, Marisa Klopper, Kheertan Dheda, Paul van Helden, Thomas R Niesler
Globally, tuberculosis (TB) remains one of the most deadly diseases. Although several effective diagnosis methods exist, in lower income countries clinics may not be in a position to afford expensive equipment and employ the trained experts needed to interpret results. In these situations, symptoms including cough are commonly used to identify patients for testing. However, self-reported cough has suboptimal sensitivity and specificity, which may be improved by digital detection. This study investigates a simple and easily applied method for TB screening based on the automatic analysis of coughing sounds...
March 15, 2018: Physiological Measurement
Barry James McDermott, Emily Porter, Marggie Jones, Brian McGinley, Martin O'Halloran
OBJECTIVE: The theoretical basis, experimental implementation, and proof of concept of a novel Electrical Impedance Tomography (EIT) imaging technique, called Symmetry Difference EIT, is described. This technique is applicable in situations where there is inherent symmetry in the region being imaged. METHODS: The sample scenario of the human head is used to describe the technique. The head is largely symmetrical across the sagittal plane. A unilateral lesion such as a haemorrhage or region of ischaemia distorts that symmetry...
March 13, 2018: Physiological Measurement
Yogev Koren, Yoav Raanan, Yisrael Parmet, Simona Bar-Haim
BACKGROUND AND OBJECTIVE: Walking is a complex human behavior, usually performed in a dynamic environment. Gait parameters are thought to reflect this complexity. Re-StepTM is a therapy system in the form of a computerized shoe, originally developed for the training and rehabilitation of individuals with brain damage. This system may be used as model for studying the complexity that underlies gait. As the first step, we present here the feasibility of the model, after establishing the validity and reliability of stride time and stride-time variability, observed in healthy adults...
March 13, 2018: Physiological Measurement
Nick Polydorides
We propose a numerical framework to simulate the Lorentz Force Electrical Impedance Tomography (LFEIT) measurements on accurate electrode models and an image reconstruction scheme for which data on two pairs of electrodes are sufficient. The adopted finite element-based complete electrode model encompasses the electrode's geometry and contact impedance, accounting for the power losses at the contact interface. The results of our simulation study suggest that electrode modelling has a significant impact on the measurements and electrode model inaccuracies may be detrimental to the image reconstruction...
March 13, 2018: Physiological Measurement
John Prince, Siddharth Arora, Maarten De Vos
To better understand the longitudinal characteristics of Parkinson's disease (PD) through the analysis of finger tapping and memory tests collected remotely using smartphones. 
 Approach: Using a large cohort (312 PD subjects and 236 controls) of participants in the mPower study, we extract clinically validated features from a finger tapping and memory test to monitor the longitudinal behaviour of study participants. We investigate any discrepancy in learning rates associated with motor and non-motor tasks between PD subjects and healthy controls...
March 8, 2018: Physiological Measurement
Louiza Sophocleous, Inez Frerichs, Martijn Miedema, Merja Kallio, Thalia Papadouri, Christina Karaoli, Tobias Becher, David G Tingay, Anton van Kaam, Richard H Bayford, Andreas Daniel Waldmann
OBJECTIVE: Critically ill neonates and infants might particularly benefit from continuous chest electrical impedance tomography (EIT) monitoring at the bedside. In this study a textile 32-electrode interface for neonatal EIT examination has been developed and tested to validate its clinical performance. The objectives were to assess ease of use in a clinical setting, stability of contact impedance at the electrode-skin interface and possible adverse effects. APPROACH: Thirty preterm infants (gestational age: 30...
March 8, 2018: Physiological Measurement
Zhenhu Liang, Cheng Huang, Yongwang Li, Darren F Hight, Logan J Voss, Jamie W Sleigh, Xiaoli Li, Yang Bai

 Objective. Significant spectral characteristics of electroencephalogram (EEG) patterns exist in individual patients during re-establishing consciousness after general anesthesia. However, these EEG patterns cannot be quantitatively identified using commercially available depth of anesthesia (DoA) monitors. This study proposed an effective classification method and indices to classify these patterns among patients.
 Approach. Four types of emergence EEG patterns were identified based on EEG data set from 52patients undergoing sevoflurane general anesthesia from two hospitals...
March 7, 2018: Physiological Measurement
David A Nelson, Silas J Leavesley, Carmen D Zirlott, Xi-Ming Yang, James M Downey
Implementation of clinical guidelines for diagnosing Peripheral Artery Disease (PAD) will demand screening many millions of patients who are considered at-risk. This will demand faster, easier screening technologies to identify patients with compromised blood flow to the extremities. The feasibility of using surface temperature response to Ka band (26.5 - 40 GHz) near-field irradiation to assess skin blood flow was explored using an animal model. Ears of domestic rabbits were subjected to low power continuous wave radio frequency heating from an open-ended waveguide (WR-28) at f=35 GHz...
March 7, 2018: Physiological Measurement
Michelle Marie Harbin, Hanan Zavala, Justin R Ryder, Julia Steinberger, Alan R Sinaiko, David R Jacobs, Donald R Dengel
To examine the association of age, sex, and obesity status on endothelial-independent dilation (EID) among children and adolescents.
 Study Design: This study examined 264 children (143 males) between 8 to 18 years old (mean±SD: age=14.3±2.7 years). Endothelial-independent dilation was assessed via ultrasound imaging of the brachial artery following administration of 0.3 milligrams of sublingual nitroglycerin. A one-way analysis of variance with Bonferroni post-hoc comparisons assessed sex-differences in percent peak EID dilation (EID%-peak) and EID area under the curve (EID%-AUC), while analysis of covariance (ANCOVA) adjusted for race, age, body mass index percentile (BMI-percentile), and brachial artery diameter...
March 7, 2018: Physiological Measurement
Qing Ji, Fei Wang, Rui Zhou, Jianhua Li, Jian Wang, Xuesong Ye
Impaired ankle dorsal and plantar flexor function is a frequent sequela of stroke. A better assessment of ankle muscle activation would be highly significant for stroke rehabilitation. The challenge in implementing current electromyography (EMG)-based assessments is due to problems with the variability and individuality of ankle muscle EMG profiles during walking. We have been studying a new technique using the muscle synergy method to quantify the characteristics that underlie ankle muscle activation to address this issue...
February 28, 2018: Physiological Measurement
Francisco Londono-Hoyos, Payman Zamani, Melissa Beraun, Izzah Vassim, Patrick Segers, Julio A Chirinos
OBJECTIVE: Increased penetration of pulsatile power to the brain has been implicated in the pathogenesis of age-related cognitive dysfunction and dementia, a common comorbidity in patients with heart failure and preserved ejection fraction (HFpEF). However, there is a lack of knowledge on the effects of organic and inorganic nitrates administration in this population on the power carried by pressure and flow waves traveling through the proximal aorta and penetrating the carotid artery into the brain microvasculature...
February 28, 2018: Physiological Measurement
Wei Zhong, Lijuan Liao, Xuemei Guo, Guoli Wang
OBJECTIVE: Non-Invasive foetal electrocardiography (NI-FECG) has the
 potential to provide more additional clinical information for detecting and diagnosing
 fetal diseases. We propose and demonstrate a deep learning approach for fetal QRS
 complex detection from raw NI-FECG signals by using Convolutional Neural Network
 (CNN) model. The main objective is to investigate whether reliable fetal QRS complex
 detection performance can still be obtained from features of single-channel NI-FECG
 signals, without canceling maternal ECG (MECG) signals...
February 27, 2018: Physiological Measurement
John Allen, Costanzo Di Maria, Samuel George Urwin, Alan Murray, Lesley Ottewell, Bridget Griffiths
Patients with systemic sclerosis (SSc) experience significant morbidity and mortality, therefore, the development of tests to aid its early diagnosis are very important. The aim of this pilot study was to assess the diagnostic value of novel optical non-invasive skin fluorescence spectroscopy (FS) and tissue oxygen saturation (TOS) viability measurements in patients with established SSc. Two groups were studied, comprising 14 SSc patients and 9 healthy controls (93% and 73% females, respectively). FS and TOS measurements were collected from 3 body sites: the forearm, chest, and calf...
February 22, 2018: Physiological Measurement
Qianli D Y Ma, Changjuan Ji, Huanhuan Xie, Kai Yin, Zhen Ma, Chunhua Bian
The aim of this study is to investigate the coupling behavior between heartbeat and pulse of blood flow at different sleep stages, and to explore the feasibility of using this coupling strength for automatic sleep staging.
 Approach: The electrocardiogram (ECG) and photoplethysmography (PPG) signals are recorded during sleep, and R-wave-to-R-wave intervals (RRI) and Pulse-to-Pulse intervals (PPI) are extracted respectively. The detrended cross-correlation analysis (DCCA) is applied to quantify long-range cross correlations between the RRIs and PPIs across sleep stages...
February 16, 2018: Physiological Measurement
Mayo Faulkner, Sana Hannan, Kirill Y Aristovich, James Avery, David S Holder
<i>Objective</i>. Electrical Impedance Tomography (EIT) can image impedance changes associated with evoked physiological activity in the cerebral cortex using an array of epicortical electrodes. An impedance change is observed as the externally applied current, normally confined to the extracellular space is admitted into the conducting intracellular space during neuronal depolarisation. The response is largest at DC and decreases at higher frequencies due to capacitative transfer of current across the membrane...
February 16, 2018: Physiological Measurement
Sokratis Makrogiannis, Fatima Boukari, Luigi Ferrucci
In this paper we introduce a methodology for hard and soft tissue quantification at proximal, intermediate and distal tibia sites using peripheral Quantitative Computed Tomography (pQCT) scans. Quantification of bone properties is crucial for estimating bone structure resistance to mechanical stress and adaptations to loading. Soft tissue variables can be computed to investigate muscle volume and density, muscle-bone relationship, and fat infiltration.
 Approach: We employed implicit active contour models and clustering techniques for automated segmentation and identification of bone, muscle and fat at 4%, 38%, and 66% tibia length...
February 15, 2018: Physiological Measurement
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