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multiscale entropy

Anat Vilnai Lubetzky, Sarah Westcott McCoy, Robert Price, Deborah Kartin
CONTEXT:  Proprioceptive training on compliant surfaces is used to rehabilitate and prevent ankle sprains. The ability to improve proprioceptive function via such training has been questioned. Achilles tendon vibration is used in motor-control research as a form of proprioceptive stimulus. Using measures of postural steadiness with nonlinear measures to elucidate control mechanisms, tendon vibration can be applied to investigate the underlying rationale of proprioceptive training. OBJECTIVE:  To test whether the effect of vibration on young adults' postural control depended on the support surface...
January 26, 2017: Journal of Athletic Training
Kuang-Cheng Chan, Jia-Rong Yeh, Wei-Zen Sun
BACKGROUND & AIMS: Model for end-stage liver disease (MELD) score has been extensively used to prioritize patients for liver transplantation and determine their prognosis, but with limited predictive value. Autonomic dysfunction may correlate with increased mortality after liver transplant. In this study, two autonomic biomarkers, complexity and deceleration capacity, were added to the predicting model for one-year mortality after liver transplantation. METHODS: Thirty patients with end-stage liver diseases awaiting liver transplantation were included...
January 20, 2017: Liver International: Official Journal of the International Association for the Study of the Liver
Cristine Sortica da Costa, Michal M Placek, Marek Czosnyka, Brenno Cabella, Magdalena Kasprowicz, Topun Austin, Peter Smielewski
A characteristic feature of complex healthy biological systems is the ability to react and adapt to minute changes in the environment. This 'complexity' manifests itself in highly irregular patterns of various physiological measurements. Here, we apply Multiscale Entropy (MSE) analysis to assess the complexity of systemic and cerebral near-infrared spectroscopy (NIRS) signals in a cohort of 61 critically ill preterm infants born at median (range) gestational age of 26 (23-31) weeks, before 24 h of life. We further correlate the complexity of these parameters with brain injury and mortality...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
Ary L Goldberger, Teresa Henriques, Sara Mariani
An abrupt transition from sinus cardiac rhythm to atrial fibrillation (AF) is common in patients with chronic heart failure (CHF). We propose a conceptual framework for viewing this malignant transition in terms of a type of sublimation marked by the switch from highly periodic sinus interbeat interval dynamics characteristic of CHF to a state of random disorganization with AF. Sublimation of physical substances involves an increase in entropy via heat transfer. In contrast, the disease-related sublimation-like behavior involves a loss of information content, associated decreases in cardiac bioenergetic capacity and in multiscale entropy...
November 2016: Complexity
Luiz Eduardo Virgilio Silva, Carlos Alberto Aguiar Silva, Helio C Salgado, Rubens Fazan
Analysis of heart rate variability (HRV) by nonlinear approaches has been gaining interest due to their ability to extract additional information from heart rate (HR) dynamics, not detectable by traditional approaches. Nevertheless, the physiological interpretation of nonlinear approaches remains unclear. Therefore, we propose long-term (60 min) protocols involving selective blockade of cardiac autonomic receptors to investigate the contribution of sympathetic and parasympathetic function upon nonlinear dynamics of HRV...
December 23, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Quan Liu, Yi-Feng Chen, Shou-Zen Fan, Maysam F Abbod, Jiann-Shing Shieh
Electroencephalography (EEG) has been widely utilized to measure the depth of anaesthesia (DOA) during operation. However, the EEG signals are usually contaminated by artifacts which have a consequence on the measured DOA accuracy. In this study, an effective and useful filtering algorithm based on multivariate empirical mode decomposition and multiscale entropy (MSE) is proposed to measure DOA. Mean entropy of MSE is used as an index to find artifacts-free intrinsic mode functions. The effect of different levels of artifacts on the performances of the proposed filtering is analysed using simulated data...
December 19, 2016: Medical & Biological Engineering & Computing
Tian Liu, Yanni Chen, Desheng Chen, Chenxi Li, Yusheng Qiu, Jue Wang
Autism spectrum disorder (ASD) is a severe neurodevelopment disorder. This study tests the hypothesis that children with ASD show atypical intrinsic complexity of brain activity. Electroencephalogram data were collected from boys with ASD and matching normal typically developing children while performing an observation and an imitation task. The multiscale entropy was estimated within the 0.5-30 Hz frequency band over 30 time scales using a coarse-grained procedure. A decreased electroencephalogram complexity was observed in the ASD children both during the observation and during the imitation tasks...
February 8, 2017: Neuroreport
Alan H Gee, Riccardo Barbieri, David Paydarfar, Premananda Indic
OBJECTIVE: Episodes of bradycardia are common and recur sporadically in preterm infants, posing a threat to the developing brain and other vital organs. We hypothesize that bradycardias are a result of transient temporal destabilization of the cardiac autonomic control system and that fluctuations in the heart rate signal might contain information that precedes bradycardia. We investigate infant heart rate fluctuations with a novel application of point process theory. METHODS: In 10 preterm infants, we estimate instantaneous linear measures of the heart rate signal in neonates, use these measures to extract statistical features of bradycardia, and propose a simplistic framework for prediction of bradycardia...
November 24, 2016: IEEE Transactions on Bio-medical Engineering
Wissam A Saidi, Joshua J Choi
Hybrid organic-inorganic perovskites, as well as the perovskites in general, are known for their phase complexity evidenced by the stabilization of different polymorphs, and thus an understanding of their regions of stability and transitions can be important for their photovoltaic and optoelectronic technologies. Here we use a multiscale approach based on first-principles calculations with van der Waals corrections and classical force-field molecular dynamics to determine the finite-temperature properties of the tetragonal and cubic phases of CH3NH3PbI3...
October 14, 2016: Journal of Chemical Physics
Cui Su, Zhenhu Liang, Xiaoli Li, Duan Li, Yongwang Li, Mauro Ursino
OBJECTIVE: Multiscale permutation entropy (MSPE) is becoming an interesting tool to explore neurophysiological mechanisms in recent years. In this study, six MSPE measures were proposed for on-line depth of anesthesia (DoA) monitoring to quantify the anesthetic effect on the real-time EEG recordings. The performance of these measures in describing the transient characters of simulated neural populations and clinical anesthesia EEG were evaluated and compared. METHODS: Six MSPE algorithms-derived from Shannon permutation entropy (SPE), Renyi permutation entropy (RPE) and Tsallis permutation entropy (TPE) combined with the decomposition procedures of coarse-graining (CG) method and moving average (MA) analysis-were studied...
2016: PloS One
Pierre Gaspard
Theoretical advances are reported on the kinetics and thermodynamics of free and template-directed living copolymerizations. Until recently, the kinetic theory of these processes had only been established in the fully irreversible regime, in which the attachment rates are only considered. However, the entropy production is infinite in this regime and the approach to thermodynamic equilibrium cannot be investigated. For this purpose, the detachment rates should also be included. Inspite of this complication, the kinetics can be exactly solved in the regimes of steady growth and depolymerization...
November 13, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Julie Courtiol, Dionysios Perdikis, Spase Petkoski, Viktor Müller, Raoul Huys, Rita Sleimen-Malkoun, Viktor K Jirsa
BACKGROUND: Multiscale Entropy (MSE) estimates the predictability of a signal over multiple temporal scales. It has been recently applied to study brain signal variability, notably during aging. The grounds of its application and interpretation remain unclear and subject to debate. METHOD: We used both simulated and experimental data to provide an intuitive explanation of MSE and to explore how it relates to the frequency content of the signal, depending on the amount of (non)linearity and stochasticity in the underlying dynamics...
September 14, 2016: Journal of Neuroscience Methods
Hyun Gu Kang, Jonathan B Dingwell
Age-related gait changes may be due to the loss of complexity in the neuromuscular system. This theory is disputed due to inconsistent results from single-scale analyses. Also, behavioral adaptations may confound these changes. We examined whether EMG dynamics during gait is less complex in older adults over a range of timescales using the multiscale entropy method, and whether slower walking attenuates this effect. Surface EMG was measured from the left vastus lateralis (VL), biceps femoris (BF), gastrocnemius (GA), and tibialis anterior (TA) in 17 young and 18 older adults as they walked on a treadmill for 5 minutes at 0...
2016: PloS One
Tanmoy Sanyal, M Scott Shell
Bottom-up multiscale techniques are frequently used to develop coarse-grained (CG) models for simulations at extended length and time scales but are often limited by a compromise between computational efficiency and accuracy. The conventional approach to CG nonbonded interactions uses pair potentials which, while computationally efficient, can neglect the inherently multibody contributions of the local environment of a site to its energy, due to degrees of freedom that were coarse-grained out. This effect often causes the CG potential to depend strongly on the overall system density, composition, or other properties, which limits its transferability to states other than the one at which it was parameterized...
July 21, 2016: Journal of Chemical Physics
William T Schnettler, Ary L Goldberger, Steven J Ralston, Madalena Costa
BACKGROUND: Visual non-stress test interpretation lacks the optimal specificity and observer-agreement of an ideal screening tool for intrauterine fetal demise (IUFD) syndrome prevention. Computational methods based on traditional heart rate variability have also been of limited value. Complexity analysis probes properties of the dynamics of physiologic signals that are otherwise not accessible and, therefore, might be useful in this context. OBJECTIVE: To explore the association between fetal heart rate (FHR) complexity analysis and subsequent IUFD...
August 2016: European Journal of Obstetrics, Gynecology, and Reproductive Biology
Lawrence R Frank, Vitaly L Galinsky
The ability of functional magnetic resonance imaging (FMRI) to noninvasively measure fluctuations in brain activity in the absence of an applied stimulus offers the possibility of discerning functional networks in the resting state of the brain. However, the reconstruction of brain networks from these signal fluctuations poses a significant challenge because they are generally nonlinear and nongaussian and can overlap in both their spatial and temporal extent. Moreover, because there is no explicit input stimulus, there is no signal model with which to compare the brain responses...
September 2016: Neural Computation
A Khalil, A Humeau-Heurtier, L Gascoin, P Abraham, G Mahé
PURPOSE: It has long been known that age plays a crucial role in the deterioration of microvessels. The assessment of such deteriorations can be achieved by monitoring microvascular blood flow. Laser speckle contrast imaging (LSCI) is a powerful optical imaging tool that provides two-dimensional information on microvascular blood flow. The technique has recently been commercialized, and hence, few works discuss the postacquisition processing of laser speckle contrast images recorded in vivo...
July 2016: Medical Physics
Yen-Hung Lin, Chen Lin, Yi-Heng Ho, Vin-Cent Wu, Men-Tzung Lo, Kuan-Yu Hung, Li-Yu Daisy Liu, Lian-Yu Lin, Jenq-Wen Huang, Chung-Kang Peng
Cardiovascular disease is one of the leading causes of death in patients with advanced renal disease. The objective of this study was to investigate impairments in heart rhythm complexity in patients with end-stage renal disease. We prospectively analyzed 65 patients undergoing peritoneal dialysis (PD) without prior cardiovascular disease and 72 individuals with normal renal function as the control group. Heart rhythm analysis including complexity analysis by including detrended fractal analysis (DFA) and multiscale entropy (MSE) were performed...
2016: Scientific Reports
Wen-Yao Pan, Mao-Chang Su, Hsien-Tsai Wu, Te-Jen Su, Meng-Chih Lin, Cheuk-Kwan Sun
OBJECTIVE: Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular disease because of its associated autonomic nervous and vascular regulatory dysfunctions. We tested the hypothesis that the multiscale entropy (MSE) approach to heart rate variability analysis may be used for evaluating OSA severity through simultaneous assessment of these abnormalities. METHODS: A total of 147 subjects were divided into four groups according to apnea-hypopnea index (AHI) from polysomnography (PSG): Snoring without OSA (5 > AHI, n = 31), mild (5 ≤ AHI < 15, n = 31), moderate (15 ≤ AHI < 30, n = 41), and severe (AHI ≥ 30, n = 44) OSA...
April 2016: Sleep Medicine
M C Bisi, R Stagni
Multiscale entropy (MSE) has been applied in biomechanics to evaluate gait stability during human gait and was found to be a promising method for evaluating fall risk in elderly and/or pathologic subjects. The hypothesis of this work is that gait complexity is a relevant parameter of gait development during life, decreasing from immature to mature gait and then increasing again during old age. In order to verify this hypothesis, MSE was applied on trunk acceleration data collected during gait of subjects of different ages: toddlers at the onset of walking, pre-scholar and scholar children, adolescents, young adults, adults and elderlies...
June 2016: Gait & Posture
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