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multiscale entropy

Alexey Brazhe
New spatial entropy and complexity measures for two-dimensional patterns are proposed. The approach is based on the notion of disequilibrium and is built on statistics of directional multiscale coefficients of the fast finite shearlet transform. Shannon entropy and Jensen-Shannon divergence measures are employed. Both local and global spatial complexity and entropy estimates can be obtained, thus allowing for spatial mapping of complexity in inhomogeneous patterns. The algorithm is validated in numerical experiments with a gradually decaying periodic pattern and Ising surfaces near critical state...
June 2018: Physical Review. E
Suliang Chen, Mathew J Gallagher, Marios C Papadopoulos, Samira Saadoun
The injured spinal cord is a complex system influenced by many local and systemic factors that interact over many timescales. To help guide clinical management, we developed a technique that monitors intraspinal pressure from the injury site in patients with acute, severe traumatic spinal cord injuries. Here, we hypothesize that spinal cord injury alters the complex dynamics of the intraspinal pressure signal quantified by computing hourly the detrended fluctuation exponent alpha, multiscale entropy, and maximal Lyapunov exponent lambda...
2018: Frontiers in Neurology
Zhenxi Song, Bin Deng, Jiang Wang, Ruofan Wang
OBJECTIVE: This paper aims to explore affordable biomarkers of Alzheimer's disease (AD) based on noninvasive, low-cost and portability electroencephalography (EEG) signals. METHODS: By combining multiscale analysis and embedding space theory, a novel strategy was developed for constructing brain functional network inferred from generalized composite multiscale entropy vector (GCMSEV). Functional network analysis and seed analysis were used for comparing AD pattern vs...
May 9, 2018: IEEE Transactions on Bio-medical Engineering
H Piitulainen, T Rantalainen, J P Kulmala, H Mäenpää
Children with cerebral palsy (CP) have gait impairments, and their gait is affected by concurrent tasks. We used inertial measurement units (IMU) to quantify CP-related gait complexity alterations, and identify effects of dual tasks on gait variability from 12 children with CP and 23 typically developed (TD) controls. The data were collected for normal and dual-tasks (motor; carrying a tray, cognitive; word naming) during walking. Step duration and adjusted multiscale entropy (MSE) index were computed. In overall, children with CP had shorter step duration and greater gait complexity than TD...
July 3, 2018: Gait & Posture
Anne Humeau-Heurtier, Ana Carolina Mieko Omoto, Luiz E V Silva
The multiscale entropy (MSE1D ) measure is now widely used to quantify the complexity of time series. The development of complexity measures for images is also a long-standing goal. Recently, the bi-dimensional version of MSE1D has been proposed (MSE2D ) to analyze images. The interpretation of MSE2D curves and the applications to real data are still emergent. Because the coarse-graining step in the MSE2D computation changes the frequency content of the image, we hypothesized a possible dependence between MSE2D and the discrete Fourier transform (DFT)...
June 25, 2018: Computers in Biology and Medicine
Albert C Yang, Shih-Jen Tsai, Ching-Po Lin, Chung-Kang Peng
Complexity analysis of resting-state blood oxygen level-dependent (BOLD) signals using entropy methods has attracted considerable attention. However, investigation on the bias of entropy estimates in resting-state functional magnetic resonance imaging (fMRI) signals and a general strategy for selecting entropy parameters is lacking. In this paper, we present a minimizing error approach to reduce the bias of sample entropy (SampEn) and multiscale entropy (MSE) in resting-state fMRI data. The strategy explored a range of parameters that minimized the relative error of SampEn of BOLD signals in cerebrospinal fluids where minimal physiologic information was present, and applied these parameters to calculate SampEn of BOLD signals in gray matter regions...
2018: Frontiers in Neuroscience
Hongye Wang, Penny M Pexman, Gary Turner, Filomeno Cortese, Andrea B Protzner
Recent empirical work suggests that the dynamics of brain function, as measured by brain signal variability, differs between younger and older adults. We extended this work by examining how the relationship between brain signal variability and age is altered in the context of expertise. We recorded electroencephalography from Scrabble experts and controls during a visual word recognition task. To measure variability, we used multiscale entropy, which emphasizes the way brain signals behave over a range of timescales and can differentiate the variability of a complex system (the brain) from a purely random system...
May 18, 2018: Neurobiology of Aging
David Rodbard
Glycemic variability (GV) is a major consideration when evaluating quality of glycemic control. GV increases progressively from prediabetes through advanced T2D and is still higher in T1D. GV is correlated with risk of hypoglycemia. The most popular metrics for GV are the %Coefficient of Variation (%CV) and standard deviation (SD). The %CV is correlated with risk of hypoglycemia. Graphical display of glucose by date, time of day, and day of the week, and display of simplified glucose distributions showing % of time in several ranges, provide clinically useful indicators of GV...
June 2018: Diabetes Technology & Therapeutics
Yong Lv, Rui Yuan, Tao Wang, Hewenxuan Li, Gangbing Song
Rolling bearings play a crucial role in rotary machinery systems, and their operating state affects the entire mechanical system. In most cases, the fault of a rolling bearing can only be identified when it has developed to a certain degree. At that moment, there is already not much time for maintenance, and could cause serious damage to the entire mechanical system. This paper proposes a novel approach to health degradation monitoring and early fault diagnosis of rolling bearings based on a complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and improved multivariate multiscale sample entropy (MMSE)...
June 14, 2018: Materials
Guangjun Wang, Shuyong Jia, Hongyan Li, Ze Wang, Weibo Zhang
To investigate the relationship between local blood flux and heart rate variability following different thermal stimulations, healthy subjects were recruited and subject to different thermal stimulations on the right forearm. Multiscale entropy and multiscale fuzzy entropy were used to measure the complexity of the local blood flux, and the approximate entropy was calculated to evaluate the HRV complexity. The results indicated that thermal stimulation significantly increased local blood flux and that different temperature stimulations resulted in different complexities in local blood flux...
June 12, 2018: Scientific Reports
J P Chiverton, A Kao, M Roldo, G Tozzi
Fibrous nanomaterials such as electrospun materials have many uses ranging from tissue engineering to biosensors. High-resolution imaging is an important component in the characterization of these materials. Important parameters required to predict and study the properties of fibre rich materials include diameter and orientation distribution as well as fibre spacing. The orientations and the relative dimensions of the fibres can be measured via specially designed imaging software. Difficulties in this measurement process can arise if fibres are distributed in close proximity to each other in relation to the resolution of the imaging modality...
June 6, 2018: Journal of Microscopy
Zhu Liu, Huizi Ma, Victoria Poole, Xuemei Wang, Zhan Wang, Yaqin Yang, Lanxi Meng, Brad Manor, Junhong Zhou, Tao Feng
Background: Impaired motor control is one of the most common symptoms of multiple system atrophy (MSA). It arises from dysfunction of the cerebellum and its connected neural networks, including the primary motor cortex (M1), and is associated with altered spontaneous (i.e., resting-state) brain network activity. Non-invasive repetitive transcranial magnetic stimulation (rTMS) selectively facilitates the excitability of supraspinal networks. Repeated rTMS sessions have been shown to induce long-term changes to both resting-state brain dynamics and behavior in several neurodegenerative diseases...
2018: Frontiers in Behavioral Neuroscience
Luis Santamaría, Ildefonso Ingelmo, Bryan Sinues, Laura Martínez, Fernando Teba
There are few studies comparing global versus local changes in spatial patterns in prostate cancer. In this study, stereological tools have been applied to find out if the cytokeratin18 (ck18) immunoexpression shows local changes in cancer compared to normal prostate. To verify if these changes are relevant to ascertain differences between normal (CTR) and cancer (Ca) cases, several parameters were estimated. Volume fraction of epithelium immunostained for ck18 (VV ck18), dispersion index of VV ck18, positional variance of VV ck18, and multiscale entropy analysis (MSE) to measure the tissue heterogeneity...
June 4, 2018: Histology and Histopathology
Gerard Moras, Bruno Fernández-Valdés, Jairo Vázquez-Guerrero, Julio Tous-Fajardo, Juliana Exel, Jaime Sampaio
OBJECTIVES: This study described the variability in acceleration during a resistance training task, performed in horizontal inertial flywheels without (NOBALL) or with the constraint of catching and throwing a rugby ball (BALL). DESIGN AND METHODS: Twelve elite rugby players (mean±SD: age 25.6±3.0years, height 1.82±0.07m, weight 94.0±9.9kg) performed a resistance training task in both conditions (NOBALL AND BALL). Players had five minutes of a standardized warm-up, followed by two series of six repetitions of both conditions: at the first three repetitions the intensity was progressively increased while the last three were performed at maximal voluntary effort...
May 24, 2018: Journal of Science and Medicine in Sport
Ram Sewak Singh, Barjinder Singh Saini, Ramesh Kumar Sunkaria
Objective: Cardiovascular diseases generate the highest mortality in the globe population, mainly due to coronary artery disease (CAD) like arrhythmia, myocardial infarction and heart failure. Therefore, an early identification of CAD and diagnosis is essential. For this, we have proposed a new approach to detect the CAD patients using heart rate variability (HRV) signals. This approach is based on subspaces decomposition of HRV signals using multiscale wavelet packet (MSWP) transform and entropy features extracted from decomposed HRV signals...
2018: Clujul Medical (1957)
Imtiaz Awan, Wajid Aziz, Imran Hussain Shah, Nazneen Habib, Jalal S Alowibdi, Sharjil Saeed, Malik Sajjad Ahmed Nadeem, Syed Ahsin Ali Shah
Considerable interest has been devoted for developing a deeper understanding of the dynamics of healthy biological systems and how these dynamics are affected due to aging and disease. Entropy based complexity measures have widely been used for quantifying the dynamics of physical and biological systems. These techniques have provided valuable information leading to a fuller understanding of the dynamics of these systems and underlying stimuli that are responsible for anomalous behavior. The single scale based traditional entropy measures yielded contradictory results about the dynamics of real world time series data of healthy and pathological subjects...
2018: PloS One
Xiaoling Chen, Ping Xie, Yuanyuan Zhang, Yuling Chen, Fangmei Yang, Litai Zhang, Xiaoli Li
Recently, functional corticomuscular coupling (FCMC) between the cortex and the contralateral muscle has been used to evaluate motor function after stroke. As we know, the motor-control system is a closed-loop system that is regulated by complex self-regulating and interactive mechanisms which operate in multiple spatial and temporal scales. Multiscale analysis can represent the inherent complexity. However, previous studies in FCMC for stroke patients mainly focused on the coupling strength in single-time scale, without considering the changes of the inherently directional and multiscale properties in sensorimotor systems...
2018: Frontiers in Neurology
Priyalakshmi Sheela, Subha D Puthankattil
Autism Spectrum Disorders (ASD) comprise all pervasive neurodevelopmental diseases marked by deficits in social and communication skills, delayed cognitive development, restricted and repetitive behaviors. The core symptoms begin in early childhood, may continue life-long resulting in poor performance in adult stage. Event-related potential (ERP) is basically a time-locked electroencephalogram signal elicited by various stimuli, related to sensory and cognitive processes. The various ERP based techniques used for the study of ASD are considered in this review...
May 19, 2018: International Journal of Developmental Neuroscience
Hongyun Liu, Zhao Yang, Fangang Meng, Lei Huang, Wei Qu, Hongwei Hao, Jianguo Zhang, Luming Li
OBJECTIVE: Vagus nerve stimulation (VNS) is an adjunctive treatment in drug-resistant epilepsy. The alterations in heart rate dynamics through VNS are not well understood. This study aimed to determine changes in heart rhythm complexity in association with VNS and to relate the findings to the outcome of VNS treatment in patients with drug-resistant epilepsy. METHODS: We prospectively analyzed 32 patients with drug-resistant epilepsy, who underwent VNS implantation, and 32 age- and sex-matched healthy control subjects...
June 2018: Epilepsy & Behavior: E&B
Kiyoumars Roushangar, Farhad Alizadeh, Jan Adamowski
Understanding precipitation on a regional basis is an important component of water resources planning and management. The present study outlines a methodology based on continuous wavelet transform (CWT) and multiscale entropy (CWME), combined with self-organizing map (SOM) and k-means clustering techniques, to measure and analyze the complexity of precipitation. Historical monthly precipitation data from 1960 to 2010 at 31 rain gauges across Iran were preprocessed by CWT. The multi-resolution CWT approach segregated the major features of the original precipitation series by unfolding the structure of the time series which was often ambiguous...
August 2018: Environmental Research
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