Multiscale sample entropy

多尺度样本熵
  • 文章类型: English Abstract
    Motor imagery is often used in the fields of sports training and neurorehabilitation for its advantages of being highly targeted, easy to learn, and requiring no special equipment, and has become a major research paradigm in cognitive neuroscience. Transcranial direct current stimulation (tDCS), an emerging neuromodulation technique, modulates cortical excitability, which in turn affects functions such as locomotion. However, it is unclear whether tDCS has a positive effect on motor imagery task states. In this paper, 16 young healthy subjects were included, and the electroencephalogram (EEG) signals and near-infrared spectrum (NIRS) signals of the subjects were collected when they were performing motor imagery tasks before and after receiving tDCS, and the changes in multiscale sample entropy (MSE) and haemoglobin concentration were calculated and analyzed during the different tasks. The results found that MSE of task-related brain regions increased, oxygenated haemoglobin concentration increased, and total haemoglobin concentration rose after tDCS stimulation, indicating that tDCS increased the activation of task-related brain regions and had a positive effect on motor imagery. This study may provide some reference value for the clinical study of tDCS combined with motor imagery.
    运动想象(MI)以其针对性强、方便易学、无需特殊设备等优点,常被用于体育训练和神经康复等领域,并成为认知神经科学的一种主要研究范式。经颅直流电刺激(tDCS)作为一种新兴的神经调控技术,可调节皮质兴奋性,进而影响运动等功能,然而tDCS对于运动想象任务态是否具有积极影响目前尚不明确。本文纳入了16名年轻健康受试者,采集受试者在接受tDCS前、后执行运动想象任务时的脑电(EEG)信号和近红外光谱(NIRS)信号,计算并分析了不同任务期间的多尺度样本熵(MSE)和血红蛋白浓度变化情况。结果发现,tDCS刺激后任务相关脑区的MSE升高,含氧血红蛋白浓度增加,总血红蛋白浓度上升,表明tDCS提高了任务相关脑区的激活程度,说明tDCS对运动想象具有积极作用。本研究或可为tDCS联合运动想象的临床研究提供一定的参考价值。.
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  • 文章类型: Journal Article
    探索情绪在脑电图信号中的表现形式有助于提高情绪识别的准确性。本文介绍了基于Russell'scenterplex模型的基于EEG信号多尺度信息分析(MIA)的新特征,用于在四个维度上区分情绪状态。这些算法被应用于DEAP数据库上的特征提取,其中包括时域中的多尺度脑电复杂性指数,集成经验模态分解增强了频域中的能量和模糊熵。采用支持向量机和交叉验证方法对分类精度进行评估。MIA方法的分类性能(准确率=62.01%,精度=62.03%,召回率/敏感度=60.51%,特异性=82.80%)远高于经典方法(准确率=43.98%,精度=43.81%,召回率/敏感度=41.86%,和特异性=70.50%),基于离散小波变换提取的特征包含相似能量,分形维数,和样本熵。在这项研究中,我们发现,情绪识别与EEG信号的高频振荡(51-100Hz)而不是低频振荡(0.3-49Hz)更相关,额叶和颞叶区域的重要性高于其他区域。这样的信息具有预测能力并且可以提供对分析EEG信号中的高频振荡的多尺度信息的更多见解。
    Exploring the manifestation of emotion in electroencephalogram (EEG) signals is helpful for improving the accuracy of emotion recognition. This paper introduced the novel features based on the multiscale information analysis (MIA) of EEG signals for distinguishing emotional states in four dimensions based on Russell\'s circumplex model. The algorithms were applied to extract features on the DEAP database, which included multiscale EEG complexity index in the time domain, and ensemble empirical mode decomposition enhanced energy and fuzzy entropy in the frequency domain. The support vector machine and cross validation method were applied to assess classification accuracy. The classification performance of MIA methods (accuracy = 62.01%, precision = 62.03%, recall/sensitivity = 60.51%, and specificity = 82.80%) was much higher than classical methods (accuracy = 43.98%, precision = 43.81%, recall/sensitivity = 41.86%, and specificity = 70.50%), which extracted features contain similar energy based on a discrete wavelet transform, fractal dimension, and sample entropy. In this study, we found that emotion recognition is more associated with high frequency oscillations (51-100Hz) of EEG signals rather than low frequency oscillations (0.3-49Hz), and the significance of the frontal and temporal regions are higher than other regions. Such information has predictive power and may provide more insights into analyzing the multiscale information of high frequency oscillations in EEG signals.
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  • 文章类型: Journal Article
    目前,连续血糖监测(CGM)设备的快速发展为糖尿病患者(包括妊娠期糖尿病患者)的治疗带来了新的见解.复杂性和分形最近正在快速发展,用于提取使用CGM测量的葡萄糖动力学中包含的信息。尽管科学家已经研究了糖尿病和非糖尿病之间葡萄糖动力学复杂性的差异,以发现更好的糖尿病护理方法,没有人分析在采用CGM成功治疗2型糖尿病孕妇的过程中葡萄糖动力学的复杂性和分形性.因此,我们使用功率谱密度(PSD)分析了复杂性和分形性,临床病例中的多尺度样本熵(MSE)和多重分形去趋势波动分析(MF-DFA)。我们的结果表明(i)血糖动力学中存在多重分形行为;(ii)α稳定分布比高斯分布更好地拟合葡萄糖增量数据;(iii)多尺度熵表示的“全局”复杂性,成功治疗后,光谱指数和Hurst指数增加,多重分形谱显示的“局部”复杂性降低。我们的结果提供的发现可能为医疗保健提供者管理2型糖尿病孕妇的血糖水平带来价值,并为科学家在治疗糖尿病的临床实践中应用复杂性和分形性提供参考。
    Currently, the rapid development of continuous glucose monitoring (CGM) device brings new insights into the treatment of diabetic patients including those during pregnancy. Complexity and fractality have recently under fast development for extracting information embodied in glucose dynamics measured using CGM. Although scientists have investigated the difference of complexity in glucose dynamics between diabetes and non-diabetes in order to discover better approaches for diabetes care, no one has analyzed the complexity and fractality of glucose dynamics during the process of adopting CGM to successfully treat pregnant women with type 2 diabetes. Thus, we analyzed the complexity and fractality using power spectral density (PSD), multi-scale sample entropy (MSE) and multifractal detrended fluctuation analysis (MF-DFA) in a clinical case. Our results show that (i) there exists multifractal behavior in blood glucose dynamics; (ii) the alpha stable distribution fits to the glucose increment data better than the Gaussian distribution; and (iii) the \"global\" complexity indicated by multiscale entropy, spectrum exponent and Hurst exponent increase and the \"local\" complexity indicated by multifractal spectrum decrease after the successful therapy. Our results offer findings that may bring value to health care providers for managing glucose levels of pregnant women with type 2 diabetes as well as provide scientists a reference on applying complexity and fractality in the clinical practice of treating diabetes.
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