Estabilidad de la actividad eléctrica no lineal durante condiciones basales con los ojos cerrados / Nonlinear electrical activity stability in basal, eyes closed conditions

Introducción: El electroencefalograma permite registrar la actividad eléctrica cerebral en estado de reposo y durante la ejecución de tareas cognitivas. Objetivo: Evaluar si la actividad cerebral, analizada como dinámica no lineal, se mantiene estable durante diferentes ventanas temporales en una condición basal con ojos cerrados. Métodos: Se realizaron registros con electroencefalograma durante dos minutos a 14 estudiantes universitarios varones. Posteriormente, se compararon las medias de índices de Hurst (H) en ventanas temporales de 60, 30 y 10 segundos. Resultados: Las medias de los índices H son estables a través de diferentes ventanas temporales en las regiones prefrontales, temporales y occipitales. Conclusiones: Los registros de electroencefalograma en condiciones basales con los ojos cerrados son válidos para comparar protocolos experimentales de resolución de problemas cognitivos utilizando el exponente de Hurst en los sujetos de la muestra y en otros con características similares(AU)

Introduction: Electroencephalography makes it possible to record brain electrical activity at rest and during the performance of cognitive tasks. Objective: Determine whether brain activity analyzed as nonlinear dynamics remains stable during various time windows in basal, eyes closed conditions. Methods: Electroencephalographic records of 14 male university students were taken during two minutes. Hurst's index means (H) were then compared in time windows of 60, 30 and 10 seconds. Results: H index means are stable throughout the various time windows in the prefrontal, temporal and occipital regions. Conclusions: Electroencephalographic records in basal, eyes closed conditions are valid to compare experimental protocols for cognitive problem solving using the Hurst exponent in subjects from the sample as well as others of similar characteristics(AU)

Exploration about Characteristics of Blood Glucose Changes of Type 2 Diabetes Based on Dynamic Blood Glucose Hurst Index and Qi and Blood Flow Rule / 世界科学技术-中医药现代化

This paper aimed at discussing the characteristics of blood glucose changes of type 2 diabetes according to the flow rule of Qi and Blood as well as the Hurst index of dynamic blood glucose collected by CGMS. A total of 156 T2DM patients were selected from the Longhua Hospital Affiliated to Shanghai University of Traditional Chinese Medicine. After continuous monitoring of dynamic blood glucose for 3 consecutive days (72 hours) with CGMS, the first complete 24 hour dynamic glucose, which start at 3 to 5 am(corresponding to Lung) and end at 1 to 3 am next morning(corresponding to Liver), are used for calculating each two-hours?? Hurst index. The measurement data was set at each two-hours, and multiple groups of related sample tests (Friedman) non- parametric test methods were used for comparison between groups. The statistical significance level was set to P ＜ 0.05. The results showed that the Hurst indices of each two-hour are all greater than 0.5. The three highest Hurst indices were: Stomach Hurst (0.960) ＞ Heart Hurst (0.946) ＞ Spleen Hurst (0.945), and the three lowest Hurst indices were: Lung Hurst (0.886) ＜ Liver Hurst (0.893) ＜ Large intestine Hurst (0.905). The standard deviation of the large intestine Hurst was the largest, reaching 0.088, and the standard deviation of the gastric Hurst was the smallest, 0.058. The distribution image of the Hurst index of individual patients at each twohours was similar to that obtained by the whole sample, but the specific time to a certain two-hours had fluctuations. The number of pairs with statistical difference between each two groups in two-hours is 29, accounting for 44％ of the total number of pairs. The organs and meridians that have more differences with other two-hours are successively stomach, lung, liver, kidney, spleen and heart. The differences of the blood glucose changes at different times in patients with type 2 diabetes can be indicated by the dynamic blood glucose Hurst indices, which are calculated according to the rule of Qi and blood flow.

Recognizing Ventricular Tachycardia and Fibrillation with Hurst Index / 航天医学与医学工程

Objective To recognize normal sinus rhythm (NSR), ventricular tachycardia (VT) and ventricular fibrillation (VF) from each other accurately and promptly. Methods A nonlinear descriptor based on multi-scale analysis, Hurst index, as a feature to quantify the nonlinear dynamics behavior of the ECG signal, was quoted in this paper. Results The nonlinear technique, Hurst index was examined and evaluated with ECG signals extracted from MIT-BIH Arrhythmia Database, MIT-BIH Malignant Ventricular Ectopy Database, and CU Ventricular Tachyarrhythmia Database under a specific moving-window length. The experiment showed good performance of this nonlinear descriptor. When the window length was 5 s long, the recognition accuracy for each of NSR, VT and VF was 100%. Besides, the computing speed was much faster than the speed obtained with a traditional non-linear technique, the complexity measure algorithm. Conclusion The Hurst index has a strong potential for life-threatening ventricular arrhythmia recognition in clinical applications.