Clinical application of acupuncture-moxibustion for the treatment of spirit based on approximate entropy of electrooculogram signal / 中国针灸

According to the theory of acupuncture-moxibustion for the treatment of spirit, starting from the relationship between eye movement and spirit, the application of electrooculogram (EOG) signal acquisition and analysis technology for the clinical treatment of spirit by acupuncture-moxibustion is discussed. Based on the nonlinear dynamic characteristics of EOG signals, it is proposed to apply the approximate entropy algorithm to extract the EOG signal characteristics in autism spectrum disorder children under different behavior states, which could realize the preliminary exploration of the correlation between EOG signals and cognitive activities. This could provide a possibility to objectively reflect the patient' s current mental state, and could be used as a potential method to grasp spirit in clinical acupuncture- moxibustion treatment. Furthermore, considering the characteristics of acupoint stimulation on the body surface, the EOG signal acquisition and analysis technology could further be combined with biofeedback technology, and a new idea for clinical acupuncture-moxibustion to treat spirit guided by biofeedback of EOG is proposed.

Non-linear analysis of heart rate variability during deep breathing at 0.1 Hz frequency

Background: Heart rate variability (HRV) analysis is an important tool to assess the cardiac autonomic regulation in health and disease. Time-domain and frequency-domain analyses are linear methods that are traditionally used for HRV analysis. Application of non-linear methods in HRV analysis has been shown to provide additional information and has been found to be useful in predicting complications and mortality in cardiovascular disease conditions. HRV analysis during deep breathing is commonly used to assess the integrity and extent of the parasympathetic control of the heart. Aim and Objectives: This study aims to analyze the HRV during deep breathing at 0.1 Hz frequency, 6 breaths/minute using non-linear methods and to see whether they correlate with the time-domain measures of HRV. Materials and Methods: Twelve healthy volunteers performed deep slow breathing at 0.1 Hz frequency for 5 min following recorded prompts. In the time domain, mean heart rate (MHR), SDNN, RMSSD, and pNN50 during baseline and deep breathing were measured. In the non-linear domain, approximate entropy (AppEn), sample entropy (SampEn), and detrended fluctuation analysis DFA (?1) were calculated. The quantitative measures of the Poincare plot, namely, SD1, SD2, and SD2/SD1, which are known to provide linear information, were also estimated. Wilcoxon’s signed-rank test was used to compare the baseline parameters with those of deep breathing. Spearman’s correlation was used to assess the correlation between the parameters obtained from the different methods. Results: There was no significant change in the MHR, RMSSD, pNN50, and SD1 during 0.1 Hz deep breathing while SDNN, SD2, SD2/SD1, and DFA?1 showed a significant increase. Furthermore, 0.1 Hz breathing decreased the AppEn and SampEn measures of HRV. There was a strong correlation among SDNN, RMSSD, pNN50, SD1, SD2, SD2/SD1, and DFA?1, but there was no correlation between any of the above measures and the non-linear measures AppEn and SampEn. Conclusion: While the non-linear measure DFA?1 correlates well with time domain measures of HRV and the quantitative measures of the Poincare plot during 0.1 Hz breathing, AppEn and SampEn do not show such correlation. Instead, they decrease significantly when breathing is voluntarily controlled at 6 breaths/min.

Comparison between approximate entropy and regional homogeneity for identification of irritable bowel syndrome based on functional magnetic resonance imaging / 南方医科大学学报

OBJECTIVE@#To compare the effectiveness and sensitivity of entropy and regional homogeneity (ReHo) for identifying irritable bowel syndrome (IBS) based on functional magnetic resonance imaging (fMRI).@*METHODS@#Voxel-based approximate entropy (ApEn) was calculated based on findings of resting fMRI of 54 patients with IBS and 54 healthy control subjects. Feature selection was performed using independent sample -test, and support vector machine was then used to classify and identify different groups. The classification performance obtained from ApEn was compared with that from ReHo.@*RESULTS@#Significant differences between the two groups were found in the left triangle part of inferior prefrontal gyrus, right angular gyrus of the inferior parietal lobule, left inferior temporal gyrus, left middle temporal gyrus, left lingual gyrus, bilateral middle occipital gyrus and bilateral superior occipital gyrus for ReHo ( < 0.05), and in the bilateral postcentral gyrus, right precentral gyrus, right inferior temporal gyrus, bilateral middle temporal gyrus and left superior occipital gyrus for ApEn ( < 0.05). ApEn consistently showed better performance than ReHo regardless of the variations in the number of features. The classification accuracy, specificity and sensitivity of ApEn were 93.5185%, 90.7407% and 96.2963%, respectively, as compared with 86.1111%, 85.1852% and 87.037% of ReHo.@*CONCLUSIONS@#Entropy analysis based on fMRI can be more sensitive and effective than ReHo for identification of IBS.

Analysis on Insomniac Electroencephalogram Data After Treatment with Superficial Needling Based on Approximate Entropy and Correlation Dimensionality / 针刺研究

OBJECTIVE: To evaluate the influence of superficial needling on electroencephalogram (EEG) in patients with insomnia by using nonlinear kinetics measure. METHODS: Six patients (3 male and 3 female) suffering from insomnia for more than a month were recruited in the present study. EEG data before and during superficial acupuncture stimulation of Shangen point (the midpoint between the bilateral inner canthus) was recorded using an electroencephalograph for analyzing the correlation dimensionality (D 2) and approximate entropy (ApEn) of different cerebral regions. RESULTS: During superficial needling, the D 2 data of the right-forehead (Fp 2), anterior area of the left temple (F 7) and the anterior region of the right temple (F 8) were significantly increased (P<0.05), and ApEn data at the right anterior forehead(Fp 2), left occipital region (O 1), and F 8 region markedly decreased relevant to pre-acupuncture (P<0.05). Both paring test and trend analysis of D 2 data showed no significant changes. Only an obvious increase of D 2 was found in the Fp 2 region, suggesting a coherence of EEG activities in stability and synchronization during acupuncture treatment. Clustering analysis of D 2 data of various cerebral regions displayed a relatively concentrated tendency, particularly in the Fp 2, the right forehead (F 4) and F 8 regions. Factor analysis of ApEn data showed a significant change in Fp 2, F 8, O 1 and right occipital (O 2) regions. It suggests that during superficial needling stimulation of Shangen point, the EEG signals were lowered in complexity, and improved in synchronization, stabilization and ordering, favoring sleep at last. CONCLUSION: Superficial needling of Shangen point can make the EEG signals synchronized in insomnia patients, suggesting an improvement of sleeping.

Evaluación de la Presencia de Disautonomía en Pacientes con Parkinson mediante el Análisis de Señales Cardiovasculares / Assessment of the Dysautonomia Presence in Parkinson disease through Cardiovascular Signal Analysis

Resumen: En este trabajo se evalúa y compara la respuesta del sistema nervioso autónomo (SNA) en pacientes con enfermedad de Parkinson (EP) y sujetos sanos para detectar la posible presencia de disautonomía. Las señales de electrocardiograma y fotopletismografía fueron adquiridas durante las maniobras: reposo, cambio de postura (Post-CP), respiración controlada (RC) e hiperventilación (Hip.). El análisis de las señales incluyó índices de la variabilidad de la frecuencia cardiaca (VFC) lineales y no lineales, índices de la señal de tiempo de tránsito de pulso y la sensibilidad del barorreflejo (índice α). Los pacientes con Parkinson mostraron una alteración en la modulación simpática principalmente durante Post-CP y una deficiencia en la respuesta cardiovagal en RC. La entropía aproximada disminuyó significativamente en sujetos sanos respecto a pacientes con EP durante RC. El índice α fue menor en pacientes con EP con respecto a sujetos sanos durante todo el protocolo, lo cual sugiere una alteración en el control del barorreflejo en EP. Sin embargo, es necesario aumentar el número de sujetos con la finalidad de determinar grados de disautonomía. El protocolo diseñado para evaluar la presencia de disautonomía en mexicanos con EP a través de señales no invasivas aportó información sobre el comportamiento del SNA.

Abstract: The goal of this work is to assess and to compare the autonomic nervous system (SNA) response in Parkinson's disease (EP) patients and healthy subjects in order to evaluate the possible dysautonomia presence. Electrocardiogram and photoplethysmography signals were acquired during the following maneuvers: rest, orthostatic change (Post-CP), controlled breathing (RC) and hyperventilation (Hip.). The signal processing was carried out by means of linear and no linear indices of heart rate variability (VFC), indices of pulse transit time (PTT) and baroreflex sensitivity (α index). Parkinson disease patients showed an attenuated sympathetic modulation mainly during Post-CP and the cardiovagal response resulted blunted during RC. Approximate entropy was significantly decreased in healthy subjects with respect to EP subjects during RC. In addition, the index α resulted in lower values in EP patients with respect to healthy subjects during the complete protocol, this result suggests that the baroreflex control in EP patients is blunted. However, is necessary to increase the number of subjects with the objective of determining levels of dysautonomia. The protocol designed to evaluate the dysautonomia presence in mexicans with EP through non invasive signals provides information about the SNA behavior.

IDENTIFICACIÓN DE ZONAS SUSCEPTIBLES DE ABLACIÓN EN FIBRILACIÓN AURICULAR PERMANENTE IMPLEMENTANDO ENTROPÍA APROXIMADA EN UN MODELO 2D / IDENTIFICATION OF TARGET SITES FOR ABLATION DURING PERMANENT ATRIAL FIBRILLATION IMPLEMENTING APPROXIMATE ENTROPY IN A 2D MODEL / IDENTIFICAÇÃO DE ÁREAS SUSCETÍVEIS DE ABLAÇÃO PERMANENTE DE FIBRILAÇÃO ATRIAL NA IMPLEMENTAÇÃO ENTROPY APROXIMADO UM MODELO 2D

La fibrilación auricular (FA) es la arritmia cardiaca más común. La ablación con catéter se ha convertido en la principal estrategia terapéutica para el tratamiento de la FA paroxística, sin embargo, los resultados en FA permanente no son completamente satisfactorios. Se propone la ablación de los electrogramas auriculares complejos fragmentados (CFAE) para la terminación de un rotor como mecanismo de mantenimiento de FA permanente. El objetivo de este trabajo es caracterizar los CFAE mediante la implementación de entropía aproximada (ApEn) y correlacionarlos con el tip de un rotor simulado. Para esto, se desarrolló un modelo 2D de tejido de aurícula humana bajo condiciones de FA permanente; se registraron electrogramas unipolares durante la actividad del rotor y se desarrolló un algoritmo para la medida de ApEn. La ApEn permitió localizar los CFAE con una alta precisión y relacionarlos con el tip del rotor. Por lo que este índice podría ser muy eficaz en la identificación de zonas susceptibles de ablación.

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Catheter ablation has become the main therapeutic strategy for the treatment of paroxysmal AF, however, results in permanent AF are not completely satisfactory. Ablation of complex fractionated atrial electrograms (CFAE) is proposed for the termination of a rotor as mechanism of permanent AF maintenance. The aim of this work is to characterize the CFAE by implementing approximate entropy (ApEn) and to correlate with the tip of a simulated rotor. For this, a 2D model of human atrial tissue under permanent FA conditions was developed. Unipolar electrograms were recorded during the rotor activity and an algorithm to measure ApEn was developed. The ApEn allowed locate the CFAE with high precision and relate them to the tip of the rotor. So this index could be very effective in identifying target sites for ablation.

A fibrilação atrial (FA) é a arritmia cardíaca mais comum. A ablação por cateter tornou-se a principal estratégia terapêutica para o tratamento da fibrilação atrial paroxística, no entanto, resulta em FA permanente não são completamente satisfatórios. Ablação de fones de ouvido eletrocardiogramas complexos fragmentada (CFAE) para a conclusão de um rotor como um mecanismo de manutenção da FA permanente, é proposto. O objetivo deste trabalho é caracterizar o CFAE através da implementação de entropia aproximada (ApEn) e correlacioná-los com a ponta de um rotor simulado. Para isso, um modelo em 2D do tecido atrial humano sob condições de FA permanente desenvolvido; unipolares electrogramas foram registados durante a actividade do rotor e um algoritmo para medir ApEn desenvolvido. O ApEn permitido CFAE localizar com precisão elevada e relacioná-los com a ponta do rotor. Portanto, esta taxa pode ser muito eficaz na identificação de áreas suscetíveis a ablação.

Changes in EEG approximate entropy of frontal lobes induced by sustained perform-ance / 军事医学

Objective To explore the effect of sustained performance on EEG approximate entropy (ApEn).Methods Fifty participants were divided into two groups according to whether they had undergone sustained performance .One day af-ter the sustained-performance group finished executing their task , the resting EEG of nine electrodes ( F3, Fz, F4, C3, Cz, C4, P3, Pz and P4) was acquired in two grups separately , and the ApEn of each electrode was calculated as well . Results The ApEn of F3 and Fz showed an evident decrease as well as randomness of spontaneous brain electrode activity in frontal lobes , especially in the left one .Conclusion The drop of ApEn and the asymmetry of frontal lobes might reflect participants′state of fatigue during sustained performance .

Approximate entropy of oxygen saturation and saturation impairment time index for the assessment of hypoxemia severity in obstructive sleep apnea hypopnea syndrome / 中华内科杂志

Objective To explore the clinical significance of two new indexes including approximate entropy of oxygen saturation (SpO2ApEn) and saturation impairment time index (SITi) in assessing the severity of hypoxemia in obstructive sleep apnea hypopnea syndrome (OSAHS) patients.In addition,to investigate the correlation betewwn new indexes and other parameters.Methods The six hour polysomnography (PSG) of 500 patients with OSAHS and snorers in our hospital was retrospectively analyzed.According to the level of apnea hypopnea index (AHI),subjects were divided into four subgroups,namely 113 healthy controls,121 mild OSAHS,118 moderate OSAHS,and 148 severe OSAHA patients.SpO2 ApEn and SITi values among the four groups were compared.the correlations between SpO2 ApEn,SITi and other parameters were analyzed,including AHI,oxygen desaturation index (ODI),the lowest oxygen saturation(LSpO2) and the duration of oxygen saturation lower than 90％ (T ＜ 90％).Next,taking AHI as the gold standard,the significance of SpO2ApEn and SITi in assessing the severity of hypoxemia in OSAHS patients was explored by ROC curve analysis.Results SpO2ApEn and SITi between two each groups were significantly different (P ＜ 0.001) and increased synchronously with AHI.Spearman correlation analysis showed that SpO2ApEn and SITi had a good correlation with AHI (correlation coefficient r =0.765,r =0.678,P ＜ 0.O1).SpO2ApEn and SITi also had a good correlation with ODI,LSpO2and T ＜ 90％.According to the ROC analysis,the Boundary values of SpO2ApEn for mild,moderate and severe OSAHS patients were 16.70,17.81,and 20.03,respectively,and the corresponding SITi values were 3.685,4.055,and 4.445.Conclusion In this study,SpO2ApEn and SITi increased synchronously with AHI,SpO2ApEn and SITi had good correlations with AHI,ODI,LSpO2and T ＜90％.SpO2ApEn and SITi have important clinical significance for assessment of hypoxia severity in OSAHS patients.

Componentes de variância genética e ambiental nos padrões de atividade física de gêmeos. Exploração das possibilidades da entropia aproximada / Genetic and environmental variance components for physical activitypatterns of twins. Exploring the possibilities of approximate entropy

O principal objetivo deste estudo foi estimar a contribuição dos fatores genéticos no padrão da atividade física (AF) de gêmeos através da estatística entropia aproximada (EA). A amostra foi constituída por 162 pares de gêmeos monozigóticos (MZ) e dizigóticos (DZ) com idade entre seis e 18 anos, residentes em Portugal. A AF foi medida pelo acelerômetro Tritrac-R3D durante cinco dias de uma semana habitual. Para descrever o padrão da AF, recorreu-se a descrição da EA estimada através do software Cine Wizard. A determinação da zigotia foi realizada com base no método direto de análise do DNA. Para a análise dos dados,foram utilizados diferentes softwares como SYSTAT 10.0, STATA 10,0 e o Twinan92. A EA foi calculada para três diferentes fenótipos de AF, classificados de acordo com a quantidade de dias de mensuração (EA 5, 3 e 2 dias). Foi utilizado o recurso a modelos distintos paradescrever o padrão das matrizes de covariância entre pares de gêmeos (variância genética, envolvimento comum e único) e o nível de significância foi fixado em 5%. Foi verificada a presença de agregação fraterna na EA com uma maior homogeneidade entre os gêmeosMZ. Pode-se concluir que os fatores genéticos apresentaram forte influência, na variação interindividual, no padrão de AF e sua contribuição variou entre 44 e 89%.

The main objective of this study was to estimate the contribution of genetic factors to physical activity patterns (PAPs) in twins using approximate entropy (ApEn) statistics. The sample consisted of 162 monozygotic and dizygotic twins from Portugal aged 6 to 18 years. Physical activity was measured with a Tritrac-RT3 triaxial accelerometer over 5 days of a usualweek. PAPs were described by ApEn using the Cine Wizard software. Zygosity was assessed by direct DNA analysis. Data were analyzed using the SYSTAT 10, STATA 10 and Twinan92 softwares. PAPs were estimated for 5, 3 and 2 days. In addition, structural equation modelingwas used to compute different sources of variance genetic, common environmental and unique environmental variance.The level of significance was set at 5%. Sibling aggregation was identified by ApEn analysis, with monozygotic twins showing greater homogeneity. In conclusion, geneticfactors accounted for 44 to 89% of the total variation in PAP.

Observation of cortical electrical activation during aphasic recovery with EEG approximate entropy / 中国康复医学杂志

Objective: ①To study whether changes of cortical electrical activations in two hemispheres correlated with speech tasks could be observed with approximate entropy analysis of EEG; ②To dynamically observe the correlation of speech improvements with cortical electrical activations in two hemispheres during speech treatment. Method: Changes of cortical electrical activations were observed with EEG in a conductive aphasic 7、9 and 30 weeks after stroke. EEG was recorded in 3 different conditions: eyes closed, word repetition and non-word repetition. The EEG of a healthy man was recorded in 3 different conditions as control. Result: Compared with eye-closed condition, EEG approximate entropies(ApEn_s) of the healthy subject increased in T3, T5, C3, P3 and O1 for word and non-word repetition, and additional F7 and T6 for non-word repetition task. For the patient, ApEn of the first EEG increased in P3 for word repetition, and P4 for non-word repetition; ApEns of the second EEG increased in F3, F7, P3, C3, C4,T3, T5, O1, and decreased in F8, T4 and O2 in right hemisphere for word and non-word repetition; ApEns of the third EEG increased in T3, P3, F7, O1, O2 for word repetition,and T3, O2 for non-word repetition. The first aphasia assessment showed light impairment of semantic system and initial sound auditory identification and severely impairment of picture naming and word repetition. The semantic system and initial sound auditory identification improved significantly in the second assessment compared with the first; but the word repetition remained unchanged. The range of the activated regions in the left hemisphere decreased in the third EEG compared with the second EEG and the activated regions were less than the normal subject. Conclusion: The cortical electrical activities correlated with repetition tasks and the change of cortical electrical activities in different stages of language recovery could be observed with EEG nonlinear analysis.

The Theory of Approximate Entropy and its Application / 中国医学物理学杂志

Objective: To introduce the advantages of approximate entropy (ApEn) in analyzing biological signals, to discuss the influences of time series' parameters on ApEn and elaborate the present conditions and prospects of its application on medicine. Methods: According to the definition and algorithm, ApEn has advantages on estimating the complexity of signal comparing with other non-linear analysis methods such as correlation dimension, fractal dimension, lyapunov index etc. Based on ApEn algorithm, we formulate programme to quantificationlly analyze the relationship between ApEn and each parameter of time series; Human EEG and ECG and other biological signals can reflect the state of the body. Through detecting changes of biological signals'ApEn, we can detect and monitor the state of an organization. Results: ApEn has many advantages such as a good anti-noise ability, the short date and so on. It makes up the defects of the correlation dimension ect. ApEn has nothing with the amplitude of time series. In the range of low-frequency, ApEn almost increases with frequency. When the date length is more than 1000 points, ApEn is stable. It quantificationlly describes that ApEn only requires short date. Recently. ApEn is widely used in diagnostics, monitoring, anesthesiology, and achieves good results. Conclusion: ApEn is a new developed non-linear analysis method which can estimate the complexity of the signal quantificationlly. It provides a new approach for diagnosing and monitoring a number of diseases. It has a wide application prospect.

Approximate entropy as the measurement of the electroencephalographic effect during sevoflurane induction / 대한마취과학회지

BACKGROUND: The processed electroencephalograms are useful surrogate measures of quantification of volatile anesthetics effect. We hypothesized that there is a certain relationship between the end-tidal concentration of sevoflurane and approximate entropy (ApEn). The aim of this study was to investigate the effect of sevoflurane on ApEn during induction. METHODS: Fourteen patients were enrolled. With recording of the electroencephalogram at the F3, F4, P3, and P4 montages, anesthesia was induced by increasing the vapor setting of sevoflurane by 1 vol% up to 8 vol% via a facemask. When the end-tidal concentration of sevoflurane did not show any further change, we increased vapor setting of sevoflurane by 1 vol%. When the end-tidal concentration of sevoflurane did not show any further change with 8 vol% of sevoflurane vapor setting, measurement of electroencephalogram was finished. The relation between end-tidal sevoflurane concentration and ApEn was tested by Spearman correlation. RESULTS: ApEn showed a significant correlation (R = -0.7551, P < 0.0001) with end-tidal sevoflurane concentration. The final pharmacodynamic parameters estimated by a sigmoid E(max) model were described as follows: E(0) = 0.91, E(max) = 0.28, C(e50) = 1.36 vol%, gamma = 1.27, kappa(e0) = 0.67 min(-1). CONCLUSIONS: Sevoflurane induction with gradual increase of end-tidal sevoflurane concentration increases the amount of regularity in approximate entropy.

EFFCT OF WALKING SPEED ON THE COMPLEXITY OF THE CYCLE OF HEAD FLUCTUATION DURING WALKING USING APPROXIMATE ENTROPY / 体力科学

The purpose of this study is to show clearly whether the complexity of the cycle of head fluctuation during walking is influenced with walking speed. Thirty young healthy males and females volunteered as subjects for this study. Subjects walked 40 m, and they were instructed to walk “slowly”, “a little slowly”, “usual speed”, “a little fast” and “fast” depending on their subjectivities. The head fluctuation of the right-and-left direction during a walk was measured by using an accelerometer. In addition, the complexity of the head fluctuation of the right-and-left direction cycle was calculated by utilizing Approximate Entropy (ApEn). After the value of ApEn was standardized at the walking speed, each walking speeds were compared. As a result, the value of ApEn increased at the slowly speed, and decreased with the increases in the walking speed. And the value of ApEn showed plateau or decrease at a little faster than free walking speed. From our results, it thought a possibility that Central Pattern Generator is optimized at the free walking speed. In conclusion, it is clear that walking speed have influenced on the complexity of the walking cycle.

Peri-ictal complexity loss as determined by approximate entropy analysis in the electrocorticogram obtained from chronic subdural recordings in patients with refractory temporal lobe epilepsy

RATIONALE: The development of closed-loop devices suitable for use in the treatment of epileptic patients would very likely rely on the adequate development of paradigms able to forecast the occurrence of seizures. In this paper, we studied the usefulness of approximate enthropy, of a non-linear paradigm, in this patient population. METHODS: We applied approximate entropy (ApEn) analysis to study the variability in the complexity of the peri-ictal electrocorticogram (ECoG) of patients with refractory epileptic seizures of the temporal lobe origin. Three patients were implanted with chronic subdural grids. The ApEn algorithm measured the complexity of interictal, peri-ictal and ictal phases. We selected one representative channel disclosing interictal activity for each patient and two channels per patient with ictal recordings. RESULTS: In all patients, we found one channel where the interictal activity registered in the ECoG was associated with high complexity and where ApEn was higher than 0.59. But in the other two channels, for each patient that presented interictal/ictal transitions, clinical manifestations of epileptic seizures occurred around 3.5 seconds after the entropy drop, when entropy was below 0.5. In contrast, when entropy was higher than 0.5, clinical manifestation occurred 9.5 seconds after the entropy drop. The 3.5 seconds shorter delay possibly indicates focal activity in the channel analyzed. CONCLUSIONS: Our results suggest that ApEn may be a useful instrument for early detection of epileptic activity. Its application may be indicated for prevention and diagnosis of epileptic seizures.

RACIONAL: O desenvolvimento de aparatos retroalimentáveis para o tratamento de pacientes epilépticos dependerá em grande parte do desenvolvimento adequado de paradigmas que possam antever as crises. Neste trabalho, estudamos a utilidade da entropia aproximada (ApEn), um paradigma não-linear, em pacientes portadores de epilepsia. MÉTODOS: Aplicamos a análise de entropia aproximada (ApEn) no estudo de variabilidade da complexidade do eletrocorticograma (ECoG) de pacientes com epilepsia refratária com origem no lobo temporal. Três pacientes foram implantados com matrizes de eletrodos subdurais. O algoritmo ApEn mediu a complexidade das fases interictal, peri-ictal e ictal. Selecionamos um canal representativo de cada paciente manifestando atividade interictal e dois canais de cada paciente com registro ictal. RESULTADOS: Em cada paciente, encontramos um canal cuja atividade interictal registrada no ECoG foi associada a alta complexidade com ApEn maior que 0.59. Nos outros dois canais, para cada paciente que apresentou transição interictal/ictal, as manifestações clínicas das crises epilépticas ocorreram cerca de 3.5 segundos depois após a queda da entropia abaixo de 0.5. Em comparação, quando a entropia foi maior que 0.5, as manifestações clínicas ocorreram 9,5 segundos após a queda da entropia. A curta latência (3.5 segundos) indicou possivelmente o local de início da atividade focal. CONCLUSÕES: Nossos resultados sugerem que ApEn pode ser um instrumento útil na detecção precoce da atividade epiléptica. Sua aplicação pode estar indicada na prevenção ou diagnóstico das crises epilépticas.

Research on Nonlinear Characteristic of ECG Signals and Tone of Autonomic Nervous System during Water-immersion Restraint Stress in Rats / 航天医学与医学工程

Objective To definite the status of tone of autonomic nervous system during water immersion process by analyzing the nonlinear characteristic of ECG signals;To explore the relation of approximate entropy(ApEn),scaling exponent(?) changes and modulation function status of autonomic nervous system.Methods The ECG signals of rats during the process of restraint stress(RS),water-immersion restraint stress(WRS) and Vagotomy and Water-immersion restraint stress(vagotomy-WRS) were recorded.The ApEn and ? of RR intervals were calculated.Results After the stress,the differences of the value of ApEn and ? of RR intervals between RS and vagotomy-WRS groups and between different periods in vagotomy-WRS group were not significant.The value of ApEn increased in WRS group and decreased in RS group significantly.Compared with pre-stress,? showed decreased trend,all of the values smaller than 0.5 in WRS group and increased obviously,most values larger than 0.5 in RS group.Conclusion The increased ApEn and decreased ? indicates a higher intensity of parasympathetic activity.The parasympathetic activity is the predominant response of autonomic nervous system during water immersion process.

The Approximate Entropy in Maternal Anemia during Pregnancy according to Gestational Age / 대한주산의학회잡지

OBJECTIVES: Maternal anemia is common hematologic disorders during pregnancy. Although mild maternal anemia is not associated with fetal anemia, neonatal morbidity including fetal anemia are common with severe maternal anemia during pregnancies. We aim to analyze each variable of FHR using linear and nonlinear methods to detect maternal anemia during pregnancies. METHODS: Seventy antepartal anemic pregnant women(Hb<10.0g/dL) and the contrast group, 70 normal pregnant women were selected among the women who underwent nonstress test(NST) during 3rd trimester in Hanyang University Hospital. The calculated FHR parameters(NST time=20 min) from collected FHR data(40-50min) were made by HYFM II data file. To assess the difference between the anemic and normal pregnancy group, the parameters such as baseline FHR, variability (AMP, MMR), acceleration and deceleration(15bpm-15seconds), gestational age at the time of NST, loss of record, the number of fetal movement, FHR were evaluated. We compared the canonical correlation between each groups using variables of NST. The overall complexity of each FHR time series was quantified by its approximate entropy(ApEn), measure of regularity derived from nonlinear dynamics, "chaos theory". Finally we extract the value of ApEn and were compared between two groups, normal and anemic pregnant women. RESULTS: There were significant decrease of FHR variability(amplitude and mean minute interval) in anemic group. Canonical correlation ensemble was significantly high in 36th-37th and 38th-39th gestational weeks in anemic group(p-value=0.03048 and 0.03421). The value of ApEn was significantly low(0.68+0.26) in anemic group comparing with normal pregnant group(0.95+0.08), respectively. CONCLUSIONS: This study shows that FHR of maternal anemia is different from that of normal pregnant women, and that subtle behavioral differences could be demonstrated in uterus using computerized FHR analysis. The anemic women during pregnancy have more linear and less complicated FHR than the normal pregnancy group. ApEn, which is bound to be used as an index of fetal well-being would be used as an evaluating tool of intrauterine fetal function in the near future.

Approximate Entropy of the Short-term Variability of Fetal Heart Rate as an Efficient Measurement of Fetal Distress / 대한산부인과학회잡지

OBJECTIVE: The purpose of this study was to evaluate the usefulness of approximate entropy on fetal heart rate variability of electronic fetal monitoring taken during antepartum and intrapartum periods as a new diagnostic method of fetal distress. METHODS: Among 76 pregnant women who underwent computerized electronic fetal monitoring and cord blood gas analysis, we divided them into 3 groups, i.e.; 36 into normal fetus group, 26 into presumed distress group and 14 into acidemic distress group. We performed a frequency analysis on time series of heart rate variability in three groups. In order to perform non-linear analysis on the raw data of the fetal heart rate, after resampling and low pass filtering, we investigated approximate entropy. RESULTS: The results of the approximate entropy showed that the value in normal fetus group was significantly high than the value in distress group. But in the distress group, ApEn value was not difference between acidemic and non-acidemic subgroup. ApEn of HRV was confirmed in nonlinear parameter without low pass filtering and resampling. CONCLUSION: The results show that the fetal heart rate variability has nonlinear characteristics and could distinguish normal fetal heart rate pattern and distress pattern numerically and objectively. And these ApEn value are useful for prediction and diagnosis of fetal distress in ante and prenatal periods.

Analysis of Heart Rate Variability in Preoperative Diabetic Patients by Linear and Nonlinear Dynamics / 대한마취과학회지

BACKGROUND: The aim of this study was to investigate the underlying changes in heart rate variability (HRV) of preoperative diabetic patients using five analytical methods; SDNN (standard deviation of normal to normal intervals), SDANN (standard deviation of the mean of normal RR intervals for each 5 min period of the entire electrocardiographic recording), RMSSD (root mean square successive difference, the squre root of the mean of the sum of the squares of differences between adjacent normal RR intervals over the entire electrocardiographic recording), PNN50 (percent of difference between adjacent normal RR intervals that are greater than 50 ms computed over the entire electrocardiographic recording) for linear time domain analysis and approximate entropy for nonlinear complexity analysis. METHODS: HRV values analyzed by five different measures were compared between a control group of ten nondiabetics without any significant systemic disease and a diabetic group of ten patients from the preoperative ambulatory electrocardiographic recordings. RESULTS: Approximate entropy, SDNN and SDANN values were significantly lower in the diabetic group than those of the control group (P< 0.01). CONCLUSIONS: Significantly decreased approximate entropy, SDNN and SDANN could provide information about decreased cardiovascular complexity and sympathetic output, suggesting the nature of dysfunction of the diabetic cardiovascular system.

Linear and Nonlinear Analysis of Heart Rate Variability in Postoperative Myocardial Ischemic Patients: Time Domain Analysis versus Approximate Entropy / 대한마취과학회지

BACKGROUND: Postoperative myocardial ischemia has been regarded as one of the major predictors of adverse cardiac outcomes after noncardiac surgery in high risk patients. Many schemes have been proposed to stratify the potential risk of this patient group in more noninvasive and cost-effective ways and analysis of heart rate variability (HRV) is one of them. To uncover the underlying changes in HRV with postoperative myocardial ischemia five analytical methods were introduced; SDNN (standard deviation of normal to normal intervals), SDANN (standard deviation of the mean of normal RR intervals for each 5 min period of the entire electrocardiographic recording), RMSSD (root mean square successive difference, the squre root of the mean of the sum of the squares of differences between adjacent normal RR intervals over the entire electrocardiographic recording), PNN50 (percent of difference between adjacent normal RR intervals that are greater than 50 ms computed over the entire electrocardiographic recording) for linear time domain analysis and approximate entropy for nonlinear complexity analysis. METHODS: Sixteen vascular surgical patients were monitored by an ambulatory electrocardiogram preoperatively and during the first postoperative day (POD1). HRV values analyzed by five different measures were compared between a control group (C group) of eight patients with no postoperative ischemia and a postoperative ischemic group (PI group) of eight with ischemia on POD1. RESULTS: Approximate entropy was the only measure of HRV which was significantly lower in PI group than that of C group (P< 0.01) on POD1. CONCLUSIONS: Approximate entropy, a complexity measure could provide more sensitive information about the physiologic changes associated with postoperative ischemia which could not be obtained from the conventional HRV measures. Time domain analyses can be used as adjuvant measures providing information about the cardiac autonomic regulation.

The analysis of FHR parameters, approximate entropy and canonical correlation of fetuses with mild baseline tachycardia / 대한산부인과학회잡지

OBJECTIVE: This study was to determine differences of fetal heart rate (FHR) parameters, approximate entropy, canonical correlation coefficient and perinatal outcome between fetuses with mild baseline tachycardia (FHR range : 161-180 bpm) and fetuses with normal baseline FHR. METHODS: Using our own software developed by Hanyang University Hospital in Korea, non-stress tests were performed for 20 minutes and cases were divided into two groups; mild tachycardia group (FHR range ; 161-180 bpm, 100 cases) and normal group (FHR ranges ; 120-160 bpm, 197 cases). And then, we analyzed various FHR parameters, approximate entropy, adjusted canonical correlation coefficient and perinatal outcome in each group. RESULTS: Perinatal outcomes between two groups were not significant. However, mean minute range (MMR) was lower and the number of deceleration (15 bpm for 15 sec, more than one) was significantly higher in fetuses with mild tachycardia than normal group (p<0.05). The apprximate entropy and canonical correlation coefficient showed respectively 0.77+/-0.02, 0.45+/-0.06 in mild tachycardia group and 0.80+/-0.01, 0.43+/-0.07 in normal group, there were no significant differences. CONCLUSIONS: The results showed that mild baseline tachycardia in this range were not associated with an increase in the incidence of adverse perinatal outcome, although decreased MMR and increased number of deceleration in mild tachycardia group may suggest hidden subtle change of FHR parameters. Fetuses with mild tachycardia were not different irregularity of FHR quantified by approximate entropy from normal fetuses and were also similar tendency to correlation with perinatal outcome by adjusted canonical correlation coefficient, which is a multivariate extension of the univariate correlation analysis.