Alfonsas Vainoras

Nonlinear dynamics analysis of electrocardiograms for detection of coronary artery disease

A computerized approach of nonlinear dynamics analysis of electrocardiogram (ECG) signals was applied for the detection of coronary artery disease (CAD). The proposed nonlinear dynamics descriptors were derived from 12-lead rest ECG data, and evaluated by originally developed computer software. Fluctuations of potentials of ECG leads that occur during the period of 20 ms with a magnitude of 5-20 microV were significantly less beat-to-beat predictable in ischemic versus non-ischemic patients. The well-known nonlinear dynamics descriptors, recurrences percentage, mutual information, fractal dimension, and a new descriptor, next embedding dimension error, were good quantitative descriptors of fluctuations. They were significantly different (< p = 0.00001) in males with (108 patients) and without (54 patients) coronary artery lesions. The analysis of small fluctuations required a careful preprocessing technique based on knowledge of specifics of measurement errors and physiology of ECG signals. We considered finite differences of measured potentials with the time step of 20 ms as the initial source for nonlinear analysis. In nonlinear dynamics analysis, we also included such time moments that only belong to P- and T-waves or baseline drift with small positive slopes that allowed us to extract, under normal conditions, initial halves of P- and T-waves that displayed a better capacity to classify ischemic patients.

Matrix analysis of human physiologic data

The new method for assessment of interpersonal and inter parameter concatenation during monitoring of vital signals has been developed. Assessment of inter parameter concatenation permitted to reveal some new features of heart functionality when ECG monitoring was performed during various situations. Proposed method and values of concatenation between various processes could serve as indicators of human functional state and also could be applied for assessment of interpersonal functional concatenation.

Identification of a Group’s Physiological Synchronization with Earth’s Magnetic Field

A new analysis technique for the evaluation of the degree of synchronization between the physiological state of a group of people and changes in the Earth’s magnetic field based on their cardiac inter-beat intervals was developed and validated. The new analysis method was then used to identify clusters of similar synchronization patterns in a group of 20 individuals over a two-week period. The algorithm for the identification of slow wave dynamics for every person was constructed in order to determine meaningful interrelationships between the participants and the local magnetic field data. The results support the hypothesis that the slow wave rhythms in heart rate variability can synchronize with changes in local magnetic field data, and that the degree of synchronization is affected by the quality of interpersonal relationships.

Synchronization of Human Autonomic Nervous System Rhythms with Geomagnetic Activity in Human Subjects

A coupling between geomagnetic activity and the human nervous system’s function was identified by virtue of continuous monitoring of heart rate variability (HRV) and the time-varying geomagnetic field over a 31-day period in a group of 10 individuals who went about their normal day-to-day lives. A time series correlation analysis identified a response of the group’s autonomic nervous systems to various dynamic changes in the solar, cosmic ray, and ambient magnetic field. Correlation coefficients and p values were calculated between the HRV variables and environmental measures during three distinct time periods of environmental activity. There were significant correlations between the group’s HRV and solar wind speed, Kp, Ap, solar radio flux, cosmic ray counts, Schumann resonance power, and the total variations in the magnetic field. In addition, the time series data were time synchronized and normalized, after which all circadian rhythms were removed. It was found that the participants’ HRV rhythms synchronized across the 31-day period at a period of approximately 2.5 days, even though all participants were in separate locations. Overall, this suggests that daily autonomic nervous system activity not only responds to changes in solar and geomagnetic activity, but is synchronized with the time-varying magnetic fields associated with geomagnetic field-line resonances and Schumann resonances.

Long-Term Study of Heart Rate Variability Responses to Changes in the Solar and Geomagnetic Environment

This long-term study examined relationships between solar and magnetic factors and the time course and lags of autonomic nervous system (ANS) responses to changes in solar and geomagnetic activity. Heart rate variability (HRV) was recorded for 72 consecutive hours each week over a five-month period in 16 participants in order to examine ANS responses during normal background environmental periods. HRV measures were correlated with solar and geomagnetic variables using multivariate linear regression analysis with Bonferroni corrections for multiple comparisons after removing circadian influences from both datasets. Overall, the study confirms that daily ANS activity responds to changes in geomagnetic and solar activity during periods of normal undisturbed activity and it is initiated at different times after the changes in the various environmental factors and persist over varying time periods. Increase in solar wind intensity was correlated with increases in heart rate, which we interpret as a biological stress response. Increase in cosmic rays, solar radio flux, and Schumann resonance power was all associated with increased HRV and parasympathetic activity. The findings support the hypothesis that energetic environmental phenomena affect psychophysical processes that can affect people in different ways depending on their sensitivity, health status and capacity for self-regulation.

Correlation between Changes in Local Earth’s Magnetic Field and Cases of Acute Myocardial Infarction

The impact of changes in the geomagnetic field on the human body remains the subject of studies across the world, yet there is no consensus. Current studies are observing effects that require further work by researchers in order to find out the mechanisms that would allow a proper assessment of the correlations between the Earth‘s magnetic field variations and changes in human organisms. The main purpose of this study was to investigate possible correlations between the strength of time-varying aspects of the local Earth’s magnetic field and incidence of myocardial infarctions. Study participants included 435 males and 268 females who had diagnosis of myocardial infarction during the period of 1 January 2016 to 31 December 2016 and attended the Department of Cardiology at the Hospital of Lithuanian University of Health Sciences (LUHS), Kauno klinikos. Time varying magnetic field data was collected at the magnetometer site located in Lithuania. After mathematical analysis, the results support the hypothesis that the Earth’s magnetic field has a relationship between the number of acute myocardial infarction with ST segment elevation (STEMI) cases per week and the average weekly geomagnetic field strength in different frequency ranges. Correlations varied in different age groups as well as in males and females, which may indicate diverse organism sensitivity to the Earth’s magnetic field.

Segmentation Algorithm for Algebraic Progressions

Segmentation task can provide important information about the nature of the sequence that is understandable to humans. A new algorithm for sequence segmentation is proposed in this paper. It is shown that it is possible to segment sequence finding a nearest algebraic progression to an each segment of a given sequence. The proposed segmentation technique based of the concept of the rank of a sequence. The rank of a sequence describes exact algebraic relationships between elements of the sequence. Numerical experiments with an artificially generated numerical sequence are used to illustrate the functionality of the proposed algorithm.

Assessment of coherence and complexity of cardiac signals

The topical subject is intensive extraction of information from cardiac signals and using it in diagnostics and assessment status of heart function. The aim of this study is presentation of the analytical method designed for analysis of dynamic interrelations between different cardiac signals — electrocardiogram, impedance cardiogram and seism-cardiogram.

New approach for visualization of relationships between RR and JT intervals

This paper presents the concept of perfect matrices of Lagrange differences which are used to analyze relationships between RR and JT intervals during the bicycle ergometry exercise. The concept of the perfect matrix of Lagrange differences, its parameters, the construction of the load function and the corresponding optimization problem, the introduction of internal and external smoothing, embedding of the scalar parameter time series into the phase plane—all these computational techniques allow visualization of complex dynamical processes taking place in the cardiovascular system during the load and the recovery processes. Detailed analysis is performed with one person’s RR and JT records only—but the presented techniques open new possibilities for novel interpretation of the dynamics of the cardiovascular system.

Independence and Hand Muscle Force Changes of the Persons After a Stroke Using Conventional and Occupational Therapy Based on Differential Learning Method

Santrauka Galvos smegenų infarktas ūminis židininis galvos smegenų kraujotakos sutrikimas, pasireiškiantis židininiais neurologiniais simptomais, išliekančiais ilgiau kaip 24 val. nuo ligos pradžios. Ergoterapijos tikslas pacientams, patyrusiems galvos smegenų infarktą, – padėti sugrįžti fizinėms, protinėms, socialinėms ir profesinėms galimybėms. Ergoterapijos tikslas pacientams, patyrusiems galvos smegenų infarktą, yra jų galimybių atgavimas, palaikymas ar sutrikimų kompensavimas tikslinga veikla, siekiant padėti savarankiškai gyventi. Diferencinio mokymo metodas – alternatyva kartotiniams judesiams. Tyrimo tikslas ištirti savarankiškumo ir plaštakos raumenų jėgos pokyčius pacientams, persirgusiems galvos smegenų infarktu, taikant įprastą ir diferencinio mokymo metodika paremtą ergoterapiją. Tyrime dalyvavo 27 pacientai, persirgę galvos smegenų infarktu, iš jų 9 vyrai (33,3 proc.) ir 18 moterų (66,7 proc.). Tiriamieji buvo 50 85 metų amžiaus (amžiaus vidurkis 72,19 m. ± 8,02). Prieš tyrimą pacientai atsitiktinės atrankos būdu buvo suskirstyti į dvi grupes: A – kontrolinė grupė, 13 pacientų (48,1 proc.), B – tiriamoji grupė, 14 pacientų (51,9 proc.). Pacientai reabilitacijos pradžioje ir pabaigoje ergoterapeuto buvo tiriami naudojant: dinamometrą, tirta dešinės ir kairės plaštakų raumenų jėga, bei Tarptautinės funkcionavimo, neįgalumo ir sveikatos klasifikacijos (TFK) skyriaus Veiklos ir dalyvumo savipriežiūros testą. Kontrolinės grupės tiriamiesiems prieš ergoterapiją savipriežiūros užduočių atlikimas buvo vidutinio sunkumo, o tiriamosios grupės pacientų – vidutinio/nedidelio sunkumo. Straipsnyje ASMENŲ, PERSIRGUSIŲ GALVOS SMEGENŲ INFARKTU, SAVARANKIŠKUMO IR PLAŠTAKOS RAUMENŲ JĖGOS POKYČIAI TAIKANT ĮPRASTĄ IR DIFERENCINIO MOKYMO METODIKA PAREMTĄ ERGOTERAPIJĄ