Hariton Costin

Cardiovascular and cardiorespiratory coupling analyses: a review.

Recently, methods have been developed to analyse couplings in dynamic systems. In the field of medical analysis of complex cardiovascular and cardiorespiratory systems, there is growing interest in how insights may be gained into the interaction between regulatory mechanisms in healthy and diseased persons. The couplings within and between these systems can be linear or nonlinear. However, the complex mechanisms involved in cardiovascular and cardiorespiratory regulation very likely interact with each other in a nonlinear way. Recent advances in nonlinear dynamics and information theory have allowed the multivariate study of information transfer between time series. They therefore might be able to provide additional diagnostic and prognostic information in medicine and might, in particular, be able to complement traditional linear coupling analysis techniques. In this review, we describe the approaches (Granger causality, nonlinear prediction, entropy, symbolization, phase synchronization) most commonly applied to detect direct and indirect couplings between time series, especially focusing on nonlinear approaches. We will discuss their capacity to quantify direct and indirect couplings and the direction (driver–response relationship) of the considered interaction between different biological time series. We also give their basic theoretical background, their basic requirements for application, their main features and demonstrate their usefulness in different applications in the field of cardiovascular and cardiorespiratory coupling analyses.

A Low Power Wireless Personal Area Network for Telemedicine

the current common goal in medical information technology today is the design and implementation of telemedicine solutions, which provide to patients services that enhance their quality of life. Recent technological advances in sensors, low-power integrated circuits, and wireless communications have enabled the design of low-cost, miniature, and intelligent physiological sensor modules. These modules are capable of measuring, processing, communicating one or more physiological parameters, and can be integrated into a wireless personal area network (WPAN). In this paper we present the realization of a wireless personal area network for patient monitoring, as a part of a telemedicine system, capable to measure and transmit physiological parameters such us blood pressure, heart rate, respiratory rhythm, pulse oximetry SpO2, body temperature, and three ECG leads. The use of WPAN is suitable for continuous long-time patient monitoring as a part of a diagnostic procedure, can achieve medical assistance of a chronic condition, or can be supervised during recovery from an acute event or surgical procedure. For instance, the computer-assisted rehabilitation involves unwieldy wires between sensors and monitoring device that are not very comfortable for normal activity. We use the intelligent wireless sensors, based on low power microcontrollers and RF transceivers that perform the measurements and computes the physiological parameters. Individual sensor monitors specific physiological parameter and communicates with the personal server. Personal server, in form of a wireless PDA that running a personal health monitor application, receives the information from wireless sensors, activates the alarms when the measured parameters are above the limits, and communicates periodically to the central server (part of the telemedicine system) by using WiFi or GSM/GPRS connection. The monitor reacts to potential health risks and records physiological information into a local database.

Automatic analysis of the fetal heart rate variability and uterine contractions

The aim of this study is the identification of the dynamic relationship between intrapartum fetal heart rate (FHR) variability and uterine pressure (UP) for normal and hypoxic fetuses. A new method for automatic analysis and identification of uterine contractions is developed and tested on 552 recordings. Using contractions, the fetal heart rate variations are established: accelerations and decelerations (early, late and prolonged). These allow a classification of the recordings analyzed into two categories: normal and pathological. The results are compared to documented fetal outcome results quantified by means of low pH and Apgar values. The developed method provides a series of quantitative measurements for the uterine contractions signal (total number of contractions, total contraction time, total percentage of contraction time, average values for contraction length, peak to peak values, area under curve). Based on these measurements we determine the Spearman correlation coefficients and the scatter matrix between the FHR and UP signals and the fetal outcome parameters: pH and Apgar scores. The correlation result show a strong relationship between decelerations presented on the FHR signal, increasing number of contractions and the low pH and Apgar values.

TELEMON - An Embedded Wireless Monitoring and Alert System for Homecare

The current common goal in medical information technology today is the design and implementation of monitoring solutions, which provide to patients services that enhance their quality of life. Developing of mobile information and communication technologies in home monitoring applications is becoming more useful. Advances in wireless sensor network technology, the overall miniaturization of their associated hardware low-power integrated circuits and wireless communications have enabled the design of low-cost, miniature, and intelligent physiological sensor modules with applications in the medical industry. These modules are capable of measuring, processing, communicating one or more physiological parameters, and can be integrated into a wireless monitoring system. This paper describes the architecture of TELEMON, an embedded medical monitoring and alert system for patients with high medical risk. The system includes continuous monitoring of multiple vital signs, intelligent multiple parameter medical emergency detection, and an Internet/GSM connection to the monitoring centre.

Spectral analysis of fetal heart rate variability associated with fetal acidosis and base deficit values

The physiological response during fetal distress caused by labor varies from case to case and it is reflected both in the umbilical cord pH value and the fetal cord arterial base deficit (BDecf). The purpose of this study is to reveals the changes in fetal heart rate variability in abnormal cases (pH <; 7.2 and BDecf > 8 mmol/L). Fetal heart rate variability (fHRV) was computed in 289 records with both normal and abnormal fetal outcome. The records were divided into two groups, the control group and the test group. Next we computed the Fast Fourier Transform for each group to obtain the spectra for low, mid, and high frequency bands. We have used the normalized values of the mid and high frequency bands and the mid and high frequency ratio. We applied a t-test to divide the test group into two classes, and the pH and BDecf values were used to validate the results. Finally, we obtained a sensitivity of 96% and a specificity of 87.6%. The Spearman correlation coefficients and the scatter matrix also point to a very strong relationship between the fHRV metrics and the three outcome parameters: pH, BDecf, and Apgar scores.

Atrial fibrillation onset prediction using variability of ECG signals

This study presents the use of two different methods for the automatic prediction of the onset of paroxysmal atrial fibrillation (PAF) by means of surface electrocardiographic (ECG) signal. The first method is commonly used and consists in the analysis of the heart rate variability (HRV) of the ECG signal. Two significant parameters are taken into consideration: the time domain metric standard deviation of average five minute window of the time series (SDANN) and the frequency-domain metric low-frequency/high-frequency (LF/HF) ratio of the RR interval. The second analysis method, which is based on the morphological timing characteristics of the QRS complex, is called morphologic variability (MV) of the ECG signal, and was not used before for PAF prediction. Parameters similar to those of HRV analysis are determined in this case. Both methods are applied on 198 Holter records taken from the PAF Database from physionet.org portal. The results show a better accuracy of the MV analysis than that obtained by means of HRV technique alone. Moreover, by using an appropriate decision rule, both methods were “fused” and the overall accuracy of PAF onset prediction was raised up to 90%. Experimental results also indicate that our method is applicable for usual Holter recordings and is robust against noise and common artifacts. Its high prediction accuracy is comparable with that obtained by manual annotation made by experts and therefore is suitable to be used in clinical practice.

Parallel image registration using bio-inspired computing

In this paper it is proposed a parallel approach for the pixel intensity based image registration (IR) problem on multi-core processors. While IR is an optimization problem which computes the optimal parameters for a geometric transform, two classes of bio-inspired algorithms are studied: Bacterial Foraging Optimization Algorithm (BFOA) and Genetic Algorithm (GA). The optimal transform is applied to a source image in order to align it to a model image by maximizing a similarity measure. In the presented experiment, mutual information (MI) is used to evaluate the IR quality and most of the processing time is spent in this evaluation. The proposed parallel approach aims to reduce the processing time by using the full computing power of multi-core processors. A comparison of the sequential and parallel versions for different registration problems is presented.

TELEMON — A Complex System for Real Time Telemonitoring of Chronic Patients and Elderly People

This paper presents a project that has as main goal researches, design and implementation of an electronicinformatics- telecom and scalable system, that allows the automatic, complex and real time telemonitoring, everywhere and every time (at home, in hospitals, at work, etc.), using several communication paths, of (mobile) persons with chronic illnesses, of elderly people, of those having high medical risk and of those with neuro-locomotor disabilities. The monitored features are electrophysiological (vital) signs, signals for domotics (home surveillance, access control in a certain area), and the systems also performs automatic image analysis of the movements of the subjects.

Automatic multi-threshold image segmentation using metaheuristic algorithms

In this paper is presented an automatic segmentation approach for gray level images based on usage of metaheuristic swarming algorithms for multiple thresholds computing. The multi-threshold segmentation is an optimization problem while the thresholds must be determined and applied to the source image by minimizing an error measure. Because the number of possible solution may be very large in case of multiple thresholds, we used four metaheuristic swarming algorithms to obtain faster the optimal solution of the segmentation problem: Bacterial Foraging, Particle Swarming, Multi Swarm and Firefly optimization. As optimization criteria, root mean square error, peak signal-to-noise ratio and structural similarity index are used. Each optimization algorithm allows obtaining the optimal solution in a reasonable number of iterations and the obtained results were compared.

Image processing by means of some bio-inspired optimization algorithms

Image processing problems often require optimization algorithms to be applied. In this paper some aspects concerning the behavior of Bat and Cuckoo Search optimization algorithms are presented. The obtained accuracy and the processing time depend on the input images characteristics, chosen optimization criteria, dimension of the search space and, last but not least, on the chosen optimization algorithm and its parameters. The two nature inspired optimization algorithms were studied first in case of some mathematical functions minimization and then in case of bio-medical image registration.