Applications of medical intelligence in remote monitoring.

Prevention and rehabilitation efficiency can greatly benefit from the application of intelligent, 24 hour tele-diagnostics and tele-care information systems. Tele-monitoring also supports a new level of medical supervision over the patient's lifestyle. In this paper we briefly present the architecture and development phase results of the Alpha remote monitoring system. The novelty of the system is the unified and flexible processing of various signals retrieved from modern, unobtrusive devices in an efficient signal abstraction framework. The signals include PIR motion sensors that record patient movement in the home, physiological signals and also patient responses in various tests performed on the GUI of the central home unit. We have developed and tested the prototype system with promising results.

Beat-to-beat interplay of heart rate, ventricular depolarization, and repolarization.

To improve malignant arrhythmia risk stratification, the causal and random components of spatiotemporal dynamics of heart rate (RR distances), ventricular depolarization sequence, and repolarization disparity were studied based on body surface potential map records taken for 5 minutes, in resting, supine position on 14 healthy subjects (age range, 20-65 years) and on 6 arrhythmia patients (age range, 59-70 years). Beat-to-beat QRS and QRST integral maps, Karhunen-Loève (KL) coefficients, RR, and nondipolarity index time series were computed. Tight relationship was found between RR and QRS integrals in healthy subjects with less association in arrhythmia patients. Tight KL-domain multiple linear association (r(2) > 0.72) was found between the QRS and QRST integral dynamics (ie, depolarization sequence and repolarization disparity). Beat-to-beat probability of the generation of significant nondipolarity index spikes was proportional to the QRST KL-component standard deviations (SD(i)) and inversely proportional with the mean dipolar KL components (M(i)) of the average QRST integral map.

Evaluation of the brain network organization from EEG signals: a preliminary evidence in stroke patient.

Synchronous brain activity in motor cortex in perception or in complex cognitive processing has been the subject of several studies. The advanced analysis of cerebral electro-physiological activity during the course of planning (PRE) or execution of movement (EXE) in a high temporal resolution could reveal interesting information about the brain functional organization in patients following stroke damage. High-power (128 channels) electroencephalography registration was carried out on 8 healthy subjects and on a patient with stroke with capsular lacuna in the right hemisphere. For activation of motor cortex, the finger tapping paradigm was used. In this preliminary study, we tested a theoretical graph approach to characterize the task-related spectral coherence. All of the obtained brain functional networks were analyzed by the connectivity degree, the degree distribution, and efficiency parameters in the Theta, Alpha, Beta, and Gamma bands during the PRE and EXE intervals. All the brain networks were found to hold a regular and ordered topology. However, significant differences (P < 0.01) emerged between the patient with stroke and the control subjects, independently of the neural processes related to the PRE or EXE periods. In the Beta (13-29 Hz) and Gamma (30-40 Hz) bands, the significant (P < 0.01) decrease in global- and local-efficiency in the patient's networks, reflected a lower capacity to integrate communication between distant brain regions and a lower tendency to be modular. This weak organization is principally due to the significant (P < 0.01 Bonferroni corrected) increase in disconnected nodes together with the significant increase in the links in some other crucial vertices.

Importance of body surface potential field representation fidelity: analysis of beat-to-beat repolarization measurements.

OBJECTIVE: According to previous studies, the complex substrate of malignant arrhythmias needs a detailed spatio-temporal noninvasive characterization of low-amplitude dynamic changes in beat-to-beat cardiac repolarization. METHODS: Body surface potential map (BSPM) records were taken on 14 healthy male and female subjects (age 20-80 years) and on 6 ventricular arrhythmia patients, 4 of them with implanted cardioverter defibrillators (ICD). Records were taken continuously, for 5 minutes, in resting, supine position. Beat-to-beat QRST integral maps, Karhunen-Loéve coefficient time-series (KLi, i=1-12), RR and nondipolarity index (NDI) time-series were computed. RESULTS: The first order statistical properties of the spatio-temporal variability of subsequent QRST integral maps were characterized by the box and whiskers plot of their KLi components. The SD2/M2 (KLi amplitude variance/mean signal energy) values of the QRST integral maps in the normal group ranged between 0.0057 and 0.008 (i.e. 0.075=or

Novel neuroradiological image processing and information retrieval in a telestroke system.

A Cellular Neural Network based image processing system and a system based on Interaction Information Retrieval which are basic elements of a stroke teleconsultation system with most recent applications are introduced in this paper. Both of them are novel approaches in the image processing and information retrieval fields.

The use of the SPSA method in ECG analysis.

The classification, monitoring, and compression of electrocardiogram (ECG) signals recorded of a single patient over a relatively long period of time is considered. The particular application we have in mind is high-resolution ECG analysis, such as late potential analysis, morphology changes in QRS during arrythmias, T-wave alternants, or the study of drug effects on ventricular activation. We propose to apply a modification of a classical method of cluster analysis or vector quantization. The novelty of our approach is that we use a new distortion measure to quantify the distance of two ECG cycles, and the class-distortion measure is defined using a min-max criterion. The new class-distortion-measure is much more sensitive to outliers than the usual distortion measures using average-distance. The price of this practical advantage is that computational complexity is significantly increased. The resulting nonsmooth optimization problem is solved by an adapted version of the simultaneous perturbation stochastic approximation (SPSA) method of. The main idea is to generate a smooth approximation by a randomization procedure. The viability of the method is demonstrated on both simulated and real data. An experimental comparison with the widely used correlation method is given on real data.

Extraction of intrinsic timing features of cardiac activation from body surface potential maps.

According to previous modeling studies--propagation of depolarizing wave fronts--consists of subintervals, each characterized by a smooth progression of waves through the myocardium. At the onset and end of these intervals, abrupt changes occur in the 3D pattern of activation waves (e.g. at the time of the collision of activation waves with other waves, obstacles or unexcitable myocardium and epicardial breakthrough), which manifest themselves in the surface ECG as "jumps" (high frequency notches and slurs). The timing of jumps provides diagnostic information on bioelectrical tissue properties of the heart. Findings of this study validated previous simulation results. Furthermore, essential signal processing requirements were formulated for a high-resolution body surface potential mapping technology.

Computer aided interactive remote diagnosis of Parkinsonians.

We develop a diagnostic tool to support the objective diagnosis of Parkinsonians. We suggest a cost and time efficient diagnostic tool: patients may complete exercises using a personal computer at home and the data is gathered for further studies via Internet in a central database.

Methodological studies related to cardiovascular risk assessment.

Based on Framingham risk estimating equations by computer simulation graphical tools were gained allowing reasonable decision threshold adjustments in cardiovascular screening procedures. Results quantitatively characterize the percentage of the population selected for detailed evaluation vs. the decision threshold in a hypothetical screening procedure. In the second part of the study, the effect of blood pressure (BP) measurement uncertainties on coronary heart disease incidence estimates was characterized. According to our results the use of daily BP averages instead of instantaneous measurements has a significant impact on the risk estimation reliability.