TREDEX - new name of "DX-systems" company. Equipment for telemedicine, EEG, ECG.


Publications
EXPERIENCE OF ECG RADIO MONITORING IN MULTIFIELD HOSPITAL

I.A. Tolkacheva

Analysis of long-term ECG monitoring through a radio channel in the Kharkov Central clinical hospital No. 5. Organizational aspects of implementation of novel information technologies in diagnostic investigations. High efficiency of ECG radio monitoring of patients is demonstrated basing on real clinical cases.


published 02.12.2003


R.V.Pavlovich

 


(128 KB)
published 09.12.2003


A.V.Kramarenko

The article is a brief summary of the fundamental principles of EEG system design. It is based on almost twenty-year experience in the creation of systems of functional diagnostics and contains strict and clear interpretation of the main technical terms, which characterize the quality of electroencephalographic systems. Although the article requires special knowledge from the reader, it is of interest for professionals in the field of electroencephalography, as well as for system engineers, who independently develop a system of functional diagnostics. Taking into account that many terms used in the article require explanations, the article is completed with a simplified glossary. Harshness of some definitions of the author is an inevitable reaction to the real state of the matter with electroencephalographic equipment in Ukraine.


(1 578 KB)
published 09.12.2003


A.V.Kramarenko

 


(748 KB)
published 09.12.2003


A.B.Kramarenko, R.V.Pavlovich, L.V.Pavlyutin

 


(298 KB)
published 09.12.2003


A.B. Kramarenko, Uner Tan

Cell phones emitting pulsed high-frequency electromagnetic fields (EMF) may affect the human brain, but there are inconsistent results concerning their effects on electroencephalogram (EEG). We used a 16-channel telemetric electroencephalograph (ExpertTMR), to record EEG changes during exposure of human skull to EME emitted by a mobile phone. Spatial distribution of EME was especially conce ntrated around the ipsilateral eye adjacent to the basal surface of the brain. Traditional EEG was full of noises during operation of a cellular phone. Using a telemetric electroencephalograph (ExpertTMR) in awake subjects, all the noise was eliminated, and EEG showed interesting changes: after a period of 10-15 s there was no visible change, the spectrum median frequency increased in areas close to antenna; after 20-40 s, a slowwave activity (2.5-6.0 Hz) appeared in the contralateral frontal and temporal areas. These slow waves lasting for about one second repeated every 15--20 s at the same recording electrodes. After turning off the mobile phone, slow-wave activity progressively disappeared; local changes such as increased median frequency decreased and disappeared after 15-20 min. We observed similar changes in children, but the slow-waves with higher amplitude appeared earlier in children (10-20 s) than adults, and their frequency was lower (1.0-2.5 Hz) with longer duration and shorter intervals. The results suggested that cellular phones may reversibly influence the human brain, inducing abnormal slow waves in EEG of awake persons.

(2 537 KB)
published 09.12.2003

VALIDITY OF SPECTRAL ANALYSIS OF EVOKED POTENTIALS IN BRAIN RESEARCH

A.B. Kramarenko, Uner Tan

The averaged electronencephologram (EEG) response of the brain to an external stimulus (evoked potential, EP) is usually subjected to spectral analysis using the fast Fourier transform (FFT), especially to discover the relation of cognitive ability to so-called brain dynamics. There is indeed a discrepancy between these two systems, because the brain is a highly complex nonlinear system, analyzed by a linear system (FFT). We present in this work some inaccuracies that occurred when EPs are subjected to spectral analysis, using a model signal. First of all, the EP power spectra depended upon the number of samples used for averaging; the input EP (model signal) and the output EP (from the system) seemed to be similar in forms, but they exhibited completely different spectral power curves. It was concluded that the spectral analysis of evoked responses by using FFT (linear system analysis) in relation to brain (highly complex nonlinear system) may mislead neuroscientists.

published 09.12.2003


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