Comparison of mathematical models of planar and ellipsoid media, taking into account the influence of physiological parameters of head tissues on the amplitude of visual evoked potentials

Authors: Shimchenko L.A., Osintseva E.D.
Published in issue: #3(44)/2020
DOI: 10.18698/2541-8009-2020-3-591
Category: Medical sciences | Chapter: Medical equipment and devices
Keywords: visual evoked potentials, multiple sclerosis, cerebrospinal fluid, skull, scalp, current dipole, amplitude, mathematical model
Published: 06.04.2020

Modeling the influence of parameters of human head tissues (scalp, skull, cerebrospinal fluid) on the amplitudes of visual evoked potentials recorded from the surface of the scalp. The purpose of this work was to compare two mathematical models for different environments: planar and ellipsoidal. When comparing models, a mathematical model in an ellipsoidal environment showed a more accurate value of the amplitude, since it takes into account the geometric curvature of the head. The average relative error of the planar model is 65%. The average relative error of the effect of the thickness of the cerebrospinal fluid (CSF) layer and the dipole depth on the amplitude was 13% for the ellipsoid model, and 15% for the planar; the effect of skull thickness on amplitude for the ellipsoid model was less than 1%, and for the planar model it was about 3%. Based on this, it can be concluded that a change in the thickness of the CSF layer has a significant effect on the amplitude of the recorded signal, however, when varying the thickness of the skull, the effect will be minimal, i.e., an increase in the dipole depth is equivalent to an increase in skull thickness by 1 mm.

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