A.A. Slezkin1, N.G. Gusein-zade2

1 Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences (Moscow, Russia)

1 The Institute of Radio Electronics and Informatics of the Russian Technological University (Moscow, Russia)

2 Prokhorov General Physics Institute of the Russian Academy of Sciences (Moscow, Russia)

In this paper, we study the effect of inaccuracy in determining the onset of electroencephalographic stimuli on the shape and location of evoked potential (EP) peaks.

EP is a signal generated by neural ensembles that are activated when an external stimulus is applied or some endogenous event occurs. The EP value recorded on the head surface is too small compared to the EEG background activity that is not synchronous with the stimulus, which significantly complicates the possibility of their registration and study. To solve this problem, the method of synchronous accumulation is used, which has become widespread due to the development of computer technology. However, when calculating evoked potentials of any modality, due to inaccuracies in determining the beginning of each stimulus on the time axis, errors occur in determining the shape of the EP. A random shift of signals or their individual components (peaks) along the time axis leads to an increase in the width of the components and a decrease in their amplitude, and in the limiting case, to the impossibility of separating signals and misclassifying the components.

In the general case, the greater the variability of the time of the start of signal processing during the coherent synchronous accumulation procedure, the slower the signal-to-noise ratio increases, as a result of which, in order to obtain a reliable signal estimate, an increase in the number of recorded responses to stimuli is required.

In this work, we evaluated the maximum allowable error in determining the beginning of the stimulus, which allows you to correctly assess the parameters of the EP and, accordingly, correctly perform clinical diagnostics. Consideration is carried out on the example of auditory (acoustic) stimuli.

Slezkin A.A., Gusein-zade N.G. Evaluation of the influence of inaccuracy in determining the onset of electroencephalographic stimuli on the shape of evoked potentials. Biomedicine Radioengineering. 2023. V. 26. № 4. P. 59–65. DOI: https://doi.org/10.18127/ j15604136-202302-06 (In Russian)

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