| Abstrakt: |
The aim of the work was to assess the stability (intraindividual variability) of two integral parameters of the human EEG, which characterize its spatial and temporal order in a resting state with the eyes closed or open or while performing several types of tasks. A longitudinal dynamic study of the parameters in a healthy male subject was carried out for 1.5 years. The subject was in a calm waking state with his eyes closed for at least 2 min at the beginning and end of each session and between tests in a session. A session included six auto-training tasks lasting at least 12 min, a calculation test (consecutive subtraction of a given two-digit number from a given four-digit number), a verbal test (mental selection of nouns that start with a given letter relatively rare occurring as the first letter in Russian words (ф, ц, ч, х, etc.)), and gaze fixation at a given point in a resting state with the eyes open. A parameter estimation algorithm utilized the first-order multivariate structural function. A scatterplot of parameter values was found to have a distinct elliptic structure. Its geometric characteristics (the center of the ellipse, its orientation, and the lengths of the main axes) changed between registrations and between states, indicating that each sample of integral EEG parameters did not fully represent the population. This feature is inherent in the phenomenon under study and should be taken into account when comparing the EEG analysis results obtained at different time points even from the same subject. [ABSTRACT FROM AUTHOR] |
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