Effect of object position on evoked potentials during long-term cognitive tests

This article examines the effect of object position on cognitive evoked potentials observed in subjects with chronic pain. Chronic pain often causes cognitive depression. The experiment consisted of passing small cognitive tests, where the subject assessed the number of squares presented on the left or right side of the screen, or in the center. A simple method is proposed for automatic identification of the main components of the cognitive evoked potential, based on the identification of extrema and the assessment of the amplitudes of the main components of the cognitive evoked potential. Examples of analysis of individual characteristics for several subjects are shown. The maximum difference between the adjacent main components of the evoked potential lies, as a rule, on the central axis, but can be located in the subjects in the frontal, parietal, or occipital lobes. For two subjects, the individual characteristics of the main components of the cognitive evoked potential were shown at different positions of the object on the screen during the performance of the cognitive test. For one, the evoked potentials change when the stimulus is located on the left side of the screen. For the second, large changes are observed when the stimulus is located on the right side of the screen. It is extremely important to know these characteristics of the subjects when setting up automated brain-computer interfaces.