The main goal of my work is to replicate the results obtained from an experimental setup. In this experiment, individuals from three different categories, namely healthy subjects (HS), subjective cognitive decline (SCD), and mild cognitive impairment (MCI), were asked to perform a visual attention task. Here different geometrical figures were displayed and the corresponding electrophysiological response to the stimulus, event-related potentials (ERPs), were recorded. The analysis of EEG data, coming from channels in correspondence of the visual cortex, revealed alterations in visual evoked potentials (VEPs) which correspond to the first physiological response to the stimulus and that are nonlinear with the worsening of the cases considered.