Previous research has shown that changes in the spectral power of the alpha, beta and theta rhythms can be a good indicator of the load caused by performing different types of cognitive and psychomotor tasks. In this study, neural activity was recorded while performing the Fitts’ Tapping Tasks, a kind of psychomotor tasks. These tasks were used since their difficulty is objectively quantified and expressed in bits. The tasks used had difficulty levels of 2, 4 and 6 bits. The aim of the study was to determine how sensitive the changes in the power spectrum of the three frequency bands is in relation to changes in task difficulty. 35 participants between the ages of 19 and 22 took part in the study. All participants were righthanded and had no neurological diagnoses. During the performance of the tasks, the EEG was recorded, as well as electrooculography (EOG). The EEG was also recorded during the resting phase, in which the subjects sat with their eyes open. The electrodes for EEG recording were placed at the following positions: F3, F4, FC3, FC4, C3, C4, CP3, CP4, P3, P4, Fz, FC, Cz. The results showed that all three frequency ranges (α, β and θ) were able to distinguish periods of task performance from periods of rest, since spectral powers were different for different conditions. Changes in the alpha power were found in the parietal area, while changes in the beta and theta rhythms were dispersed. A change in task difficulty led to changes in the power of the beta rhythm, but not of the alpha and theta rhythms. With increasing task difficulty, the power of the beta rhythm increased in all used electrode positions, but these changes are not linear, as there is a difference when comparisons are made for tasks of 2 and 6 bits, and 4 and 6 bits, but not for 2 and 4 bits. These changes were interpreted as a consequence of an increase in cognitive load.

EEG, alpha, beta, theta, Fitts’ Tapping Tasks