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Nonlinear changes in cardiovascular and psychomotor systems while performing Fitts tapping tasks

Previous studies have shown that physiological systems have linear and nonlinear characteristics of temporal changes. However, there are few studies that examined the nonlinear dynamic of the psychophysiological systems under the influence of workload, and even less frequent are those which have followed parallel changes in several different systems. Therefore, the aim of this research was to check whether the changes in the workload cause the same/similar changes in two psychophysiological systems, psychomotor and cardiovascular. The study included 40 participants, who performed psychomotor Fitts tapping tasks (2, 4, 6 bits). These tasks were chosen due to the fact that their workloads can be precisely expressed quantitatively. An electronic version of Fitts tapping tasks was used which allowed recording of intertap intervals. While performing the tasks cardiovascular activity was also recorded. Values of Lyapunov exponents for three workload levels within both systems were positive which implies that they were chaotic. When it comes to the complexity of the systems (correlation dimension) it can be said that the psychomotor system was more complex than cardiovascular. Psychomotor system complexity was reduced with workload increase. The same trend was obtained for cardiovascular system, but the differences were not significant. Index of determinism was equal for two systems. This parameter was stable for psychomotor system through different workloads but not for the cardiovascular system. Generally, it can be said that the workload level affected changes in the nonlinear dynamics of the cardiovascular and psychomotor system in different manners.

Nonlinear dynamics, psychomotor system, cardiovascular system, task load

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