Influence of a Temporary Mental Stress Task on the Center of Pressure

Abstract

This study aimed to examine the influence of a temporary mental stress load on center of pressure (COP) sway with time. We selected the Uchida-Kraepelin psychological (UKP) test as a mental load task (mental calculation task condition), and an easy questionnaire with little mental load as a placebo task (placebo task condition). Ten healthy young male students were measured for heart rate (HR), blood pressure (BP), subjective mental burden against the tasks, and COP sway before (Pre-test), just after (Post-test 1), 5 min (Post-test 2), 10 min (Post-test 3), and 15 min after (Post-test 4) both tasks. There was no significant change in HR and BP in the mental calculation task condition. A mental burden was significantly higher in Post-test 1 than in the Pre-test, Post-tests 3 and 4, and in the Post-test 1, it was significantly higher in the mental calculation task condition. Three COP sway parameters of mean path length, root mean square of velocity, and vector of E direction velocity showed significant differences and in Post-test 1 were higher in the mental calculation task condition, and tended to be higher in Post-test 1 than the other tests, but recovered to a baseline level at 10 min after the tasks. In healthy young adults, an excessive mental burden may temporarily affect COP sway velocity. It is suggested that considering a subject's temporal mental stress as an effect factor is important in an equilibrium test in the clinical settings.