Relationship between Task Difficulty and Probe Reaction Time in Postural Control

Abstract

[Purpose] The purpose of this study was to determine the relationship between postural sway and probe reaction time in single-leg standing with different task difficulties. [Subjects] Ten adults (six men and four women; mean age: 22.4 ± 1.0 years) were submitted to four dual-task conditions (double support standing, ground single-leg standing, and single-leg standing on three and five balance mats). [Methods] The probe reaction time was measured with auditory reaction task, and 2-dimensional accelerations that were assumed to be the index of the postural sway were also measured. [Results] The postural sway was smallest in double support standing, becoming larger in the order of ground single-leg standing, three balance mats, and five balance mats. The probe reaction time showed similar characteristics. [Conclusion] Similar to observations in the previous studies, it was confirmed that probe reaction time increased as postural sway increased.