Analysis on postural stabilization from visual feedback through Brownian motion modeling / 医用生物力学

ABSTRACT

Objective To explore postural stabilization of visual feedback to human body and its mechanisms. Methods Displacement of the center of pressure (COP) of 12 healthy young adult volunteers were investigated under upright posture with and without visual feedback conditions. The Brownian motion model was employed to compare the differences in diffusion coefficients, Hurst exponents, and critical points of the COP trajectories under the above two conditions, and one way repeated measures ANOVA was utilized to test the significance of these differences. ResultsUnder the visual feedback condition, in long-term time intervals, diffusion coefficients were reduced by about two thirds and Hurst exponents reduced by half; in short-term time intervals, no significant differences were found in diffusion coefficients in the medial-lateral (ML) direction and in Hurst exponents; in addition, the coordinates of the critical points presented no statistically significant differences in the time intervals except for the mean square displacement in the anterior posterior (AP) direction. ConclusionsVisual feedback enhances the closed-loop control mechanism of postural control, while it does not have great impact on the open-loop control mechanism and transitional characteristics of the two mechanisms; moreover, the effect of visual feedback on postural control in AP direction is more obvious than that in ML direction.