The Effects of Delayed Visual Feedback on Postural Dynamics

Abstract

We report on experiments and modeling of the interactions between delayed visual feedback and postural control in human quiet stance. A heuristic model is derived based on physiological and psychophysical parameters. The level of agreement found between the data and the model was found to be very good for power spectral densities, probability density functions and mean-squared displacements (or Hurst exponents). The stochastic delayed differential model identifies critical time scales of postural corrections. We also investigate properties of the model such as stability, small delay approximations and the power spectral density. Lastly, we use nonlinear time series techniques to investigate the temporal structure of the experimental postural dynamics. We propose the first dynamical model of visually assisted posture control.