Multi-stimulus multi-response posturography

In this study a method for the analysis of simultaneous multiple measuremen ts of kinematics and stabilizing forces related to human postural dynamics is proposed. Each subject in a group of normal subjects (n = 10) was tested with eyes-open and eyes-closed with simultaneous but uncorrelated vestibul ar and proprioceptive stimuli in order to investigate the contributions of individual sensory feedback loops. Statistical analysis was made by means o f multi-input multi-output identification of a transfer function from stimu li to stabilizing forces of the feet and the resulting body position, the t ransfer function being compatible with a biomechanical model formulated as a stabilized segmented inverted pendulum subject to feedback of body sway a nd position. Each individual model estimated is effective in predicting a s ubject's response to new stimuli and in describing the interacting effects of stimuli on body kinetics. The proposed methodology responds to the curre nt needs of data analysis of multi-stimulus multi-response experiments. (C) 2001 Published by Elsevier Science Inc.