Thursday, April 24, 1997, 4:00 p.m.

J.J. Collins
Boston University, Department of Biomedical Engineering

Random Walking During Quiet Standing

The task of maintaining erect stance involves a complex sensorimotor control system, the output of which cab be highly irregular. Even when a healthy individual attempts to stand still, the center of gravity of his or her body and the center of pressure (COP) under his or her feet continually move about in an erratic fashion. In this paper, we describe a new technique, known as stabilogram-diffusion analysis, for analyzing quiet-standing posture data. With this approach, COP trajectories are analyzed as one-dimensional and two dimensional random walks. We describe how the stabilogram-diffusion analysis leads to the extraction of repeatable COP parameters which can be directly related to the steady-state behavior and functional interaction of the neuromuscular mechanisms underlying the maintenance of erect stance. We also discuss how we have used this technique to gain insight into: (a) the effects of visual input on postural control mechanisms and (b) age related changes in postural control mechanisms.