Shape Analysis of Postural Sway Area

Measurement of the human body centre of pressure (COP) movement (postural sway) with a force platform is a standard procedure for the assessment of postural stability. Recently we proposed a method where the outline of the sway region is expressed in terms of Fourier coefficients determined by asymmetric fitting and minimal outline bending. The index of sudden excursions (ISE) is defined as the ratio of this sway area to the one obtained by the standard principal component analysis. The meaning and the discriminative power of this index is still an open question, which is addressed in present work.