Parameter Reduction in the Frequency Analysis of Center of Pressure in Stabilometry

Abstract

During postural stability evaluation frequency analyses are applied on the motion of the foot center of pressure (CoP). In this study we compared the most widely used frequency type CoP parameters (median frequency, mean power frequency, bandwidth) including some newly defined parameters (frequency range power ratios, spectral power ratio between the anteroposterior and mediolateral directions, largest CoP amplitude with the corresponding frequency). The parameters were acquired from 25 young and healthy participants. Correlation analysis was used to exclude parameters that contain redundant information. Variance analysis was used to evaluate the behavior and usability of the parameters in different stance conditions (bipedal stance with eyes open and eyes closed, single leg stance with eyes open) where the balancing capability alters. Based on our results we recommend using the largest amplitude and frequency power ratios between specified frequency bands, spectral power ratio between anteroposterior and mediolateral direction and mean power frequency.