A Comparison of Postural Stability during Upright Standing between Normal and Flatfooted Individuals, Based on COP-Based Measures

Abstract

Aging causes foot arches to collapse, possibly leading to foot deformities and falls. This paper proposes a set of measures involving an entropy-based method used for two groups of young adults with dissimilar foot arches to explore and quantize postural stability on a force plate in an upright position. Fifty-four healthy young adults aged 18-30 years participated in this study. These were categorized into two groups: normal (37 participants) and flatfooted (17 participants). We collected the center of pressure (COP) displacement trajectories of participants during upright standing, on a force plate, in a static position, with eyes open (EO), or eyes closed (EC). These nonstationary time-series signals were quantized using entropy-based measures and traditional measures used to assess postural stability, and the results obtained from these measures were compared. The appropriate combinations of entropy-based measures revealed that, with respect to postural stability, the two groups differed significantly (p < 0.05) under both EO and EC conditions. The traditional commonly-used COP-based measures only revealed differences under EO conditions. Entropy-based measures are thus suitable for examining differences in postural stability for flatfooted people, and may be used by clinicians after further refinement.

Feet deformities and their close association with postural stability deficits in children aged 10–15 years

“…Also Cote et al [27] reported that the actual structure of the foot affected overall postural stability, be that in static or dynamic conditions. Tahmasebi et al [28], and Chao et al [29], when comparing a group of the flat footed patients with the ones with the correctly arched feet, observed that there was an appreciable deterioration of overall postural stability in the flat footed subjects.…”

Applied COP-Based MMSE Method and Modular Interactive Tiles on Postural Stability Enhance in Patients with Chronic Stroke: A Pilot Study

“…Chen and Jiang applied the MSE and MMSE approaches to analyze the gait function of 24 elderly, chronically ill patients with cardiovascular disease, diabetes mellitus, or osteoporosis [33]. Chao and Jiang based on COP-Based MMSE measures, further analysis to make a comparison of postural stability during upright standing between normal and flatfooted Individuals of 54 healthy young adults [34]. Their results showed that the MSE algorithms used to identify the sense of balance in young adults and elderly individuals were inferior to the MMSE algorithms utilized for the calculation of the CI of COP data.…”

Empirical Mode Decomposition-Derived Entropy Features Are Beneficial to Distinguish Elderly People with a Falling History on a Force Plate Signal

“…In a study by Ahmadi et al, sample entropy (as an indicator of COP) was higher in participants who were walking while playing games than in participants who were only walking [ 16 ]. Chao et al used two nonlinear parameters, namely sample entropy and multivariate sample entropy, to compare the COP of individuals with regular feet and flat feet [ 17 ].…”

“…The data investigated in this article are from an open database developed by Santos et al [ 16 ]. Montesinos et al analyzed the same dataset and explored the various default parameters of approximate entropy and sample entropy relevant to these features [ 17 ]. However, there are few entropy features that are statistically significant between fall and non-fall groups of elderly subjects.…”