Next Article in Journal
Confidence Interval Estimation for Precipitation Quantiles Based on Principle of Maximum Entropy
Previous Article in Journal
A New Phylogenetic Inference Based on Genetic Attribute Reduction for Morphological Data
Previous Article in Special Issue
An Improved Method of Handling Missing Values in the Analysis of Sample Entropy for Continuous Monitoring of Physiological Signals
Article Menu
Issue 3 (March) cover image

Export Article

Open AccessArticle
Entropy 2019, 21(3), 314;

Development of Postural Stability Index to Distinguish Different Stability States

Department of Industrial Management, National Taiwan University of Science and Technology, 43 Keelung Road Section 4, Daan District, Taipei City 10607, Taiwan
Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
Author to whom correspondence should be addressed.
Received: 22 February 2019 / Revised: 14 March 2019 / Accepted: 20 March 2019 / Published: 22 March 2019
(This article belongs to the Special Issue Multiscale Entropy Approaches and Their Applications)
PDF [575 KB, uploaded 22 March 2019]


A key factor for fall prevention involves understanding the pathophysiology of stability. This study proposes the postural stability index (PSI), which is a novel measure to quantify different stability states on healthy subjects. The results of the x-, y-, and z-axes of the acceleration signals were analyzed from 10 healthy young adults and 10 healthy older adults under three conditions as follows: Normal walking, walking with obstacles, and fall-like motions. The ensemble empirical mode decomposition (EEMD) was used to reconstruct the acceleration signal data. Wearable accelerometers were located on the ankles and knees of the subjects. The PSI indicated a decreasing trend of its values from normal walking to the fall-like motions. Free-walking data were used to determine the stability based on the PSI. The segmented free-walking data indicated changes in the stability states that suggested that the PSI is potentially helpful in quantifying gait stability. View Full-Text
Keywords: postural stability index; stability states; ensemble empirical mode decomposition; gait postural stability index; stability states; ensemble empirical mode decomposition; gait

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Nurwulan, N.R.; Jiang, B.C.; Novak, V. Development of Postural Stability Index to Distinguish Different Stability States. Entropy 2019, 21, 314.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Entropy EISSN 1099-4300 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top