On the use of approximate entropy and sample entropy with centre of pressure time-series

• Published in: Journal of neuroengineering and rehabilitation 2018-12, Vol.15 (1), p.116-116, Article 116
• Main Authors: Montesinos, Luis, Castaldo, Rossana, Pecchia, Leandro
• Format: Article
• Language: English
• Subjects: Adult; Adults; Aged; Algorithms; Approximate entropy; Balance; Centre of pressure; Computer Simulation; Entropy; Entropy (Thermodynamics); Falls; Female; Human balance; Humans; Male; Mathematical analysis; Middle Aged; Models, Biological; Older people; Parameter sensitivity; Physiology; Postural Balance - physiology; Postural control; Posture; Posturography; Pressure; Sample entropy; Senses; Time series; Time series analysis; Variance analysis; Young Adult; Young adults
• ISSN: 1743-0003; 1743-0003
• DOI: 10.1186/s12984-018-0465-9

Approximate entropy (ApEn) and sample entropy (SampEn) have been previously used to quantify the regularity in centre of pressure (COP) time-series in different experimental groups and/or conditions. ApEn and SampEn are very sensitive to their input parameters: m (subseries length), r (tolerance) and N (data length). Yet, the effects of changing those parameters have been scarcely investigated in the analysis of COP time-series. This study aimed to investigate the effects of changing parameters m, r and N on ApEn and SampEn values in COP time-series, as well as the ability of these entropy measures to discriminate between groups. A public dataset of COP time-series was used. ApEn and SampEn were calculated for m = {2, 3, 4, 5}, r = {0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5} and N = {600, 1200} (30 and 60 s, respectively). Subjects were stratified in young adults (age