Richman, J., and Moorman, J. (2000) Physiological time-series analysis using approximate entropy and sample entropy. American Journal of Physiology—Heart and Circulatory Physiology, 278, H2039-H2049.

has been cited by the following article:

• TITLE: About the structure of posturography: Sampling duration, parametrization, focus of attention (part I)

  AUTHORS: Patric Schubert, Marietta Kirchner, Dietmar Schmidtbleicher, Christian T. Haas

  KEYWORDS: Center of Pressure; Sample Duration; Posturographic Parameters; Exploratory Factor Analysis; Nonlinear Methods; Internal Focus of Attention

  JOURNAL NAME: Journal of Biomedical Science and Engineering, Vol.5 No.9, September 19, 2012

  ABSTRACT: This study investigates the choice of posturographic parameter sets with respect to the influence of different sampling durations (30 s, 60 s, 300 s). Center of pressure (COP) data are derived from 16 healthy subjects standing quietly on a force plate. They were advised to focus on the postural control process ( i.e. internal focus of attention). 33 common linear and 10 nonlinear parameters are calculated and grouped into five classes. Component structure in each group is obtained via exploratory factor analysis. We demonstrate that COP evaluation—irrespective of sampling duration—necessitates a set of diverse parameters to explain more variance of the data. Further more, parameter sets are uniformly invariant towards sampling durations and display a consistent factor loading pattern. These findings pose a structure for COP parametrization. Hence, specific recommendations are preserved in order to avoid redundancy or misleading basis for inter-study comparisons. The choice of 11 parameters from the groups is recommended as a framework for future research in posturography.