Corrigendum: Frequency-Specific Fractal Analysis of Postural Control Accounts for Control Strategies
- 1CATIE - Centre Aquitain des Technologies de l'Information et Electroniques, Talence, France
- 2Univ. Bordeaux, CNRS, Laboratoire IMS, UMR 5218, Talence, France
by Gilfriche, P., Deschodt-Arsac, V., Blons, E., and Arsac, L. M. (2018) Front. Physiol. 9:293. doi: 10.3389/fphys.2018.00293
In the original article, there was an error. In the Discussion, we analyze how the scaling exponents computed on the differentiated signal and the original signal can be used to describe the frequency content of the signal in a global model. When differentiating the signal, we supposed that the value of β increased by 2, however, as β is the opposite of the slope in the power spectral density, the value of β decreased by 2 when the signal is differentiated. Thus, the equations β1 = 2 × α1 +1 and β1 = (2 × α1 − 1)+2 are incorrect and should be replaced by: β1 = 2 × α1 − 3 and β1 = (2 × α1−1)−2.
A correction has been made to Discussion, Interpretations and confrontation with other theories, paragraph two:
Indeed, Figure 7 shows that the whole frequency content of the CoP velocity signal could then be described by four parameters:
• Pf0 (or AAMV)
• β1, the opposite of the slope of the low-frequency antipersistent range, with
• α1 being here the frequency-specific fractal exponent associated with visuo-vestibular loops (low-frequencies) in CoP position. This result is obtained by the fact that β1 is computed from the CoP velocity while α1 is computed from CoP position, its integral, so more precisely: β1 = (2 × α1 − 1) − 2.
• β2, the opposite of the slope of the high-frequency persistent range, with
• α2 being here the frequency-specific fractal exponent associated with proprioceptive loops (high-frequencies) in CoP velocity.
• f0, the crossover frequency, which might be variable from one individual to another but is likely between 0.5 and 2 Hz according to the literature.
The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.
Conflict of interest statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Keywords: postural control, center-of-pressure, fractal physiology, DFA, FsFA, 1/f scaling
Citation: Gilfriche P, Deschodt-Arsac V, Blons E and Arsac LM (2018) Corrigendum: Frequency-Specific Fractal Analysis of Postural Control Accounts for Control Strategies. Front. Physiol. 9:1566. doi: 10.3389/fphys.2018.01566
Received: 14 August 2018; Accepted: 18 October 2018;
Published: 02 November 2018.
Edited and reviewed by: Zbigniew R. Struzik, The University of Tokyo, Japan
Copyright © 2018 Gilfriche, Deschodt-Arsac, Blons and Arsac. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Pierre Gilfriche, firstname.lastname@example.org