Document Detail


Multifractal analysis of laser Doppler flowmetry signals before and after arm-cranking exercise in an older healthy population.
MedLine Citation:
PMID:  23387723     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Purpose: There is a lot of speculation about the role of nitric-oxide (NO) in the improvement usually noticed in microcirculatory function, following exercise. The knowledge of the underlying mechanisms leading to such an improvement is important as it may help in targeting and implementing therapies for microcirculatory diseases. Through a laser Doppler flowmetry (LDF) signal processing study, the authors' goal is to compare multifractal spectra of LDF data recorded in both lower leg and forearm, during different exercise conditions, in an older, untrained but healthy population.Methods: Using the method suggested by Halsey et al. [Phys. Rev. A 33, 1141-1151 (1986)], multifractal spectra of LDF signals recorded on lower leg and forearm before and after exercise (arm-cranking), before and after acetylcholine (ACh) iontophoresis, were determined on scales in relation with the NO-dependent endothelial activity. The width of each multifractal spectrum was then computed through the maximum and minimum Hölder exponent values for which the multifractal spectrum reaches its minimal values. The results were then compared.Results: Following exercise and on the scales studied, the average width of the multifractal spectra in both lower leg and forearm does not vary significantly before and after ACh iontophoresis. Similarly, following ACh iontophoresis and exercise, the average width of multifractal spectra remains statistically unchanged, when compared to that measured prior to exercise, in both upper and lower body, although negative trends can be observed.Conclusions: For the authors' population and for the type of exercise that the authors have chosen, the authors showed that the width of the multifractal spectra of LDF signals does not change significantly on scales in relation with the NO-dependent endothelial activity. Future studies may involve comparisons with signals obtained in patient populations.
Authors:
Markos Klonizakis; Anne Humeau-Heurtier
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Medical physics     Volume:  40     ISSN:  0094-2405     ISO Abbreviation:  Med Phys     Publication Date:  2013 Feb 
Date Detail:
Created Date:  2013-02-07     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0425746     Medline TA:  Med Phys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  020702     Citation Subset:  IM    
Affiliation:
School of Postgraduate Medicine, University of Hertfordshire, College Lane, Hatfield AL10 9AB, United Kingdom.
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