Generalized fractal dimensions of laser Doppler flowmetry signals recorded from glabrous and nonglabrous skin

Authors

  • Buard Benjamin,

    1. Groupe ESAIP, 18 rue du 8 mai 1945, BP 80022, 49180 Saint Barthélémy d’Anjou Cedex, France and Laboratoire d’Ingénierie des Systèmes Automatisés (LISA), Université d’Angers, 62 Avenue Notre Dame du Lac, 49000 Angers, France
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    • a)

      Telephone: +33(0)241966510; Fax: +33(0)241966511; Electronic mail: bbuard@esaip.org

  • Mahé Guillaume,

    1. Laboratoire de Physiologie et d’Explorations Vasculaires, UMR CNRS 6214-INSERM 771, Centre Hospitalier Universitaire d’Angers, 49033 Angers Cedex 01, France
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  • Chapeau-Blondeau François,

    1. Laboratoire d’Ingénierie des Systèmes Automatisés (LISA), Université d’Angers, 62 Avenue Notre Dame du Lac, 49000 Angers, France
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  • Rousseau David,

    1. Laboratoire d’Ingénierie des Systèmes Automatisés (LISA), Université d’Angers, 62 Avenue Notre Dame du Lac, 49000 Angers, France
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  • Abraham Pierre,

    1. Laboratoire de Physiologie et d’Explorations Vasculaires, UMR CNRS 6214-INSERM 771, Centre Hospitalier Universitaire d’Angers, 49033 Angers Cedex 01, France
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  • Humeau Anne

    1. Laboratoire d’Ingénierie des Systèmes Automatisés (LISA), Université d’Angers, 62 Avenue Notre Dame du Lac, 49000 Angers, France
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  • 0094-2405/2010/37(6)/2827/10/$30.00

Abstract

Purpose

The technique of laser Doppler flowmetry (LDF) is commonly used to have a peripheral view of the cardiovascular system. To better understand the microvascular perfusion signals, the authors herein propose to analyze and compare the complexity of LDF data recorded simultaneously in glabrous and nonglabrous skin. Glabrous zones are physiologically different from the others partly due to the presence of a high density of arteriovenous anastomoses.

Methods

For this purpose, a multifractal analysis based on the partition function and generalized fractal dimensions computation is proposed. The LDF data processed are recorded simultaneously on the right and left forearms and on the right and left hand palms of healthy subjects. The signal processing method is first tested on a multifractal binomial measure. The generalized fractal dimensions of the normalized LDF signals are then estimated. Furthermore, for the first time, the authors estimate the generalized fractal dimensions from a range of scales corresponding to factors influencing the microcirculation flow (cardiac, respiratory, myogenic, neurogenic, and endothelial).

Results

Different multifractal behaviors are found between normalized LDF signals recorded in the forearms and in the hand palms of healthy subjects. Thus, the variations in the estimated generalized fractal dimensions of LDF signals recorded in the hand palms are higher than those of LDF signals recorded in the forearms. This shows that LDF signals recorded in glabrous zones may be more complex than those recorded in nonglabrous zones. Furthermore, the results show that the complexity in the hand palms could be more important at scales corresponding to the myogenic control mechanism than at the other studied scales.

Conclusions

These findings suggest that the multifractality of the normalized LDF signals is different on glabrous and nonglabrous skin. This difference may rely on the density of arteriovenous anastomoses and differences in nerve supply or biochemical properties. This study provides useful information for an in-depth understanding of LDF data and a more detailed knowledge of the peripheral cardiovascular system.

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