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Updated: May 31, 2026
Spatial Temporal Analysis of Fieldwise Flow in Microvasculature
Published on: November 18, 2019
Multiscale analysis of microvascular blood flow: a multiscale entropy study of laser Doppler flowmetry time series
Anne Humeau1, Guillaume Mahé, François Chapeau-Blondeau
1Laboratoire d’Ingénierie des Systèmes Automatisés, Université d’Angers, 49000 Angers, France. anne.humeau@univangers.fr
Insights
This study investigated multiscale entropy in peripheral cardiovascular signals (laser Doppler flowmetry). Findings suggest the nonmonotonic behavior observed originates centrally, likely influenced by cardiac activity.
Area of Science:
- Cardiovascular Physiology
- Biomedical Signal Processing
- Complexity Science
Background:
- Cardiovascular system (CVS) regulation involves numerous processes across multiple temporal scales.
- Multiscale analysis is crucial for understanding CVS interdependencies, with most studies focusing on central heart rate variability (HRV).
- Peripheral CVS analysis, using signals like laser Doppler flowmetry (LDF), remains less explored regarding multiscale properties.
Purpose of the Study:
- To confirm recent findings of nonmonotonic multiscale entropy in LDF signals.
- To investigate the origins of this unique multiscale behavior in peripheral CVS data.
- To compare LDF multiscale entropy with that of HRV signals.
Main Methods:
- Processed 12 simultaneous LDF signals from the forearms of six healthy subjects.
- Applied physiological scales-based filters to isolate specific frequency bands related to physiological activities.
- Analyzed multiscale entropy before and after filtering to identify signal origins.
Main Results:
- Confirmed a nonmonotonic evolution of multiscale entropy in LDF signals, differing from HRV.
- Simultaneous recordings from bilateral sites suggested a probable central origin for the observed nonmonotonic behavior.
- Filtering results indicated that cardiac activity may dominate the origins of the distinctive scales in LDF signals.
Conclusions:
- The nonmonotonic multiscale entropy behavior in peripheral LDF signals likely stems from central cardiovascular regulation.
- Cardiac activity appears to be a significant contributor to the complex temporal dynamics observed in peripheral LDF.
- Further research into multiscale analysis of peripheral signals can provide deeper insights into CVS regulation.
Abstract:
Processes regulating the cardiovascular system (CVS) are numerous. Each possesses several temporal scales. Their interactions lead to interdependences across multiple scales. For the CVS analysis, different multiscale studies have been proposed, mostly performed on heart rate variability signals (HRV) reflecting the central CVS; only few were dedicated to data from the peripheral CVS, such as laser Doppler flowmetry (LDF) signals. Very recently, a study implemented the first computation of multiscale entropy for LDF signals. A nonmonotonic evolution of multiscale entropy with two distinctive scales was reported, leading to a markedly different behavior from the one of HRV. Our goal herein is to confirm these results and to go forward in the investigations on origins of this behavior. For this purpose, 12 LDF signals recorded simultaneously on the two forearms of six healthy subjects are processed. This is performed before and after application of physiological scales-based filters aiming at isolating previously found frequency bands linked to physiological activities. The results obtained with signals recorded simultaneously on two different sites of each subject show a probable central origin for the nonmonotonic behavior. The filtering results lead to the suggestion that origins of the distinctive scales could be dominated by the cardiac activity.
