title: Detrended fluctuation analysis of laser Doppler flowmetry time series.
abstract: Detrended fluctuation analysis (DFA) of laser Doppler flow (LDF) time series appears to yield improved prognostic power in microvascular dysfunction, through calculation of the scaling exponent, alpha. In the present study the long lasting strenuous activity-induced change in microvascular function was evaluated by DFA in basketball players compared with sedentary control. Forearm skin blood flow was measured at rest and during local heating. Three scaling exponents, the slopes of the three regression lines, were identified corresponding to cardiac, cardio-respiratory and local factors. Local scaling exponent was always approximately one, alpha=1.01+/-0.15, in the control group and did not change with local heating. However, we found a broken line with two scaling exponents (alpha(1)=1.06+/-0.01 and alpha(2)=0.75+/-0.01) in basketball players. The broken line became a single line having one scaling exponent (alpha(T)=0.94+/-0.01) with local heating. The scaling exponents, alpha(2) and alpha(T), smaller than 1 indicate reduced long-range correlation in blood flow due to a loss of integration in local mechanisms and suggest endothelial dysfunction as the most likely candidate. Evaluation of microvascular function from a baseline LDF signal at rest is the superiority of DFA to other methods, spectral or not, that use the amplitude changes of evoked relative signal.
authors: Department of Biophysics, Faculty of Medicine, Eskişehir Osmangazi University, 26480 Eskişehir, Turkey. hesen@ogu.edu.tr
authors: Ferhan
authors: F
authors: Esen
authors: Gülsün Sönmez
authors: GS
authors: Aydin
authors: Hamza
authors: H
authors: Esen
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D005080:Exercise Test; D017709:Fractals; D006801:Humans; D006940:Hyperemia; D017078:Laser-Doppler Flowmetry / Q000379:methods*; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D012867:Skin / Q000098:blood supply; D013269:Stochastic Processes; D013997:Time Factors; D055815:Young Adult