Using Complexity and Spectral Analyses of Noninvasive LDF Signals in Patients with Metabolic Syndrome

Abstract

This study performed skin-surface measurements with the aim of verifying if complexity and spectral analyses applied to laser-Doppler-flowmetry (LDF) signals can be used to discriminate control subjects and patients with metabolic syndrome (MetS) and patients with premetabolic syndrome (pre-MetS). The study participants (n=142) were assigned to three age-matched groups based on the application of MetS criteria. Beat-to-beat analysis was performed to obtain the mean blood flow (DC), and then approximate entropy (ApEn) values for the 10-minute DC sequences (DC_ApEn) were calculated to evaluate the signal complexity. The wavelet transform was applied and yielded periodic oscillations with five characteristic frequency peaks (defined as FR1–FR5) whose relative energy contributions (RECs) were calculated. DC_ApEn was significantly smaller in MetS and pre-MetS (with one or two Mets factors) patients than in controls, whereas there were no significant differences in DC. The REC of FR1 was significantly smaller while the REC of FR4 was significantly larger in pre-MetS than in MetS. These results indicate the presence of significant differences in ApEn and spectral indexes, which may be partly attributable to changes in microcirculatory regulatory activities accompanying the progression of MetS. The present findings may be pertinent to the early detection of the microcirculatory impairments associated with MetS.

Laser Doppler Fluximetry in Cutaneous Vasculature: Methods for Data Analyses

“…SampEn was developed as an alternative measure to Approximate Entropy (ApEn), a measure of the randomness of a signal, as it can reduce bias associated with ApEn which can suggest greater signal regularity than actually exists [32,50]. In one study, LDF signals were found to have decreased complexity, as assessed by ApEn, in populations with metabolic syndrome and premetabolic syndrome compared to healthy controls [27]. SampEn has also been reported to be increased in patients with systemic sclerosis in response to localized heating [51].…”

“…Nonlinear Analysis (Single Scale) Several nonlinear measures have been used to analyze LDF data [22,27,28]. Here we discuss two of these measures which have been used in several LDF studies: LZC and sample entropy.…”

Machine Learning Analyses Revealed Distinct Arterial Pulse Variability According to Side Effects of Pfizer-BioNTech COVID-19 Vaccine (BNT162b2)

“…For example, HR variability and BP variability indices have been used for monitoring changes in the regulatory activities induced by aging and disease [ 27 , 28 ]. For the vascular properties and blood flow, changes in the cardiovascular variability indices were also found to be correlated with the responses induced by disease or external stimulation [ 18 , 29 ]. For example, the pulse-variability indices were found to be higher in subjects with metabolic syndrome than in the controls, illustrating a stronger response to the changes in vascular stiffness and resistance induced by metabolic syndrome, that comprise a cluster of vascular risk factors [ 19 ].…”

Application of Spectral Methods of Analysis for Description of Ultradian Biorhythms at the Levels of Physiological Systems, Cells and Molecules (Review)

“…A detailed study of the molecular mechanisms of the development of endothelial dysfunction in DM2 will make it possible to find new therapeutic approaches to prevent the development of complications of DM2, as well as expand the use of the assessment of the frequency response of oscillations in the microcirculation rate in the early diagnosis of DM2. It has been found that in patients with DM2, there is a decrease in both absolute and relative (normalized to the total power over the spectrum) amplitudes of oscillations in the rate of skin microcirculation in NOindependent endothelial, neurogenic, and myogenic rhythms compared with conditionally healthy volunteers, and a complex modification of the response also occurs for a thermal sample, depending on the heating temperature [3,180,213,214]. In addition, the dependence of the severity of oscillations in the myogenic rhythm on the lipid profile and the severity of DM2 was found [187].…”