MATLAB and Signal Processing and Statistical Analysis Toolboxes (R2008b, MathWorks; Natick, Massachusetts) were used to implement MDFA and statistical testing.
MDFA allows us to quantify the dynamics of a frequency component with respect to its complexity.
MDFA of skin BFO, the method proposed in this study, could be used to assess the effectiveness of exercise interventions on enhancing microvascular function in people with SCI.
Using MDFA, we were able to characterize the nonlinear complexity of sacral skin BFO and detect that people with SCI had a lower complexity than nondisabled controls.
An important challenge in applying the MDFA to detect the complexity of a frequency component (e.
We intended to test the feasibility of using MDFA to assess microvascular dysfunction in people with SCI.
Unlike traditional methods, in which the normalized amplitude of a frequency component is used as a quantitative measure of the related control mechanism of BFO, MDFA provides information about the nonlinear complexity of a blood flow signal, which may be used to study the interactions among various blood flow control mechanisms and the influences of SCI on microvascular functions.