Comparing adaptive fractal and detrended fluctuation analyses of stride time variability: Tests of equivalence.

Background: Fractal analyses quantify self-similarities in stride-to-stride fluctuations over different time scales. Fractal exponents can be measured with adaptive fractal analysis (AFA) or detrended fluctuation analysis (DFA), though measurements obtained with the algorithms have not been directly compared.

Research Question: Are stride time fractal exponents measured with AFA and DFA algorithms equivalent?

Methods: Data from 50 participants with Parkinson's Disease (n = 15), age-similar healthy adults (n = 15) and healthy young adults (n = 20) were analyzed in this cross-sectional, observational study.