Assessing the temporal organization of walking variability: A systematic review and consensus guidelines on detrended fluctuation analysis

Deepak K. Ravi, Vivien Marmelat, William R. Taylor, Karl M. Newell, Nick Stergiou, Navrag B. Singh

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Human physiological signals are inherently rhythmic and have a hallmark feature in that even distant intrasignal measurements are related to each other. This relationship is termed long-range correlation and has been recognized as an indicator of the optimal state of the observed physiological systems, among which the locomotor system. Loss of long-range correlations has been found as a result of aging as well as disease, which can be evaluated with detrended fluctuation analysis (DFA). Recently, DFA and the scaling exponent α have been employed for understanding the degeneration of temporal regulation of human walking biorhythms in, for example, Parkinson disease (PD). However, heterogeneous evidence on scaling exponent α values reported in the literature across different population groups has put into question what constitutes a healthy physiological pattern. Therefore, the purpose of this systematic review was to investigate the functional thresholds of scaling exponent α in young vs. older adults, as well as between patients with PD and age-matched asymptomatic controls. Aging and PD exhibited a negative effect size (i.e., led to decreased long-range correlations) of −0.20 and −0.53, respectively. Our meta-analysis based on 14 studies provides evidence that a mean scaling exponent α threshold of 0.86 [2 standard error (0.76, 0.96)] is able to optimally discriminate temporal organization of stride interval between young and old, whereas 0.82 (0.72, 0.92) differentiates patients with PD and age-matched asymptomatic controls. The optimal thresholds presented in this review together with the consensus guidelines for using DFA might allow a more sensitive and reliable application of this metric for understanding human walking physiology than has been achieved to date.

Original languageEnglish (US)
Article number562
JournalFrontiers in Physiology
Volume11
DOIs
StatePublished - 2020

Keywords

  • Aging
  • Detrended fluctuation analysis
  • Fractal fluctuations
  • Fractal temporal structures
  • Gait variability
  • Long-range correlations
  • Parkinson disease
  • Stride interval variability

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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