Dataset Information

Fractal analysis of gait in people with Parkinson's disease: three minutes is not enough.

ABSTRACT: BACKGROUND:The fractal dynamics of gait variability in people with Parkinson's disease has been studied by applying the detrended fluctuation analysis (DFA) to short time series (<200 strides). However, DFA is sensitive to time series length, and it is unclear if DFA results from short time series are reliable and if they reflect the fractal dynamics of longer time series. RESEARCH QUESTION:Is DFA reliable when applied to short time series? METHODS:We applied DFA to stride time series from five 3-min trials and one 15-min trial in 12 people with Parkinson's disease, 14 healthy older adults and 14 healthy young adults walking overground. Within each group, intraclass correlations (ICC 3,1) were performed to assess the reliability of i) the five 3-min trials together, ii) each 3-min trials to the 15-min trial, and iii) the first 150 strides from the 15-min trial to the full 15-min trial. RESULTS:Our three main findings are that 1) stride time ?-DFA values are not consistent from trial-to-trial for short stride time series, 2) stride time ?-DFA values from each 3-min trials are not consistent when compared to stride time ?-DFA values from a 15-min trial, and 3) stride time ?-DFA values from the first 150 strides of the 15-min trial are not consistent when compared to ?-DFA values from the full 15-min trial. SIGNIFICANCE:Our results confirm that ?-DFA values from 3-min walking trials are not reliable, and that they do not reflect the scale invariant properties of longer time series. This suggests that previous studies assessing the fractal dynamics of gait variability from about 3-min walking must be interpreted with caution. A major clinical implication is that DFA cannot be used to study gait in people unable to perform 500 strides continuously.

SUBMITTER: Marmelat V

PROVIDER: S-EPMC6545579 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Fractal analysis of gait in people with Parkinson's disease: three minutes is not enough.

Marmelat Vivien V Meidinger Ryan L RL

Gait & posture 20190226

<h4>Background</h4>The fractal dynamics of gait variability in people with Parkinson's disease has been studied by applying the detrended fluctuation analysis (DFA) to short time series (<200 strides). However, DFA is sensitive to time series length, and it is unclear if DFA results from short time series are reliable and if they reflect the fractal dynamics of longer time series.<h4>Research question</h4>Is DFA reliable when applied to short time series?<h4>Methods</h4>We applied DFA to stride ...[more]

PMID: 30909002

Similar Datasets

Project description:BackgroundHealthy gait dynamics are characterized by the presence of fractal, persistent stride-to-stride variations, which become more random with Parkinson's disease (PD). Rhythmic auditory stimulation with fractal beat-to-beat variations can change gait dynamics in people with PD toward more persistence.Research questionHow does gait in people with PD change when synchronizing steps with fractal melodic metronomes with different step-to-beat ratios, and which stimulus do they prefer?MethodsIn this cross-sectional study, 15 people with PD and 15 healthy older adults walked over-ground in three conditions: self-paced, paced by a fractal auditory stimulus with a 1:1 step-to-beat ratio ('metronome'), and fractal auditory stimulus with a 1:2 step-to-beat ratio ('music'). Gait dynamics were recorded with instrumented insoles, and detrended fluctuation analysis (DFA) was applied to the series of stride time intervals. Stimuli preference was assessed using Likert-like scales and open-ended questions. ANOVAs were used to compare mean, coefficient of variation, α-DFA, and the responses from the continuous Likert scales. Pearson correlations were used to assess the relationship between 'music' and 'metronome' enjoyment or difficulty with gait outcomes, and to determine the association between baseline α-DFA and changes due to the stimuli.ResultsOur major findings are that (i) stride-to-stride variations were more persistent with the 'metronome' compared to baseline for both groups, (ii) the effect was greater for people with lower α-DFA at baseline (i.e., more random stride-to-stride variations), and (iii) both groups found the 'metronome' less difficult to synchronize with.SignificanceThis study showed that people with PD and healthy older adults walk with higher statistical persistence in their stride-to-stride variations when instructed to synchronize their steps with a fractal stimulus. Participants with lower persistence at baseline benefited the most from the fractal 'metronome', highlighting the importance to develop patient-centered tests and interventions.

Dataset Information

Fractal analysis of gait in people with Parkinson's disease: three minutes is not enough.

Publications

Fractal analysis of gait in people with Parkinson's disease: three minutes is not enough.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets