Stride-to-stride time intervals are independently affected by the temporal pattern and probability distribution of visual cues

• Published in: Neuroscience letters 2023-01, Vol.792, p.136909, Article 136909
• Main Authors: Raffalt, Peter C., Sommerfeld, Joel H., Stergiou, Nick, Likens, Aaron D.
• Format: Article
• Language: English
• Subjects: Cues; Fractal: Gait; Gait; Healthy Volunteers; Humans; Likelihood Functions; Metronome; Paced Walking; Variability; Visual Cues; Walking
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2022.136909

•Investigated paced walking with visual cues.•Systematically manipulated autocorrelation and probability distribution of visual cues.•Stride intervals tend to match the autocorrelation of visual cues.•Stride interval autocorrelations are reduced by non-Gaussian visual cues.•Autocorrelation and probability distributions exert independent effects of stride-to-stride gait variability. The temporal structure of the variability of the stride-to-stride time intervals during paced walking is affected by the underlying autocorrelation function (ACF) of the pacing signal. This effect could be accounted for by differences in the underlying probability distribution function (PDF) of the pacing signal. We investigated the isolated and combined effect of the ACF and PDF of the pacing signals on the temporal structure of the stride-to-stride time intervals during visually guided paced overground walking. Ten young, healthy participants completed four walking trials while synchronizing their footstep to a visual pacing signal with a temporal pattern of either pink or white noise (different ACF) and either a Gaussian or normal probability distribution (different PDF). The scaling exponent from the Detrended Fluctuation Analysis was used to quantify the temporal structure of the stride-to-stride time intervals. The ACF and PDF of the pacing signals had independent effects on the scaling exponent of the stride-to-stride time intervals. The scaling exponent was higher during the pink noise pacing trials compared to the white noise pacing trials and higher during the trials with the Gaussian probability distribution compared to the uniform distribution. The results suggest that the sensorimotor system in healthy young individuals has an affinity towards external cues with a pink noise pattern and a Gaussian probability distribution during paced walking.