Gait Complexity and Regularity Are Differently Modulated by Treadmill Walking in Parkinson's Disease and Healthy Population

Abstract

Variability raises considerable interest as a promising and sensitive marker of dysfunction in physiology, in particular in neurosciences. Both internally (e.g., pathology) and/or externally (e.g., environment) generated perturbations and the neuro-mechanical responses to them contribute to the fluctuating dynamics of locomotion. Defective internal gait control in Parkinson's disease (PD), resulting in typical timing gait disorders, is characterized by the breakdown of the temporal organization of stride duration variability. Influence of external cue on gait pattern could be detrimental or advantageous depending on situations (healthy or pathological gait pattern, respectively). As well as being an interesting rehabilitative approach in PD, treadmills are usually implemented in laboratory settings to perform instrumented gait analysis including gait variability assessment. However, possibly acting as an external pacemaker, treadmill could modulate the temporal organization of gait variability of PD patients which could invalidate any gait variability assessment. This study aimed to investigate the immediate influence of treadmill walking (TW) on the temporal organization of stride duration variability in PD and healthy population. Here, we analyzed the gait pattern of 20 PD patients and 15 healthy age-matched subjects walking on overground and on a motorized-treadmill (randomized order) at a self-selected speed. The temporal organization and regularity of time series of walking were assessed on 512 consecutive strides and assessed by the application of non-linear mathematical methods (i.e., the detrended fluctuation analysis and power spectral density; and sample entropy, for the temporal organization and regularity of gait variability, respectively). A more temporally organized and regular gait pattern seems to emerge from TW in PD while no influence was observed on healthy gait pattern. Treadmill could afford the necessary framework to regulate gait rhythmicity in PD. Overall, the results support the hypothesis of a greater dependence to regulatory inputs as an explanatory factor of treadmill influence observed in PD. Also, since treadmill misrepresents the gait as more healthy than it is, the present findings underline that gait analysis using treadmill devices should be cautiously considered in PD and especially for gait variability assessment in gait lab.

Self-paced treadmills do not allow for valid observation of linear and non-linear gait variability outcomes in patients with Parkinson’s disease

“…The regulatory effect of motorized treadmills, that act as an external pacemaker, on patients with Parkinson's disease has been documented before. Similarly to Warlop and colleagues, we find markedly elevated levels of temporal magnitude of variability in PD during treadmill walking that is absent in healthy controls [49]. Also, the generally poorer validity in the PD for all outcomes indicates that treadmill use is particularly problematic for the assessment of patient cohorts with sensory-motor deficits.…”

Immersive Virtual Reality to Restore Natural Long-Range Autocorrelations in Parkinson’s Disease Patients’ Gait During Treadmill Walking

“…A power analysis was computed using the data of Warlop et al (2018). Authors compared PD patients' temporal organization of stride duration variability using α exponent calculated with the DFA during two conditions: overground walking and treadmill walking.…”

Gait Dynamics in Parkinson’s Disease: Short Gait Trials “Stitched” Together Provide Different Fractal Fluctuations Compared to Longer Trials

“…First, participants in this study walked over-ground, but as mentioned previously, previous studies investigating the reliability of stride time DFA values focused on treadmill-walking. In addition, while over-ground walking is ecologically relevant, treadmill walking is important in both research and clinical settings, and can potentially improve gait in people with PD ( Frenkel-Toledo et al, 2005 ; Earhart and Williams, 2012 ; Mirelman et al, 2016 ; Warlop et al, 2018 ). Further studies should therefore investigate the potential of the stitching procedure during treadmill walking.…”

“…Importantly, changes in scaling exponent are independent from changes in average stride time and in the magnitude of fluctuations. Neurological dysfunctions affecting neural rhythm generation also alter the temporal ordering of stride-to-stride fluctuations ( Hausdorff et al, 1997 ; Hove et al, 2012 ; Uchitomi et al, 2013 ; Ota et al, 2014 ; Moon et al, 2016 ; Warlop et al, 2016 , 2018 ). In particular, patients with PD exhibit less persistent fluctuations in stride time series compared to age-matched controls, suggesting greater impairments in the regulation of gait timing.…”