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

Abstract

SignificanceDespite an improvement of temporal gait variability validity in the self-paced mode for healthy subjects, the large systematic and random errors between overground and self-paced treadmill walking prohibit meaningful gait variability observations in patients with Parkinson's disease using self-paced treadmills.

A step towards understanding fatigue and the cost of walking in persons with multiple sclerosis and rheumatoid arthritis

“…Participants were provided with real-time feedback about their walking speed using the virtual environment and instructed to find a comfortable pace within a ±5% range of the calculated speed. For details about the self-paced algorithm used we refer to 147,157 and Supplementary File 1.…”

“…Several limitations to this study should be considered when interpreting the findings. First, the algorithm used for adjusting the treadmill speed in self-paced conditions may affect variability of self-paced conditions and care should therefore be taken when generalizing these findings to settings in which a different self-paced algorithm or experimental set-up from the current is used 136,157,[169][170][171] . Similarly, the presence of visual optic flow of the 180 degrees cylindrical screen of the CAREN system may also affect walking speed and thus walking biomechanics and energetics 172 .…”

“…For example, the belt speed increased when the participant was walking in front of the treadmill, with the acceleration increasing as the participant walked more towards the front of the treadmill. The sensitivity of the self-paced algorithm was set to default (i.e., 1) as this has been shown to best match self-paced variability to overground walking variability in healthy individuals 157 .…”