Effect of the Usage of Handrails on Gait Dynamics in People with Parkinson\u27s Disease

The purpose of this project is to determine if increasing body stability during handrails-use walking on a treadmill will increase the complexity of gait variability in patients with Parkinsons disease (PD). In young healthy participants, stride time-series of walking presents a pattern of complex variability, but this complexity critically decreases in patients with PD. Complexity is defined as an optimal state between too much regularity and too much irregularity, allowing the locomotor system to maintain robust performances while being able to adapt to perturbations. A possible explanation is that the decrease in complexity results from increased control mechanisms to avoid excessive postural instability, which is already impaired in PD patients. If the decrease in complexity observed in PD results from a more cautious gait in response to excessive postural instability, we expect that increasing their postural stability would be associated to increased level of complexity. One solution to increase body stability is to walk while holding treadmill handrails. Fifteen patients with PD, fifteen age-matched controls and fifteen healthy young adults will be recruited. Subjects will undergo clinical and functional tests, as well as two 15 min walking trials at comfortable speed, with and without holding treadmill handrails. Analysis of the stride-to-stride fluctuations will be conducted using detrended fluctuations analysis. In addition, deviations of the center of mass will be estimated by deviations of a marker placed on the lower back of participants. We anticipate lower deviations in the anterior-posterior and the medio-lateral planes when participants hold onto the handrails