Influence of different environmental contexts on gait parameters in patients with Parkinson's disease

Context: Parkinson's disease (PD) is the second most common neurodegenerative disease with an estimated 9.4 million people diagnosed with it in 2020. It has an influence on people's daily lives, notably by modifying their gait. One of the most severe gait impairment is freezing of gait which further reduces the patients' mobility and independence. Objective: The goal of this thesis was to identify how the gait parameters of people with PD are influenced by specific environmental conditions. This thesis is part of the long-term objective to use an active pelvis orthosis for assistive and rehabilitative natures and to develop a real-time assistance for the patient. Experiments: Six patients, including three with freezing of gait (FOG), walked in four different environmental conditions: (1) 10 meters straight on flat ground, (2) 10 meters straight on gym mattresses, (3) 10 meters straight on flat ground with a doorway at mid-way and (4) 2x5 meters with a tight U-turn between the two. The control condition corresponds to the 10 meters straight on flat ground. Results: The statistical analysis showed that both (1) and (2) had an effect on the stride time and cadence for patients' most and least affected side by PD. It also showed that both environmental conditions had an effect on their velocity and their least affected side's step length. While no significant effects were found for freezers (patients with PD who experience FOG), they had longer stride, stance and swing time as well as slower cadence and smaller step length for both sides and both environmental conditions compared to non-freezers (patients with PD without FOG). Freezers' velocity was also slower for both environmental conditions. The visual analysis showed that freezers increased their stride and stance time during the crossing of a doorway and decreased their swing time. Freezers kept their stride and stance time constant before the turn while they decreased their swing time. For both (3) and (4), freezers' phasing was out of sync before and during the doorway crossing. Non-freezers increased their stride and stance time before and during the doorway crossing while decreasing their stride time. For (4), non-freezers increased their stride time before the turn and increased their stance time during the turn. They also increased their swing time before the turn and decreased it during the turn. Discussion: The stride time, cadence and velocity were significantly influenced by irregular surfaces. When passing through a doorway, the stride, stance and swing time were influenced and the swing time could be used as an indicator that a turn will occur soon. More specifically for freezers, the phasing showed great variability before either the doorway was crossed or the turn was performed. These metrics thus show some promises for providing real-time assistance to people with PD.