Challenges encountered during complex walking tasks in people with Parkinson's disease: manipulating obstacle characteristics and configuration

Abstract

A range of motor and non-motor symptoms are present in Parkinson's disease (PD), including visual disturbance, cognitive decline, depression, and gait impairment. Addressing and managing these symptoms is important to ensure people with PD maintain a sufficient level of mobility and independence. People with PD at an increased risk of falls compared to the general older population due to pathology-associated symptoms. Falls often occur during ambulation with tripping a common precipitator of falls. As such it is important to understand the challenges and increased demands faced by people with PD during complex walking tasks. The configuration of an obstacle and associated dimensions will affect the complexity and locomotor challenge of the task. Safe completion of the task will depend on appropriate visual scanning of the upcoming path and adequate motor planning. Online gait adjustments may be required, particularly during the approach and sufficient foot clearance and placement completing the crossing steps. Increasing the height of obstacles results in greater challenge to balance and long obstacles not exceeding usual step length are suggested to act as a visual cue prompting adequate step length. Encountering multiple obstacles of varied height and depth within a single walking path may present a more challenging task for people with PD who have difficulty attending to multiple tasks (poor executive function), do not visually scan areas beyond the current task, ambulate at a reduced velocity, and often walk with a short, shuffling gait. Initiating gait adaptations to overcome obstacles of varying height and depth requires real-time gait modifications which may present added challenge for people with PD. Justification and Rationale: Obstacles of incremental height result in a graded change in gait adaptations. However, little is known about the adaptations to gait and vision when negotiating obstacles of graded depth (i.e. 15cm<30cm<45cm). By monitoring multiple systems simultaneously (visual input and neuromuscular control of gait), the findings from this study will enhance our understanding of motor control strategies during complex walking tasks in people with PD. Aim: The aims of this research project are to: (a) investigate how people with PD adapt their gait in response to obstacles of graded height and depth; (b) explore how gait adaptations during the approach and crossing steps vary depending on the configuration and dimensions of ground-based obstacles. Methods: A minimum of 50 participants will be recruited: 25 people with PD and 25 older adults without PD. All participants will be asked to attend Human Movement Research Laboratory (UNESP-Bauru) for a single session during which a variety of demographic, clinical (PD participants only), visual and functional performance outcomes will be obtained. Participants will complete a number of walking conditions combing multiple obstacles of graded height and depth. The following measures will be obtained: temporal-spatial stepping characteristics, lower limb joint angles, foot clearance, lower limb muscular activity and visual behaviour. Additional collaboration with ongoing projects: Dr. Lisa Alcock will collaborate with ongoing projects concerned focus on obstacle avoidance in people with PD, considering cortical control (FAPESP 2017/19516-8), added cognitive demand (FAPESP 2016/14950-9) and the effect of levodopa (FAPESP 2017/27067-9). Impact generated from proposed project: A systematic literature review exploring the adaptations in gait in response to obstacle characteristics; two scientific manuscripts concerning the locomotor adaptations observed in people with PD in response to obstacles of graded size and varying configuration; conference abstracts arising from the project; lectures about new insights into locomotor function in people with PD; and visits to other research groups of São Paulo State (USP-Ribeirão Preto and UNESP-Rio Claro). (AU)