Effect of Learning to Use a Mobility Aid on Gait and Cognitive Demands in People with Mild to Moderate Alzheimer's Disease: Part II - 4-Wheeled Walker.

Background: Cognitive deficits and gait problems are common and progressive in Alzheimer's disease (AD). Prescription of a 4-wheeled walker is a common intervention to improve stability and independence, yet can be associated with an increased falls risk. Objectives: 1) To examine changes in spatial-temporal gait parameters while using a 4-wheeled walker under different walking conditions, and 2) to determine the cognitive and gait task costs of walking with the aid in adults with AD and healthy older adults. Methods: Twenty participants with AD (age 79.1 +/- 7.1 years) and 22 controls (age 68.5 +/- 10.7 years) walked using a 4-wheeled walker in a straight (6 m) and Figure of 8 path under three task conditions: single-task (no aid), dual-task (walking with aid), and multi-task (walking with aid while counting backwards by ones). Results: Gait velocity was statistically slower in adults with AD than the controls across all conditions (all p values <0.025). Stride time variability was significantly different between groups for straight path single task (p = 0.045), straight path multi-task (p = 0.031), and Figure of 8 multi-task (0.036). Gait and cognitive task costs increased while multi-tasking, with performance decrement greater for people with AD. None of the people with AD self-prioritized gait over the cognitive task while walking in a straight path, yet 75% were able to shift prioritization to gait in the complex walking path. Conclusion: Learning to use a 4-wheeled walker is cognitively demanding and any additional tasks increases the demands, further adversely affecting gait. The increased cognitive demands result in a decrease in gait velocity that is greatest in adults with AD. Future research needs to investigate the effects of mobility aid training on gait performance.