The attentional demands of ambulating with an assistive device in older adults with Alzheimer's disease

Ambulation with a mobility aid is a unique real-life situation of multi-tasking. These simultaneous motor tasks place increased demands on executive function in healthy young and older adults, but the demands have not been evaluated in people with Alzheimer's disease (AD). Mobility problems are common among adults with AD, leading to provision of a mobility aid to optimize independent activity. The study objectives were: (i) to determine the dual-task cost (DTC) associated with the use of a mobility aid in straight and complex path walking, and (ii) to evaluate the association between executive function and ambulation with a mobility aid in older adults with AD and age-sex matched cognitively normal controls. Fourteen people (mean age ± SD, 72.6 ± 9.9 years) with a diagnosis of probable AD (MMSE range 12-25) and controls (mean age ± SD, 72.9 ± 9.5) walked at a self-selected pace and using a 4-wheeled walker in a 6 m straight path and a Figure of 8 Test. Ambulation with the walker in a straight path produced a low DTC that was not different between the groups. Ambulation with the 4-wheeled walker in the complex path produced a significantly different DTC in the group with AD at −38.1 ± 23.5% compared to −19.7 ± 21.4% (p = 0.041). Lower scores on executive function were associated with longer times across test conditions. Ambulation with a 4-wheeled walker, in particular maneuvering around obstacles, requires greater attentional costs in dementia. Future research should explore the timing for safely introducing mobility aids in AD and the role of improving executive function.