Dual-Task Walking Across Task Combinations in Older Adults With Mild Cognitive Impairment

Difficulty performing concurrent tasks while walking, or dual-task walking, may have negative consequences for safe and independent functional mobility among older adults. Older adults with amnestic mild cognitive impairment (aMCI) may demonstrate slower gait and worse cognitive task speed or accuracy during dual-task conditions. However, prior research has not consistently quantified cognitive performance during dual-task walking, and it is unclear whether changes in dual-task performance are consistent across different task combinations. The purpose of this study was to compare cognitive and gait performance during dual-task conditions in older adults with aMCI and those with normal cognition (NC).

An observational cross-sectional study was conducted with 40 community-dwelling older adults, aged 70-95 years with aMCI (n = 18) and NC (n = 22). Gait (self-paced, fast-paced) and cognitive task performance (serial 3, serial 7 subtraction) were quantified during single-task and dual-task conditions. Linear mixed-effects models with a random effect for participants were used to quantify differences between groups (aMCI vs NC) and task conditions (single-task vs dual-task). Further analysis was performed to quantify cognitive performance and gait changes during more challenging dual-task combinations.

Across task combinations, gait performance declined for both groups during dual-task conditions. Gait speed was slower during dual-task conditions than single-task conditions in both the NC and aMCI groups for all task combinations. Older adults with aMCI performed worse on cognitive tasks than those with NC during both single-task and dual-task conditions. Correct response rate was slower for people with aMCI than NC during both single-task and dual-task conditions.

Dual-task activities, combining gait and cognitive processes, are associated with fall risk and are therefore commonly evaluated in physical therapy care for older adults. Both aMCI and NC groups walked slower during dual-task conditions, but the aMCI group experienced changes with a lower cognitive load. This highlights the importance of quantifying both cognitive and gait performance during dual-task assessments. Changes in cognitive task and gait performance were consistent across different dual-task combinations, which could inform dual-task interventions.