BMC Geriatrics 2009, 9:41doi:10.1186/1471-2318-9-41

Background
Cognition and mobility in older adults are closely associated and they decline together with aging. Studies evaluating associations between cognitive factors and gait performance in people with Mild Cognitive Impairment (MCI) are scarce. In this study, our aim was to determine whether specific cognitive factors have a more identifiable effect on gait velocity during dual-tasking in people with MCI.

Methods
Fifty-five participants, mean age 77.7 (SD=5.9), 45% women, with MCI were evaluated for global cognition, working memory, executive function, and attention. Gait Velocity (GV) was measured under a single-task condition (single GV) and under two dual-task conditions: 1) while counting backwards (counting GV), 2) while naming animals (verbal GV). Multivariable linear regression analysis was used to examine associations with an alpha-level of 0.05.

Results
Participants experienced a reduction in GV while engaging in dual-task challenges (p<0.005). Low executive function and working memory performances were associated with slow single GV (p=0.038), slow counting GV (p=0.017), and slow verbal GV (p=0.031). After adjustments, working memory was the only cognitive factor which remained significantly associated with a slow GV.

Conclusion
In older adults with MCI, low working memory performance was associated with slow GV. Dual-task conditions showed the strongest associations with gait slowing. Our findings suggest that cortical control of gait is associated with decline in working memory in people with MCI.