Assessing the Temporal Relationship Between Cognition and Gait: Slow Gait Predicts Cognitive Decline in the Mayo Clinic Study of Aging

BACKGROUND: The association between gait speed and cognition has been reported; however, there is limited knowledge about the temporal associations between gait slowing and cognitive decline among cognitively normal individuals. METHODS: The Mayo Clinic Study of Aging is a population-based study of Olmsted County, Minnesota, United States, residents aged 70-89 years. This analysis included 1,478 cognitively normal participants who were evaluated every 15 months with a nurse visit, neurologic evaluation, and neuropsychological testing. The neuropsychological battery used nine tests to compute domain-specific (memory, language, executive function, and visuospatial skills) and global cognitive z-scores. Timed gait speed (m/s) was assessed over 25 feet (7.6 meters) at a usual pace. Using mixed models, we examined baseline gait speed (continuous and in quartiles) as a predictor of cognitive decline and baseline cognition as a predictor of gait speed changes controlling for demographics and medical conditions. RESULTS: Cross-sectionally, faster gait speed was associated with better performance in memory, executive function, and global cognition. Both cognitive scores and gait speed declined over time. A faster gait speed at baseline was associated with less cognitive decline across all domain-specific and global scores. These results were slightly attenuated after excluding persons with incident mild cognitive impairment or dementia. By contrast, baseline cognition was not associated with changes in gait speed. CONCLUSIONS: Our study suggests that slow gait precedes cognitive decline. Gait speed may be useful as a reliable, easily attainable, and noninvasive risk factor for cognitive decline.