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The results suggest declining walking speed as a precursor to declining engagement in physical activity, but the converse association was not evident. Improving walking speed may be a method to increase physical activity among elderly individuals.

Objective measures of community mobility are advantageous for capturing life-space activity. In contrast to subjective, self-reported approaches, GPS-derived objective measures leverage passive, real-time data collection techniques to mitigate recall bias and minimize participant burden. We present methods to quantify community mobility among a sample of 164 community-dwelling older adults (Mean age=77.3±6.5) from a physical therapy intervention aimed at improving walking ability. We characterized community mobility using activity space metrics (e.g., standard deviation ellipse (SDE) area), timing (e.g., time outside home), and shape (e.g., SDE compactness). We will discuss challenges and solutions to generating these metrics as well as their associations with physical and cognitive performance. Time outside of home and SDE area, but not SDE compactness, were correlated with better performance on the 6-Minute Walking Test and Trail-Making Test (Part B) (ρ=.20-.23, p’s<.05). These findings will aid in understanding which community mobility measures are associated with functional capacity.

Background: Sleep problems may contribute to the disproportionate burden of Alzheimer’s disease and related dementias (ADRD) among African Americans (AAs). Objective: To examine the role of sleep problems in contributing to cognitive function and clinically adjudicated cognitive impairment in a predominantly AA sample. Methods: This study (n = 216, 78.8% female; mean age = 67.7 years) examined associations between 1) the level (i.e., measured in 2018) and 2) change over time (from 2013 to 2018; n = 168) in actigraphy-assessed sleep with domain-specific cognitive function and clinically adjudicated cognitive impairment (2018) in a community-dwelling, predominantly AA (96.9%) sample. A comprehensive cognitive battery assessed global cognitive function (3MS) and domain-specific cognitive function (attention, visuo-spatial ability, language, delayed recall, immediate recall, and executive function) in 2018. Sleep was measured in 2013 and 2018 via actigraphy. Results: Higher sleep efficiency and less wakefulness after sleep onset (WASO; measured in 2018) were associated with greater attention, executive function, and visuospatial ability. Increases in sleep efficiency between 2013 and 2018 were associated with better executive function, language, immediate recall, and visuospatial ability, whereas increases in WASO (2013–2018) were associated with poorer attention, executive function, and visuospatial ability. Level or change in sleep duration were not associated with domain-specific cognitive function, nor were any sleep measures associated with clinically adjudicated cognitive impairment. Conclusion: In a predominantly AA sample of older adults, both the level and change (i.e., worsening) of sleep efficiency and WASO were associated with poorer cognitive function. Improving sleep health may support ADRD prevention and reduce health disparities.

Background and ObjectivesMany cross-sectional studies have confirmed a link between gait speed and cognitive function. However, it is unknown whether cognitive function plays a role in the onset of major mobility disability (MMD) and if the effects are independent of physical function. This study examined cognitive and physical function as predictors of MMD across an average of 2.6 years of follow-up in community-dwelling older adults with compromised mobility.Research Design and MethodData were collected from 1,635 participants in the Lifestyle Interventions and Independence for Elders (LIFE) study ages 70–89 years free of MMD at baseline. MMD was assessed every 6 months and defined as the inability to walk 400 m in ≤15 min without assistance or sitting. Cognitive function was assessed at baseline, 18 months, and 24 months using a cognitive battery categorized into four domains: global cognitive function, processing speed, verbal memory, and executive function.ResultsAcross the study duration of 2.6 years, 536 participants (32.8%) developed MMD. Cox Proportional Hazard models indicated a protective relationship for higher baseline processing speed (Hazard Ratio [HR] per standard deviation: 0.86, p = .006), executive function (HR: 0.86, p = .002), and global cognition (HR: 0.85, p = .001) on incidence of MMD adjusted for demographics, intervention, and comorbidities. Results were not significant after adjustment for gait speed. In adjusted longitudinal models, a positive change in processing speed was significantly associated with reduced risk of MMD (HR: 0.52, p < .001) while other domains were not.Discussion and ImplicationsIn the LIFE study, processing speed at baseline and follow-up was a significant predictor of subsequent MMD although the observed association may be explained by physical function as reflected in gait speed. More studies are needed to understand how cognitive function, alone and in combination with physical function, influences risk of MMD.