Abstract
Background/Objectives: Physical function indicators, including gait velocity, stride time and step length, are linked to neural and cognitive function, morbidity and mortality. Whereas cross-sectional associations are well documented, far less is known about long-term patterns of cognitive change as related to objective indicators of mobility-related physical function.Methods: Using data from the Victoria Longitudinal Study, a long-term investigation of biological and health aspects of aging and cognition, we examined three aspects of cognition-physical function linkages in 121 older adults. First, we examined a simple marker of physical function (3 m timed-walk) as a predictor of cross-sectional differences and up to 25-year change for four indicators of cognitive function. Second, we tested associations between two markers of gait function derived from the GAITRite system (velocity and stride-time variability) and differences and change in cognition. Finally, we evaluated how increasing cognitive load during GAITRite assessment influenced the associations between gait and cognition.Results: The simple timed-walk measure, commonly used in clinical and research settings, was a minor predictor of change in cognitive function. In contrast, the objectively measured indicator of walking speed significantly moderated long-term cognitive change. Under increasing cognitive load, the moderating influence of velocity on cognitive change increased, with increasing variability in stride time also emerging as a predictor of age-related cognitive decline.Conclusion: These findings: (a) underscore the utility of gait as a proxy for biological vitality and for indexing long-term cognitive change; and (b) inform potential mechanisms underlying age-related linkages in physical and cognitive function.
Highlights
Differences and change in cognition have recently been explained by functional biomarkers—select biological processes that systematically decline with age, index functional capacity of various bodily systems and can be objectively measured (Anstey, 2008; Dixon, 2011; MacDonald et al, 2011)
The central and peripheral nervous systems share associations with gait function, with diminished gait velocity or increased variability linked to CNS impairments; subclinical infarcts and white matter abnormalities have been linked to indicators of gait function (Rosano et al, 2007)
Using multi-wave data from the Victoria Longitudinal Study (VLS), we examined gait-cognition linkages guided by three research objectives
Summary
Differences and change in cognition have recently been explained by functional biomarkers—select biological processes that systematically decline with age, index functional capacity of various bodily systems and can be objectively measured (Anstey, 2008; Dixon, 2011; MacDonald et al, 2011). Measures of gait speed, assessed in various ways (timed 3 m walk, computerized walkway), have been linked to cognitive and functional impairment (Rosano et al, 2008), health (Abellan Van Kan et al, 2009), and mortality risk (Studenski et al, 2011). Among the reasons for observed links between gait and deleterious age-related outcomes, individual differences in gait may reflect the integrity of underlying organ systems including respiratory, vascular, nervous, circulatory and musculoskeletal (Abellan Van Kan et al, 2009; Studenski et al, 2011). Beyond the relative health of individual organ systems, walking places demands on energy metabolism, with links between diminished gait speed and various age-related outcomes due to higher metabolic costs for the elderly (Mian et al, 2006). A better understanding of how changes in various bodily systems and the CNS influence mobility constraints may inform our understanding of age-CNS-cognition associations (Rosso et al, 2013)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
