title: Concurrent Indicators of Gait Velocity and Variability Are Associated with 25-Year Cognitive Change: A Retrospective Longitudinal Investigation.
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.
authors.affiliation: Department of Psychology, University of VictoriaVictoria, BC, Canada; Institute of Aging and Lifelong Health, University of VictoriaVictoria, BC, Canada.
authors.forename: Stuart W S
authors.initials: SW
authors.lastname: MacDonald
authors.affiliation: School of Exercise Science, University of Victoria Victoria, BC, Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Hundza
authors.affiliation: Department of Psychology, University of Victoria Victoria, BC, Canada.
authors.forename: Janet A
authors.initials: JA
authors.lastname: Love
authors.affiliation: Department of Psychology, University of VictoriaVictoria, BC, Canada; Institute of Aging and Lifelong Health, University of VictoriaVictoria, BC, Canada.
authors.forename: Correne A
authors.initials: CA
authors.lastname: DeCarlo
authors.affiliation: Department of Psychology, University of VictoriaVictoria, BC, Canada; Institute of Aging and Lifelong Health, University of VictoriaVictoria, BC, Canada.
authors.forename: Drew W R
authors.initials: DW
authors.lastname: Halliday
authors.affiliation: Department of Psychology, University of VictoriaVictoria, BC, Canada; Institute of Aging and Lifelong Health, University of VictoriaVictoria, BC, Canada.
authors.forename: Paul W H
authors.initials: PW
authors.lastname: Brewster
authors.affiliation: Department of Psychology, University of Victoria Victoria, BC, Canada.
authors.forename: Timothy V
authors.initials: TV
authors.lastname: Lukyn
authors.affiliation: Department of Medicine (Neurology), University of AlbertaEdmonton, AB, Canada; Neuroscience and Mental Health Institute, University of AlbertaEdmonton, AB, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Camicioli
authors.affiliation: Neuroscience and Mental Health Institute, University of AlbertaEdmonton, AB, Canada; Department of Psychology, University of AlbertaEdmonton, AB, Canada.
authors.forename: Roger A
authors.initials: RA
authors.lastname: Dixon
keywords: Victoria Longitudinal Study; cognitive change; gait; physical function; variability