title: Longitudinal Relationships Between Cognitive Decline and Gait Slowing: The Tasmanian Study of Cognition and Gait.
abstract: BACKGROUND
  Gait slowing and cognitive decline are both common in older people. Although cross-sectionally related, the longitudinal associations between specific cognitive functions and gait speed are less well understood. We aimed to determine whether decline in specific cognitive domains are associated with change in gait speed.
  
  
  METHODS
  Participants aged 60-85, randomly selected from the electoral roll, were assessed twice over 3 years. Gait speed was obtained using the GAITRite walkway. Raw scores from a cognitive battery were subjected to principal component analyses deriving summary domains of executive function, processing speed, memory, and visuospatial ability. Multivariable linear regression was used to examine the associations between change in each cognitive domain and change in gait speed, adjusting for covariates and stratifying for the presence of baseline cognitive impairment.
  
  
  RESULTS
  Mean age at baseline was 71.1 years (SD = 6.7) and 56% (159/284) were men. Mean follow-up was 2.55 (0.47) years. Decline in executive function, but not other cognitive domains (p > .05), was associated with decline in gait speed, cm/s (β = -3.55, 95% CI = -5.49, -1.61; p < .001), both in the presence and absence of baseline cognitive impairment. Stronger associations were seen for those with baseline multiple domain cognitive impairment (β = -6.38, 95% CI = -12.49, -0.27) and nonamnestic single-domain cognitive impairment (β = -7.74, 95% CI = -14.76, -0.72).
  
  
  CONCLUSIONS
  Decline in nonamnestic function (specifically executive function) was associated with decline in gait speed irrespective of the presence of baseline cognitive impairment. Strategies to improve or maintain executive function may prevent gait slowing.
authors.affiliation: Stroke and Aging Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia. Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia. michele.callisaya@monash.edu.
authors.forename: Michele L
authors.initials: ML
authors.lastname: Callisaya
authors.affiliation: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Blizzard
authors.affiliation: Stroke and Aging Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia. School of Psychology, University of Birmingham, Edgbaston, UK.
authors.forename: Amanda G
authors.initials: AG
authors.lastname: Wood
authors.affiliation: Stroke and Aging Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia. Florey Neuroscience Institutes, Heidelberg, Victoria, Australia.
authors.forename: Amanda G
authors.initials: AG
authors.lastname: Thrift
authors.affiliation: Melbourne Neuropsychology Services, East Melbourne, Victoria, Australia.
authors.forename: Tracey
authors.initials: T
authors.lastname: Wardill
authors.affiliation: Stroke and Aging Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia. Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia.
authors.forename: Velandai K
authors.initials: VK
authors.lastname: Srikanth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D056344:Executive Function / Q000502:physiology; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009483:Neuropsychological Tests; D013648:Tasmania
keywords: Aging; Brain; Cognition; Executive function; Gait; Memory