title: Age-associated effects of a concurrent cognitive task on gait speed and stability during narrow-base walking.
abstract: BACKGROUND
  In older adults, changes in speed and stability during walking are associated with impaired balance and increased fall risk. Narrow-base walking requires increased frontal plane stability and can be used to assess postural control while walking. Performance of a concurrent cognitive task (dual task) may further increase the complexity of walking, potentially allowing identification of individuals with instability that is not detected under single-task conditions. The purpose of this study was to examine age-associated effects of a cognitive task on speed and frontal plane stability during narrow-base walking.
  
  
  METHODS
  Thirty-four healthy adults participated, categorized by age: <65, 65-74, and > or =75 years. Participants walked at a comfortable pace within a narrow path under both single- and dual-task conditions. We examined spatiotemporal variables and frontal plane center of mass (CoM) parameters using a 13-segment biomechanical model.
  
  
  RESULTS
  Increasing age (p <.001) and the performance of a concurrent cognitive task (p <.001) were both associated with decreased speed, with no interaction between these factors. Frontal plane CoM displacement and velocity increased with increasing age (both p <.001), but dual-task performance had no effect on these variables (both p >.450).
  
  
  CONCLUSIONS
  Age-associated changes in both speed and stability are observed during narrow-base walking. Among this sample of healthy older adults, the addition of a concurrent cognitive task resulted in reduced speed, with no effect on frontal plane stability. Further research is needed to determine if dual-task, narrow-base walking is a sensitive and specific approach to identifying older adults at risk for falls.
authors.affiliation: Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195-6490, USA. vekelly@u.washington.edu
authors.forename: Valerie E
authors.initials: VE
authors.lastname: Kelly
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Schrager
authors.forename: Robert
authors.initials: R
authors.lastname: Price
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: Anne
authors.initials: A
authors.lastname: Shumway-Cook
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D016138:Walking / Q000502:physiology*