title: Age-dependent differences in the attentional demands of obstacle negotiation.
abstract: BACKGROUND
  Although the attention directed to gait does increase as an impending obstacle nears, it remains unclear whether the allocation of attentional resources differs between the precrossing phase of obstacle negotiation and the crossing phase of this task. This study compared the attentional demands associated with steady-state walking and the precrossing and crossing phases of an obstacle-negotiation task between young and older adults.
  
  
  METHODS
  Fifteen younger and 15 older adults participated in this study. Participants were required to perform a verbal reaction time task during three events: (1) steady-state unobstructed gait, (2) precrossing (the final full stride prior to obstacle crossing), and (3) obstacle crossing.
  
  
  RESULTS
  The attention directed during precrossing exceeds that of steady-state walking for both younger and older adults. Younger adults direct more attention to gait during precrossing than they do during crossing. However, precrossing is equally attentionally demanding as crossing for older adults, and both of these events require more attention than does steady-state gait in this age group.
  
  
  CONCLUSIONS
  The task of obstacle negotiation, from precrossing through obstacle crossing, is attentionally demanding for elderly persons, and fall risk, due to a compromised availability of attentional resources, does occur prior to obstacle crossing in this age group.
authors.affiliation: Department of Kinesiology, University of Lethbridge, Lethbridge, AB Canada, T1K 3M4. l.brown@uleth.ca
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Brown
authors.forename: Nicole C
authors.initials: NC
authors.lastname: McKenzie
authors.forename: Jon B
authors.initials: JB
authors.lastname: Doan
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000523:psychology; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D016138:Walking / Q000523:psychology*