title: Intraindividual Reaction Time Variability, Falls, and Gait in Old Age: A Systematic Review.
abstract: Intraindividual variability (IIV) refers to the variation in reaction time (RT) performance across a given cognitive task. As greater IIV may reflect compromise of the frontal circuitry implicated in falls and gait impairment in older adults, we conducted a systematic review of the literature relating to this issue.
  
  
  
  Searches were conducted of electronic databases that identified empirical investigations of IIV, falls, and gait in older adult samples with a mean age of 65 years or older. Data were extracted relating to IIV measures, study population, and outcomes.
  
  
  
  Of 433 studies initially identified, 9 met inclusion criteria for IIV and falls (n = 5), and gait (n = 4). Representing a total of 2,810 older participants, all of the studies of IIV and falls showed that elevated variability was associated with increased risk of falling, and half of the studies of gait indicated greater IIV was related to gait impairment.
  
  
  
  Across studies, IIV measures were consistently associated with falls in older persons and demonstrated some potential in relation to gait. IIV metrics may, therefore, have considerable potential in clinical contexts and supplement existing test batteries in the assessment of falls risk and gait impairment in older populations.
authors.affiliation: School of Psychology, University of Leeds, Leeds, UK.
authors.forename: Jack
authors.initials: J
authors.lastname: Graveson
authors.affiliation: School of Psychology, University of Leeds, Leeds, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Bauermeister
authors.affiliation: School of Psychology, University of Leeds, Leeds, UK.
authors.forename: Denis
authors.initials: D
authors.lastname: McKeown
authors.affiliation: School of Psychology, University of Leeds, Leeds, UK. d.bunce@leeds.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Bunce
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D011930:Reaction Time / Q000502:physiology*
keywords: Cognition; Developmental change; Falls; Life course; Mobility problems