title: The effect of environment and task on gait parameters after stroke: A randomized comparison of measurement conditions.
abstract: OBJECTIVE
  To assess the effect of environment and a secondary task on gait parameters in community ambulant stroke survivors and to assess the contribution of clinical symptoms to gait performance.
  
  
  METHODS
  A 2x3 randomized factorial design with 2 main factors: task (no task, motor task, cognitive task) and environment (clinic, suburban street, shopping mall).
  
  
  METHODS
  Subjects were assessed in 1 of 3 settings: 2 in the community (a suburban street and shopping mall) and 1 clinical environment.
  
  
  METHODS
  Twenty-seven people with stroke (mean age, 61+/-11.6y; mean time since stroke onset, 45.8+/-34.2mo), living at home, were recruited from community stroke groups and from a local rehabilitation unit. Selection criteria included the following: ability to give informed consent, unilateral first ever or recurrent stroke at least 6 months previously, walking independently in the community, a gait speed between 24 and 50 m/min, Mini-Mental State Examination score of 24 or higher, and no severe comorbidity.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Gait speed (in m/min), cadence, and step length were assessed by using an accelerometer with adjustable thresholds. Clinical measures hypothesized to influence gait parameters in community environments were also assessed including fatigue, anxiety and depression, and attentional deficit.
  
  
  RESULTS
  Twenty-seven people with a mean baseline gait speed of 42.2+/-5.9 m/min were randomly allocated to 1 of 9 conditions in which the setting and distraction were manipulated. Analysis of variance showed a significant main effect for environment (P = .046) but not for task (P = .37). The interaction between task and environment was not significant (P = .73). Adjusting for baseline gait speed, people walked on average 8.8m/min faster in the clinic (95% confidence interval, 0.3-17.3m/min) than in the mall. Scores for fatigue, anxiety and depression, and attentional deficit were higher than normative values but did not influence gait performance.
  
  
  CONCLUSIONS
  This study suggests that people with chronic stroke cope well with the challenges of varied environments and can maintain their gait speed while performing a secondary task. Despite moderate levels of gait impairment, gait automaticity may be restored over time to a functional level.
authors.affiliation: Department of Medicine (Rehabilitation), Wellington School of Medicine and Health Sciences, University of Otago, Wellington South, New Zealand. sue.lord@ts.co.nz
authors.forename: Susan E
authors.initials: SE
authors.lastname: Lord
authors.forename: Lynn
authors.initials: L
authors.lastname: Rochester
authors.forename: Mark
authors.initials: M
authors.lastname: Weatherall
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: McPherson
authors.forename: Harry K
authors.initials: HK
authors.lastname: McNaughton
mesh_terms: D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology; D003863:Depression / Q000503:physiopathology; D004777:Environment; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D020233:Gait Disorders, Neurologic / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology*; D020521:Stroke / Q000503:physiopathology*; D013647:Task Performance and Analysis