title: Reliability and minimal detectable change of gait variables in community-dwelling and hospitalized older fallers.
abstract: OBJECTIVE
  Gait variables may constitute surrogate outcomes for fall risk. Their reliability in a specific population of older fallers has not been fully established, which limits their research and clinical applications. This study aimed to determine test-retest reliability and minimal detectable change (MDC) values for selected fall-related gait variables in older adults with a recent fall history.
  
  
  METHODS
  Community-dwelling (n=30) and hospitalized (n=30) fallers aged≥65 years were assessed twice using an instrumented pressure-sensitive walkway, under single- and dual-task gait conditions. Intraclass correlation coefficient (ICC(2,1)), standard error of measurement (SEM; SEM%) and MDC at 95% confidence level (MDC95; MDC95%), were used as reliability estimates.
  
  
  RESULTS
  The ICC(2,1) for gait velocity was greater than 0.84 across all gait conditions and groups; SEM% and MDC95% did not exceed 6.5% and 18.1%, respectively. Gait variability measures returned lower ICC(2,1) (range 0.18-0.79), and markedly higher SEM% (16.3-31.9%) and MDC95% (45.3-88.3%). Overall, hospitalized fallers exhibited larger SEM and MDC95 values for variability measures compared to community-dwellers in all gait conditions, while larger values were found for all variables while dual-tasking compared to single-tasking in both groups.
  
  
  CONCLUSIONS
  Gait velocity was found to be highly reliable and likely to be sensitive to change over repeated sessions in community-dwelling and hospitalized older fallers, both under single- and dual-task conditions. Gait variability measures showed lower reliability, irrespective of gait condition or group, displaying consistently larger measurement error, particularly under dual-task conditions. Clinicians should consider MDC95 values before using gait variability variables as evaluative outcome measures at patient level.
authors.affiliation: Division of Bone Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland. Electronic address: melany.hars@hcuge.ch.
authors.forename: Mélany
authors.initials: M
authors.lastname: Hars
authors.forename: François R
authors.initials: FR
authors.lastname: Herrmann
authors.forename: Andrea
authors.initials: A
authors.lastname: Trombetti
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005684:Gait / Q000502:physiology*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D057187:Independent Living / Q000706:statistics & numerical data; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000706:statistics & numerical data*
keywords: Aged; Dual-task; Falls; Gait; Reliability