title: The reliability of postural balance measures in single and dual tasking in elderly fallers and non-fallers.
abstract: BACKGROUND
  The purpose of this study was to determine the reliability of a forceplate postural balance protocol in a group of elderly fallers and non-fallers. The measurements were tested in single and dual-task conditions, with and without vision.
  
  
  METHODS
  37 elderly (mean age 73 +/- 6 years) community-dwellers were included in this study. All were tested in a single (two-legged stance) and in a dual-task (two-legged stance while counting backwards aloud in steps of 7's) condition, with and without vision. A forceplate was used for registering postural variables: the maximal and the root-mean-square amplitude in medio-lateral (Max-ML, RMS-ML) and antero-posterior (Max-AP, RMS-AP) direction, mean velocity (MV), and the area of the 95% confidence ellipse (AoE). Reliability of the test protocol was expressed with intraclass correlation coefficients (ICC), with 95% limits of agreement (LoA), and with the smallest detectable difference (SDD).
  
  
  RESULTS
  The ICCs for inter-rater reliability and test-retest reliability of the balance variables were r = 0.70-0.89. For the variables Max-AP and RMS-AP the ICCs were r = 0.52-0.74. The SDD values were for variable Max-ML and Max-AP between 0.37 cm and 0.83 cm, for MV between 0.48 cm/s and 1.2 cm/s and for AoE between 1.48 cm2 and 3.75 cm2. The LoA analysis by Bland-Altman plots showed no systematic differences between test-retest measurements.
  
  
  CONCLUSIONS
  The study showed good reliability results for group assessment and no systematic errors of the measurement protocol in measuring postural balance in the elderly in a single-task and dual-task condition.
authors.affiliation: Department of Rheumatology and Institute of Physical Medicine, University Hospital Zurich, Zurich, Switzerland. Jaap.Swanenburg@usz.ch
authors.forename: Jaap
authors.initials: J
authors.lastname: Swanenburg
authors.forename: Eling D
authors.initials: ED
authors.lastname: de Bruin
authors.forename: Kathrin
authors.initials: K
authors.lastname: Favero
authors.forename: Daniel
authors.initials: D
authors.lastname: Uebelhart
authors.forename: Theo
authors.initials: T
authors.lastname: Mulder
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control* / Q000706:statistics & numerical data; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000886:Anthropometry / Q000379:methods; D003072:Cognition Disorders / Q000175:diagnosis; D015331:Cohort Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination / Q000379:methods; D009483:Neuropsychological Tests / Q000592:standards; D015588:Observer Variation; D004856:Postural Balance / Q000502:physiology*; D011237:Predictive Value of Tests; D011596:Psychomotor Disorders / Q000175:diagnosis; D020886:Somatosensory Disorders / Q000175:diagnosis* / Q000503:physiopathology; D015837:Vestibular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D014724:Vestibular Function Tests / Q000379:methods