title: Comparison of pedometer and accelerometer derived steps in older individuals with Parkinson's disease or osteoporosis under free-living conditions.
abstract: OBJECTIVE
  To compare self-reported pedometer steps with accelerometer steps under free-living conditions in individuals with Parkinson's disease (PD) or osteoporosis (OP).
  
  
  METHODS
  Seventy-three individuals with PD and 71 individuals with OP wore a pedometer (Yamax LS2000) and an accelerometer (ActiGraph GT1M/GT3X+) simultaneously for one week.
  
  
  RESULTS
  Fifty-one individuals with PD (72.6 ± 5.3 years) and 61 with OP (75.6 ± 5.3 years) provided simultaneously recorded data for 3-7 consecutive days. Pedometer steps were significantly lower than accelerometer steps in the PD group (p = .002) but not in the OP group (p = .956). Bland-Altman plots demonstrated wide limits of agreement between the instruments in both PD (range = 6,911 steps) and OP (range = 6,794 steps).
  
  
  CONCLUSIONS
  These results suggest that the ActiGraph GT1M/GT3X+ should be preferred over the Yamax LS2000 for the assessment of steps in both research and clinical evaluations, particularly in individuals with PD or altered gait.
authors.affiliation: Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Huddinge, Sweden.
authors.forename: Martin Benka
authors.initials: MB
authors.lastname: Wallén
authors.forename: Ing-Mari
authors.initials: IM
authors.lastname: Dohrn
authors.forename: Agneta
authors.initials: A
authors.lastname: Ståhle
authors.forename: Erika
authors.initials: E
authors.lastname: Franzén
authors.forename: Maria
authors.initials: M
authors.lastname: Hagströmer
mesh_terms: D061725:Accelerometry / Q000295:instrumentation / Q000379:methods; D000368:Aged; D003720:Densitometry / Q000379:methods; D019719:Diagnostic Equipment; D005260:Female; D006801:Humans; D057187:Independent Living; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009068:Movement / Q000502:physiology; D010024:Osteoporosis / Q000175:diagnosis / Q000503:physiopathology; D010300:Parkinson Disease / Q000175:diagnosis / Q000503:physiopathology; D004856:Postural Balance / Q000502:physiology; D015203:Reproducibility of Results