title: Validity of the StepWatch Step Activity Monitor: preliminary findings for use in persons with Parkinson disease and multiple sclerosis.
abstract: BACKGROUND
  One goal for older adults with Parkinson disease (PD) and multiple sclerosis (MS) is community ambulation; however, the best way for clinicians to measure this has not been established. Self-report questionnaires rely on the participant's cognitive function and reporting accuracy, while the association between clinical timed walk tests and community ambulation may not be strong. Progress toward the identification of an appropriate clinical tool to measure strides in PD and MS populations is hampered by the lack of meaningful research and reference standards in this area.
  
  
  OBJECTIVE
  The objective of the present study was to explore the validity of the StepWatch Step Activity Monitor (SAM) in assessing stride count in persons with PD or MS. The SAM is a 2-dimensional accelerometer that counts strides and is calibrated for individual participants.
  
  
  METHODS
  A convenience sample of 20 participants completed a health history interview. Participants ambulated approximately 15 m while wearing the SAM to establish appropriate baseline calibrations, matching their stride with the device settings. Next, participants took 3 passes over the GaitMat II (GM II) while wearing the SAM. Strides counted by the GM were compared with the strides counted by the SAM.
  
  
  RESULTS
  The Pearson correlation coefficients (r) for MS and PD, respectively, were 0.99 and 1.0.
  
  
  CONCLUSIONS
  Our investigation presents preliminary data that shows the concurrent validity of the SAM when compared with the gold standard GM. The SAM appears to be a valid tool for use in persons with PD and MS. The validity was apparent in a population of widely varying impairment levels.
authors.affiliation: Mangione Physical Therapy, Warrington, PA, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Schmidt
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Pennypacker
authors.forename: Aaron H
authors.initials: AH
authors.lastname: Thrush
authors.forename: Carol I
authors.initials: CI
authors.lastname: Leiper
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Craik
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009103:Multiple Sclerosis / Q000534:rehabilitation*; D010300:Parkinson Disease / Q000534:rehabilitation*; D010414:Pennsylvania; D015203:Reproducibility of Results