Test--retest reliability of the StepWatch Activity Monitor outputs in individuals with chronic stroke

Clin Rehabil. Oct-Nov 2008;22(10-11):871-7. doi: 10.1177/0269215508092822.

Abstract

Objective: To examine the test-retest reliability of the StepWatch Activity Monitor outputs over two periods, a week apart, in participants with stroke.

Design: Test-retest reliability study over monitoring periods of one, two and three days.

Setting: Participant's usual environment.

Participants: Forty participants more than six months post stroke.

Main measures: StepWatch outputs: total step count, number of steps at high medium and low stepping rates, sustained activity indices, peak activity index.

Results: The intraclass correlation coefficients were high for all StepWatch outputs and all monitoring periods but were highest for the three-day monitoring period (0.930-0.989) and lowest for the one-day monitoring period (0.830-0.950). The coefficient of variation ranged from 6.7% to 48.7% over the monitoring periods, with higher variation shown for shorter monitoring periods. The most reliable four outputs had 95% limits of agreement between three-day periods that were less than 40%. These were total step count (+/-37.8%), highest step rate in 1 minute (+/-23.0%), highest step rate in 5 minutes (+/-38.6%) and peak activity index (+/-29.8%). The highest step rate in 1 minute was the only StepWatch output that had 95% limits of agreement less than 40% for the two-day (+/-31.2%) and one-day (+/-36.7%) monitoring periods.

Conclusions: Total step count, highest step rate in 1 minute, highest step rate in 5 minutes and peak activity index have good test-retest reliability over a three-day monitoring period, with lower reliability shown by the other StepWatch outputs. In general, monitoring over one or two days is less reliable.

Publication types

  • Evaluation Study

MeSH terms

  • Activities of Daily Living
  • Aged
  • Chronic Disease / rehabilitation*
  • Disability Evaluation
  • Female
  • Humans
  • Male
  • Middle Aged
  • Monitoring, Ambulatory / instrumentation*
  • Monitoring, Ambulatory / methods
  • Motor Activity
  • Recovery of Function
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Stroke Rehabilitation*
  • Time Factors
  • Walking / statistics & numerical data*