Original articleCriterion Validity of the StepWatch Activity Monitor as a Measure of Walking Activity in Patients After Stroke
Section snippets
Participants
A convenience sample of 25 patients with chronic stroke was recruited from the hospital stroke service and local newspaper advertising. This sample size was chosen to provide sufficient numbers for analysis based on previous sample sizes of between 10 and 16 in similar validation studies.11, 15 Participants were eligible for inclusion if they were at least 6 months poststroke, were aged between 30 and 80, had not had more than 2 falls in the previous 6 months, and had not had any lower-limb
Results
Twenty-five participants with a median age of 69 years (range, 42–79y) were enrolled in the study. There were 17 men and 8 women. Ten participants had right-sided paresis. The median score on the PF index of the SF-36 was 19 (range, 11–29). The median gait speed was 0.5m/s (range, 0.1–0.9m/s). All participants walked independently with a median score on the RMI of 14 (range, 10–15). Twenty-two participants reported independent walking outside over pavements (RMI item 9), and 20 participants
Discussion
In this study, we show that the SAM has good criterion validity for adults with stroke compared with 3-DGA and footswitches. This extends previous work with handheld counters.15 Our study also extends previous work by using different environments and conditions, which we selected for their relevance to community mobility.26 Therefore, a range of commonly encountered outdoor terrains was included such as uneven surfaces, concrete, grass, inclines, declines, and stairs. Because the SAM is
Conclusions
This study has shown that the SAM has criterion validity when used on the nonparetic limb to measure steps in both clinical and natural environments. However, more errors are apparent when the SAM is worn on the paretic limb while walking over a variety of terrains. Validation is recommended before the use of the SAM in patients with neurologic conditions affecting bilateral legs because there may be more error, particularly in outdoor environments.
Acknowledgments
We gratefully acknowledge the contributions of Pat Bennett and Alan Barber, MD, PhD, of the Auckland District Health Board for subject recruitment.
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Cited by (0)
Supported by a Health Research Council Clinical Training Fellowship (grant no. 06/059).
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.