Initial assessment of the StepWatch Activity Monitor™ to measure walking activity in Rett syndrome

Abstract

Purpose: In girls and women with Rett syndrome, we assessed the accuracy of the StepWatch Activity Monitor™ and investigated relationships between daily step counts, gross motor skills and age. Method: Twelve subjects (age 12.9 ± 8.0 years) participating in the Australian Rett Syndrome Database wore a StepWatch during a videoed session of activities to assess agreement with the criterion method of observation. Physical activity data were also collected over the course of 6 ± 1 whole days. Relationships between agreement, gross motor skills, average daily step count and age were analyzed. Results: The number of steps obtained using the StepWatch was similar to that viewed on video (mean difference = 0 steps per minute) and agreement did not differ with the level of general (p = 0.389) or complex gross motor skills (p = 0.221). Subjects were less active than their healthy peers (difference 6086 steps per day; p = 0.001), and physical activity was significantly greater in those who were younger and with greater levels of motor skill. Conclusions: The StepWatch provided accurate information on the physical activity of girls and women with Rett syndrome regardless of their level of gross motor function. Physical activity reduced with age despite the ability to walk. Advocacy for pro-active lifestyles is justified.