Objective physical activity measurement in people with multiple sclerosis: a review of the literature

Purpose: The purpose of this study is to identify the objective physical activity (PA) measurement tools and outputs that are used within Multiple Sclerosis (MS) literature. Methods: A systematic search strategy on eight databases (2000–2016) using keywords associated with MS and PA. Results: This review includes 32 papers. Uni-axial accelerometers were the most popular objective PA tool in this review (68%). Pedometers (14%) and multi-sensor systems (3%) were the second and third most common. PA outputs included activity counts per day, steps per day, energy expenditure per day, minutes of moderate-vigorous PA (MVPA), minutes of light PA and daily dynamic activity. Both activity counts per day (n = 21 studies), and steps per day (n = 11 studies) were most commonly used representing 78%. Conclusion: Uni-axial accelerometers and pedometers are the most popular PA measurement tools used in MS literature. However, developments in the field mean that most new sensors are tri-axial, and multi-sensor systems are also available. Researchers should use devices with published validation information, and should utilize the detail on activity patterns available from accelerometer measurement instead of expressing a single unit such as activity counts or step counts per day. Attention to capturing the duration, frequency, intensity and energy expended during daily PA is warranted. Implications for Rehabilitation The review reports that accelerometers were the research tool most frequently reported in the literature, though there were differences in device type and in how activity data was extracted from the stored information. The majority of research studies of physical activity levels in Multiple Sclerosis fail to provide an adequate range of activity outcomes, frequently using outcomes which do not allow simple cross-comparisons with other populations.