Objective monitoring of physical activity behavior in multiple sclerosis.

Background: There has been an increased interest by researchers and clinicians in the study of physical activity behavior and its determinants and consequences in persons with multiple sclerosis (MS). Objective: This paper provides an overview of the objective monitoring of physical activity in persons with MS using motion sensors such as pedometers and accelerometers. Major findings: Accumulating evidence supports the reliability and validity of pedometers, particularly the Yamax SW-200, as a measure of physical activity in fully ambulatory and ambulatory impaired persons with MS. There is some degree of inaccuracy with the Yamax SW-200 pedometer during self-selected and slow walking speeds. By comparison, substantial evidence from multiple approaches, across a range of researchers, and with different units/manufacturers supports the validity of accelerometers as a measure of physical activity in fully ambulatory and ambulatory impaired persons with MS. There is no concern regarding the inaccuracy of accelerometers for measuring steps taken during slow walking. Conclusion: Researchers and clinicians now have a better set of motion sensors that provide objective, valid, and reliable measures of physical activity in persons with MS. This should support an expanding interest and study of physical activity and its determinants and consequences in MS as well as monitoring physical activity and its change in clinical practice. Importantly, there is a major concern with the application of motion sensors as a pure measure of physical activity in persons with MS, and researchers and clinicians should be aware of this conundrum in any application of accelerometers. [ABSTRACT FROM AUTHOR]