Commercially available accelerometry as an ecologically valid measure of ambulation in individuals with multiple sclerosis.

Ambulatory impairment is a prevalent consequence of multiple sclerosis (MS) that is often measured in controlled contexts using performance tests that lack ecological validity. This underscores the importance of considering alternative, ecologically valid approaches, such as commercially available accelerometers, for measuring community ambulation in individuals with MS. This consideration is warranted based on problems with existing measures of ambulation in MS (e.g., poor responsiveness and patient-clinician discordance); conceptual associations among MS pathology, impairment and gait function with relevance for the signal detected by accelerometers; assumptions that are empirically supported for the application of commercially available accelerometers as a measure of community ambulation; and evidence supporting the output of commercially available accelerometers as a measure of ambulation. Collectively, the authors believe the time is ripe for the application of commercially available accelerometers as an outcome measure of community ambulation in MS. Such an application has the potential to maximize the understanding of ambulatory impairments in real-world conditions for clinical research and practice involving individuals with MS.