Background: Clinical studies in multiple sclerosis (MS) often require accurate measurement of walking distance. Utilisation of electronic devices could theoretically improve this. Mobile devices have the potential to continuously monitor health by collecting movement data. Popular fitness trackers record steps taken and distance travelled, typically using a fixed-stride length. However, applications using fixed-stride length may be less accurate in those with altered gait patterns. While useful for everyday purposes, medical monitoring requires greater accuracy.
Objective: Our aim was to determine the agreement and reliability of using a smartphone application to measure distance walked.
Method: A phone application (mSteps) was developed and tested in a pilot study and then a validation study, looking at an indoor and outdoor setting with people with multiple sclerosis (PwMS) and a control cohort.
Results: In the pilot study, the 95% limits of agreement (LOA) for outdoor tracking in control cohort lay within the a priori defined limit; however, the indoor tracking in both cohorts did not meet the defined limit. The app was then successfully validated outdoors in PwMS.
Conclusion: mSteps could be used to accurately measure distance outdoors in PwMS. There is still a need for solutions to accurately and reliably measure distance walked indoors.
Keywords: GPS tracking; Wearable technology; indoor tracking; mSteps; multiple sclerosis.