Longitudinal measurement of physical activity using a novel automated system to explore early stage functional recovery after stroke

Introduction There is emphasis on increasing patients’ Physical Activity (PA) to reduce disability and promote independent living. Therefore a new computerised system based on real time location technology called the Rehabilitation Mobility Measurement System (RMMS) was developed to overcome limitations of the current activity monitoring methods and measure PA continuously and unobtrusively. The study objectives were to evaluate the psychometric properties of RMMS and to explore early stage functional recovery after stroke in a rehabilitation unit and at home. Methods Each participant wore a radio-frequency identification tag with an in-built motion sensor on their unaffected wrist. Walking-aids and transport equipment were also fitted with tags. All areas accessed by patients were fitted with infra-red room locators. The tags transmitted movement and location signals to a computer having customised software programs for data processing. Descriptive statistics and graphs were used for analysis. Results The RMMS was very reliable (all ICC>0.90) and demonstrated high level of agreement on validation with observational methods. Longitudinal PA was measured successfully in the rehabilitation unit for 52 patients over 64±53 days. Outside of therapy sessions, patients spent 85% of the waking day in their own rooms undertaking limited high level activities (15%).The average mobility (walking or moving around) was 15 minutes per day only and was strongly correlated with Barthel Index and modified Rivermead Index scores on discharge (spearman’s rho=.-70, p=0.00) accounting for ≥ 43% of variation in these scores. Conclusion RMMS was a reliable and valid tool for measuring mobility; a key factor influencing early stroke recovery. The small amount of time spent active strongly suggests that better organisation of time outside therapy sessions is warranted to maximise daily PA of in-patients. RMMS could be used for motivational feedback for patients and clinicians to ultimately enhance functional activity during rehabilitation in a stroke unit.