Purpose: To determine validity, reliability and feasibility of accelerometers (ActivPAL™, Sensewear Pro2 Armband) and portable global positioning systems (GPS) (Garmin Forerunner 405CX) for community ambulation measurement after stroke. Methods: Fifteen community-dwelling stroke survivors attended two sessions; completing a 6-minute walk, treadmill walking, and 200-m outdoor circuit. Feasibility was determined by wearing devices over four days. Measures collected included step count, time spent walking, distance, energy expenditure and location. Intra-class correlation coefficients (ICC), Bland-Altman plots and absolute percentage of error (APE) were used to determine validity and reliability. Results: ActivPAL™ had excellent validity and reliability for most measures (ICC: 0.821-0.999, APE: 0%-11.1%), except for good-excellent findings at speeds < 0.42 m/s (ICC: 0.659-0.894, APE: 1.6%-11.1%). Sensewear had missing values for 23% of recordings and high error for all measures. GPS demonstrated excellent validity and reliability for time spent walking and step count (ICC: 0.805-0.999, APE: 0.9%-10%), and 100% accuracy for location. However, it was not valid or reliable for distance (ICC = -0.139, APE = 23.8%). All devices appeared feasible for community ambulation measurement with assistance for setup and data analysis. Conclusions: ActivPAL™ and Garmin GPS appear valid, reliable and feasible tools for community ambulation measurement after stroke, except for distance. Sensewear demonstrated poor validity and reliability when worn on the paretic arm.
Mahendran, N., Kuys, S. S., Downie, E., Ng, P., & Brauer, S. G. (2016). Are Accelerometers and GPS Devices Valid, Reliable and Feasible Tools for Measurement of Community Ambulation after Stroke? Brain Impairment, 17(2), 151–161. https://doi.org/10.1017/BrImp.2016.13