PURPOSE: The objective of this study was to investigate the relationship between medio-lateral foot placement characteristics and environmental context when individuals with Multiple Sclerosis (MS) walk with a rollator (four-wheeled walker). METHOD: Ten women diagnosed with MS, who used rollators regularly, participated in this study. First, a rollator-based technique of calculating step width (SW) was validated in this patient population by comparing the output of an instrumented rollator (iWalker) to a laboratory-based Vicon Motion Capture System. Secondly, the iWalker-based technique was used to calculate the participants' SW and SW variability as they used the iWalker in four common outdoor community environments. RESULTS: There was a strong level of agreement between the iWalker and Vicon SW calculations, with an intra-class correlation coefficient of 0.993 and a root-mean-square difference of 0.71 cm. Furthermore, SW variability (P = 0.002), but not SW (P = 0.288), was influenced by the walking environment (i.e. between the in-lab vs. up-ramp and up-ramp vs. down-ramp conditions). CONCLUSIONS: Foot placement variability appears to be influenced by the walking environment of MS patients. Therefore, an enhanced understanding of walker-user interactions in relation to the environment must be established in order to improve mobility.
PURPOSE: The objective of this study was to investigate the relationship between medio-lateral foot placement characteristics and environmental context when individuals with Multiple Sclerosis (MS) walk with a rollator (four-wheeled walker). METHOD: Ten women diagnosed with MS, who used rollators regularly, participated in this study. First, a rollator-based technique of calculating step width (SW) was validated in this patient population by comparing the output of an instrumented rollator (iWalker) to a laboratory-based Vicon Motion Capture System. Secondly, the iWalker-based technique was used to calculate the participants' SW and SW variability as they used the iWalker in four common outdoor community environments. RESULTS: There was a strong level of agreement between the iWalker and Vicon SW calculations, with an intra-class correlation coefficient of 0.993 and a root-mean-square difference of 0.71 cm. Furthermore, SW variability (P = 0.002), but not SW (P = 0.288), was influenced by the walking environment (i.e. between the in-lab vs. up-ramp and up-ramp vs. down-ramp conditions). CONCLUSIONS: Foot placement variability appears to be influenced by the walking environment of MS patients. Therefore, an enhanced understanding of walker-user interactions in relation to the environment must be established in order to improve mobility.