Mobility beyond the clinic: the effect of environment on gait and its measurement in community-ambulant stroke survivors

Objective: To explore the impact of a complex community environment on gait parameters (speed, step length and cadence) for community-dwelling participants with a previous stroke, and compare outcome measures commonly used in a clinical environment. Design: Repeated measurement of participants in different environments. Setting: One clinic and two community environments (suburban street and shopping mall). Subjects: Thirty community-dwelling stroke participants with chronic stroke who were classified according to gait speed (20-50 m/min on 10-metre timed walk) as marginal community walkers. Outcome measures: During a six-minute walk test (6MWT) a step activity monitor (SAM) and odometer were used to calculate gait speed, step length and cadence. The 10-metre timed walk (10MTW) was measured in a clinic environment. Analysis: A mixed linear model examined differences in gait measurements in the different environments. Bland-Altman analysis illustrated agreement between gait speed measures (6MWT and 10MTW). Results: A statistically significant, but not a clinically significant difference in gait speed between some environments was found. Gait speed was slowest in the mall and fastest in the street with a difference of only 2.1 m/min between these environments (95% confidence interval (CI) -3.8 to -0.5, P<0.01). Comparison of clinic 10MTW and street 6MWT showed wide limits of agreement (-18.5 to 16.9 m/min) which improved for clinic 6MWT and street 6MWT comparisons (-5.7 to 8.9 m/min). Conclusion: Despite residual gait deficit, the gait parameters of these chronic stroke survivors did not deteriorate markedly under challenging conditions. The 6MWT is recommended as a clinical measure for community ambulation.