Polio survivors have poorer walking adaptability than healthy individuals

Falling is a major health problem in polio survivors, often occurring as a result of tripping, slipping or misplaced steps. Therefore, reduced walking adaptability possibly plays an important role.

Does walking adaptability, assessed on an interactive treadmill, differ between polio survivors and healthy individuals?

In this cross-sectional study, 48 polio survivors with at least one reported fall in the past year and/or fear of falling and 25 healthy individuals of similar age walked at self-selected comfortable fixed speed on an instrumented treadmill. Walking adaptability was measured as i) target-stepping accuracy (determined as variable error [VE] in mm independent of speed) in three conditions; 0 %, 20 % and 30 % variation in step length and width, and ii) anticipatory and reactive obstacle avoidance (ObA and ObR, in percentage successfully avoided). All trials were checked for valid step detection.

46 polio survivors (mean ± SD age: 63.2 ± 8.7 years) and 25 healthy individuals (64.3 ± 6.6 years, p = 0.585) showed valid step detection. Compared to healthy individuals (mean±SE VE: 30.6±1.2 mm), polio survivors stepped less accurately onto targets (36.4±0.9 mm, p = 0.001), especially with their least-affected leg. Polio survivors avoided fewer obstacles successfully (mean±SE ObA: 83±3 %, ObR: 59±4 %) than healthy individuals (100±0.3 %, p < 0.001 and 94±3 %, p < 0.001, respectively), with a stronger decline in success rates from anticipatory to reactive obstacle avoidance for polio survivors (p < 0.001).

Polio survivors reporting falls and/or fear of falling had a demonstrably reduced walking adaptability, especially so for reactive obstacle avoidance, which requires step adjustments under high time-pressure demands. Future research should study the merit of walking-adaptability assessment to currently used clinical methods of fall-risk assessment within this population.