Predictors of changes in gait performance over four years in persons with late effects of polio.

BACKGROUND

Reduced gait performance is common in persons with late effects of polio.

OBJECTIVE

To identify predictors of change in gait performance over four years in persons with late effects of polio.

METHODS

Gait performance was assessed annually in 51 ambulatory persons (mean age 64 years, SD 6) by the Timed "Up & Go" (TUG), Comfortable and Fast Gait Speed (CGS, FGS), and 6-Minute Walk Test (6MWT). Isokinetic knee extensor and flexor muscle strength was measured with a Biodex dynamometer. Mixed Linear Models were used to analyze changes in gait performance and to identify any predictors of change among the covariates gender, age, body mass index, time with new symptoms, baseline reduction in gait performance and knee muscle strength.

RESULTS

There were significant linear effects over time (reduction per year) for three gait performance tests; CGS (0.8%; p < 0.05), FGS (1.7%; p < 0.001), and 6MWT (0.7%; p < 0.05) with significant random effects for all tests. The strongest predictor of a change in gait performance was the individual variations in the knee flexor strength (p < 0.001).

CONCLUSION

The small gradual reduction in gait performance over time in persons with late effects of polio is primarily determined by the individual variations in the knee flexor strength.