Patterns of gait variability across the lifespan in persons with and without down syndrome.

BACKGROUND AND PURPOSE Greater gait variability has been observed in persons with Down syndrome (DS). An understanding of baseline patterns of variability, how these patterns relate to adaptive control of gait, and whether increasing or decreasing variability is better is necessary for physical therapists to determine whether and when to intervene. Our aim was to describe patterns of gait variability across the lifespan in persons with DS. METHODS We examined differences in patterns of gait variability in new walkers, preadolescents, and adults with DS and typical development (TD). We collected kinematic data, while participants walked on a treadmill, and analyzed the data using the nonlinear measures of Lyapunov Exponent (LyE) and Approximate Entropy (ApEn). RESULTS Beyond the greater gait variability demonstrated across the lifespan in persons with DS compared with their peers with TD, we report herein significant differences in nonlinear measures of patterns of variability. Preadolescents demonstrated higher LyE and ApEn values than new walkers and adults, suggesting that they are more adaptive in their use of variability during gait. CONCLUSION From a clinical perspective, our results suggest that it may be of value to focus interventions on increasing adaptive use of variability during gait in new walkers and adults with DS. Experience with increased variability through practice under variable conditions or with perturbations may improve adaptive use of variability during gait.