The effect of shoe lifts on static and dynamic postural control in individuals with hemiparesis

Objective: To determine the effect of lifts to the shoe of the nonaffected leg on weight symmetry and dynamic posturography in individuals with hemiparesis. Design: Quantitative posturography was performed to determine subjects' response to sudden perturbations; Subjects received graded forward and backward perturbations while standing on a movable force platform. Compelled shift of the body weight was induced with sized lifts to the shoe of the nonaffected leg. Balance responses were analyzed in terms of latency and strength of neuromuscular response. Symmetry scores were used to characterize the symmetry of stance. Setting: Free-standing acute inpatient rehabilitation hospital. Participants: Ten individuals with hemiparesis as a result of unilateral stroke. Main Outcome Measures: Weight symmetry scores, latencies of each leg's active response to the support surface translations, and response strength scores of each leg to the platform translations. Results: When no lift was used, weight symmetry was characterized by underloading of the affected limb, as well as by longer onset latencies for the affected limb compared with the stronger one (158.5 +/- 3.9 vs 151.1 +/- 3.5ms; p < .01 for large backward translations; 165.7 +/- 7.2 vs 158.0 +/- 5.1ms; p < .01 for large forward translations). Response strength of the nonparetic limb was 2 times greater than the response strength of the weaker extremity (p < .05). Compelled weight shift induced by lifts applied to the shoe of the nonparetic limb promoted improved weight symmetry, shortened latencies, and increased magnitudes of the response strength. Conclusion: Lifts applied to the shoe of the stronger limb induced a body weight shift toward the paretic limb and resulted in improved symmetry of stance and postural control of individuals with hemiparesis. We suggest that compelled weight distribution induced by lifts to the shoe of the stronger limb could help treat ambulatory individuals with asymmetric stance and hemiparesis caused by unilateral stroke.