Effects of an ankle-foot orthosis on balance performance in patients with hemiparesis of different durations

Objective: To examine the effects of an ankle-foot orthosis (AFO) on balance performance in patients with hemiparesis of short and long duration. Design: Within-subject random order of intervention, cross-sectional study design. Settings: Medical centres and district hospitals. Subjects: Forty-two subjects with hemiparesis of short duration (< six months) and 61 subjects of long duration (> 12 months). Measurements: The balance and gait ability of subjects were evaluated both with an AFO and without. The static and dynamic balance activities were evaluated by the Balance Master System, whereas the functional balance was assessed with the Berg Balance Scale. The speed and cadence were also measured during a 10-metre walk. Paired t-test was used to determine the effect of the AFO. Results: In subjects with hemiparesis of short duration, we found that subjects wearing an AFO showed significant improvements in (1) weight-bearing distribution during quiet standing (p=0.042, 95% confidence interval (CI) 0.521, 7.325), (2) body sway during standing on foam surface with eyes open (p=0.020, 95% CI 0.020, 0.680) and eyes closed (p=0.041, 95% CI 0.023, 0.921), (3) movement velocity during limit of stability test (LOS) - toward the affected side (p=0.037, 95% CI -0.978, -0.042) and nonaffected side (p=0.008, 95% CI -2.223, -0.377), (4) maximal excursion toward the affected side (p=0.042, 95% CI -19.546, -0.071), and (5) speed (p=0.028, 95% CI -0.204, -0.017) and cadence (p=0.021, 95% CI -22.983, -1.864). Such effects were not observed in subjects with hemiparesis of long duration. Conclusions: For the subjects with hemiparesis of short duration, the AFO improves the symmetry in quiet and dynamic standing balances. It also increases speed and cadence. However, its effectiveness is minimal for patients of long duration.