Immediate effect of gait training using the hybrid assistive limb in patients in the acute phase of stroke: a prospective pilot study

Abstract

The effectiveness of Hybrid Assistive Limb (HAL) gait training in patients in the acute phase of stroke remains unclear. We prospectively assessed the immediate effects of HAL gait training in this patient population. In this prospective pilot study, four patients with acute-phase stroke undergoing HAL gait training were included. The 10-meter walking test (10MWT) at maximum speed was conducted immediately before and after HAL or conventional gait training sessions. Step length, velocity, and cadence during the 10MWT and their changes from before to after training were evaluated. Differences in these changes between HAL and conventional gait training were analyzed after adjustment for patient-specific differences, the corresponding pre-training value, and days from the first gait-training session. Correlations between pre-training values and rates of change were also analyzed. In an exploratory subgroup analysis, sessions were categorized according to pre-training velocity as slower (S; ≤0.4 m/s) or faster (F; >0.4 m/s). Rates of changes in gait parameters were compared between HAL and conventional training across all units and within each group. After adjustment, no significant differences in gait parameter changes were observed between HAL and conventional gait training. The adjusted between-condition differences (HAL − conventional) were 0.033 m/s for velocity (95% confidence interval [CI], −0.004 to 0.071; p  = 0.0775), 1.60 cm for step length (95% CI, −0.05 to 3.25; p  = 0.0564), and 2.02 steps/min for cadence (95% CI, −2.10 to 6.14; p  = 0.3278). Immediately after HAL training, step length ( p  < 0.0001) and velocity ( p  = 0.0169) increased significantly, whereas cadence remained unchanged ( p  = 0.5848). No significant changes were observed after conventional training. Pre-training cadence negatively correlated with its rate of change after HAL training. In the exploratory S-group analysis, rates of change in step length, velocity, and cadence were higher after HAL than after conventional training ( p  = 0.0103, 0.0057, and 0.0261, respectively). Although the adjusted analysis showed no significant differences between HAL and conventional gait training, HAL training was associated with immediate improvements in step length and walking velocity in the within-condition analysis. Exploratory findings suggest that patients with slower walking velocity may show a greater immediate response to HAL gait training. Further studies are warranted to confirm these findings.