Treadmill integrated robot-assisted ankle dorsiflexion training for stroke rehabilitation: A randomized controlled trial

Background: Stroke-related ankle dysfunction due to hemiparesis has a profound negative impact on gait biomechanics and walking. Task-oriented treadmill training improves gait velocity but does not lead to restitution of ankle function. Advances in robotic technology have led to the development of an adaptive ankle robot that can be integrated into treadmill walking and provide precisely timed graded assistance consistent with motor learning approaches. The aim of this study was to compare the effectiveness of a 6-week treadmill-integrated adaptive ankle robot (TMR) training to 6-weeks of treadmill training (TM) alone on improved paretic ankle motor control and gait performance. Methods: This was a single-blind (evaluator-blinded) randomized controlled trial. 45 participants received either TMR or TM training 3 times per week for 6 weeks. Primary outcomes were improved peak paretic ankle dorsiflexion (DF) angle at swing, improved DF angle at foot strike (weight acceptance), and increased gait velocity during self-selected over-ground walking. The primary analysis was based on intention-to-treat using a longitudinal regression model. An additional sub-set analysis of subjects with biomechanically defined foot drop was performed. Results: There were no significant post-training ankle dorsiflexion or gait velocity differences between groups. Six-week post-training mean peak paretic DF swing angle was (4.84 ± 6.83; 4.2 ± 6.83 p =0.63) and DF angle at foot strike was (-0.70 ± 6.55; -0.46 ± 5.70 p =0.84) respectively for TMR and TM. Gait velocity gains were similar and TMR had a mean increase of 0.54 m/s ± 0.24 and TM increased 0.56 m/s ±0.32. p =0.48 post-training. Conclusion: Integrating adaptive ankle robotics into task-specific locomotor training was not significantly better than treadmill training alone. Both interventions improved gait velocity. Promising results in ankle motor control were seen in a subset of subjects with biomechanically defined foot drop that warrants further investigation. Keywords: Stroke, hemiparetic gait, ankle robot, locomotor training Clinical trials.gov id: NCT02483676. Registered June 29, 2015, https://clinicaltrials.gov/ct2/show/NCT02483676