Modular Ankle Robotics Training in Early Subacute Stroke: A Randomized Controlled Pilot Study

Background. Modular lower extremity robotics may offer a valuable avenue for restoring neuromotor control after hemiparetic stroke. Prior studies show that visually guided and visually evoked practice with an ankle robot (anklebot) improves paretic ankle motor control that translates into improved overground walking. Objective. To assess the feasibility and efficacy of daily anklebot training during early subacute hospitalization poststroke. Methods. Thirty-four inpatients from a stroke unit were randomly assigned to anklebot (n = 18) or passive manual stretching (n = 16) treatments. All suffered a first stroke with residual hemiparesis (ankle manual muscle test grade 1/5 to 4/5), and at least trace muscle activation in plantar-or dorsiflexion. Anklebot training employed an assist-as-needed approach during >200 volitional targeted paretic ankle movements, with difficulty adjusted to active range of motion and success rate. Stretching included >200 daily mobilizations in these same ranges. All sessions lasted 1 hour and assessments were not blinded. Results. Both groups walked faster at discharge; however, the robot group improved more in percentage change of temporal symmetry (P =.032) and also of step length symmetry (P =.038), with longer nonparetic step lengths in the robot (133%) versus stretching (31%) groups. Paretic ankle control improved in the robot group, with increased peak (P <= .001) and mean (P <= .01) angular speeds, and increased movement smoothness (P <= .01). There were no adverse events. Conclusion. Though limited by small sample size and restricted entry criteria, our findings suggest that modular lower extremity robotics during early subacute hospitalization is well tolerated and improves ankle motor control and gait patterning.