Modular lower extremity (LE) 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.

Assess the feasibility and efficacy of daily anklebot training during early sub-acute hospitalization post-stroke.

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.

Both groups walked faster at discharge, however the robot group improved more in percent change of temporal symmetry (p=0.032) and also of step length symmetry (p=0.038), with longer nonparetic step lengths in the robot (133%) vs. stretching (31%) groups. Paretic ankle control improved in the robot group, with increased peak (p≤ 0.001) and mean (p≤ 0.01) angular speeds, and increased movement smoothness (p≤ 0.01). There were no adverse events.

Though limited by small sample size and restricted entry criteria, our findings suggest that modular lower extremity robotics during early sub-acute hospitalization is well tolerated and improves ankle motor control and gait patterning.