Robot-Assisted Training of Ankle Movements in Subacute Stroke Survivors


We have developed and are testing a novel ankle robot (anklebot) to enhance physical therapy for improving walking and balance functions after stroke.

  • This pilot study is designed to learn whether patients with stroke can use an ankle robot, a new investigational device, in the early period of recovery after stroke. We also want to see if using the robot to play videogames with the affected ankle will improve a patient’s control of the ankle’s movements, and their ability to walk and maintain standing balance.
  • This study will be the first to assess the potential for using the anklebot in conjunction with usual physical and occupational therapies in a rehabilitation hospital setting. Comparisons between a robotic training group and a second group receiving manual stretching and mobilization of the ankle will give us an initial idea of the effectiveness of anklebot training to accelerate restoration of functional mobility during the early subacute stroke period.
  • A new aim is to couple the robotic training with electroencephalography (EEG) to see if noninvasive recordings of brain activation patterns during ankle movements becomes modified with practice. This will help illustrate the effects of the robotic training on brain organization (“plasticity”). See Fig. 1 below.
Subject in robot group playing videogame with anklebot assistance

Figure 1
(Left) Subject in robot group playing videogame with anklebot assistance;
(Right) Control subject undergoing manual stretching.

Research Plan

We expect to enroll a total of 40 participants at UM Rehabilitation & Orthopaedic Institute, the only location where this study is being conducted.

  • Those who qualify are currently hospitalized for having a stroke, and have weakness in one leg due to the stroke.
  • The initial screening encounter will assess subjects’ abilities to independently move the affected ankle, walk, and maintain balance while standing.
    • The robot training group will receive daily 1 hour sessions to play customized video games with their weak ankle in the robot for over 200 targeted movements.
    • The stretching group will also receive over 200 daily stretching movements of their weaker ankle delivered by a trained research team member, seeking to mobilize and improve joint flexibility of the ankle.
    • Participants in both groups will be offered the opportunity to participate in an optional EEG portion of the study to record brain activity throughout robot supported activities.
  • Just prior to discharge, repeat testing of gait, balance and ankle motor control will be conducted to compare outcomes with the baseline results.

Potential Benefits

  • This research will not take away from the usual inpatient therapies; instead it will provide extra opportunities to work on lower limb impairments and function.
  • It is too early to know if either approach will make significant differences in regaining gait and balance function, but there may be some individual benefits that the research will reveal.
  • General benefits are helping to develop new robotic therapies to improve walking and balance function in future stroke survivors. Also, there is a potential benefit in indentifying patients who are most likely to be successful when using this new robotic approach to therapy during hospitalization after stroke.
  • It will not cost anything to take part in this study but participants will also not be paid to participate.
  • There is also a potential for future studies to determine if our methods can be extended into post-hospitalization outpatient physical therapy.
Subject with chronic stroke undergoing videogame-based anklebot training with concurrent EEG monitoring.

Figure 2
Subject with chronic stroke undergoing videogame-based anklebot training with concurrent EEG monitoring.

The principal investigator at UM Rehabilitation & Orthopaedic Institute Hospital for the Anklebot trial is Larry Forrester, PhD. He may be contacted directly via e-mail at or through

This page was last updated: March 27, 2015

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