Evidence-Based Neurorehabilitation Technology
Enhancing Neurorecovery
To extend the benefits of IMT’s interactive robotic rehabilitation to the lower extremity, IMT in close collaboration with the Newman Lab for biomechanics and human rehabilitation at MIT, developed the Anklebot.
The system uses the same design principles that have made InMotion Robots the leader in upper
extremity rehabilitation.
The ankle is critical for propulsion during walking and for balance and is also important in gait for the role it plays in “shock absorption” due to foot placement, furthermore studies have shown that ankle stiffness is modulated to accommodate surface changes during locomotion.
Following stroke, “drop foot” is a common lower extremity impairment. It is caused by a weakness in the dorsiflexor muscles that lift the foot. Two major complications of drop foot are slapping of the foot after heel strike (foot slap) and dragging of the toe during swing (toe swing). In addition to inadequate dorsiflexion
(“toe-up”), the paretic ankle also suffers from excessive inversion (heel toward midline). This begins in the swing phase and results in toe contact (as opposed to heel contact) and lateral instability in stance.
In a six week clinical study utilizing the anklebot modules three times per week for one hour therapy sessions.
Subjects showed improved control of the impaired ankle , smoother movement and quicker response.
Importantly although the anklebot was used on a seated position a clinical outcome consistent with all subjects was that on average they showed a 20% improvement in walking speed.
Example of trajectory changes on 10 repetitions of a standard unassisted plantar flexion and dorsiflexion ankle targeting tasks before and after 6 weeks of performance-based ankle robot training. Note the improved consistency of responses, increased velocity (steeper slope), and smoother trajectories.
Specifications:
The Anklebot provides actuation in two of the ankle’s 3 DOF
allows 25° of dorsiflexion, 45° of plantarflexion,
25° of inversion, 20° of eversion, and 15° of internal or external rotation.
*These limits are near the maximum range of comfortable motion for healthy unimpaired individuals and beyond what is required for typical gait.
