Physical therapists have long walked alongside stroke survivors. A new system from Northwestern University and Chicago's Shirley Ryan AbilityLab lets them walk with them — through robotic legs. Published in Science Robotics, the therapist-exoskeleton-patient interaction (TEPI) framework virtually couples clinician and patient through paired lower-limb exoskeletons.
How TEPI Works
The therapist and stroke survivor each wear a lower-limb exoskeleton connected at hips and knees by a virtual spring-and-damper coupling. When the therapist moves, the patient feels calibrated assistance in real time — and vice versa. That closes a feedback loop conventional exoskeletons cannot: robotic devices normally impose fixed motion patterns, while human therapists cannot physically assist every joint at once.
Measurable Gait Gains
In evaluations with eight stroke survivors, TEPI outperformed conventional therapist-guided treadmill training. Participants achieved greater joint range of motion, took longer and higher steps and maintained matched muscle activation — while reporting high motivation and enjoyment. Nearly 800,000 Americans survive a stroke each year, according to the CDC, and gait recovery is one of the most demanding parts of rehabilitation.
Next Steps: Home and Overground
The team, led by Shirley Ryan AbilityLab scientific chair José L. Pons, plans to extend the framework to overground walking, stair climbing, and sit-to-stand transitions across multi-session studies. "Future work will also investigate more accessible and scalable systems that can extend therapist-guided rehabilitation into the home and support remote care," said co-first author Matthew R. Short.
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Reporting based on coverage from Northwestern Now and Science Robotics.