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Using a pair of robotic exoskeletons, the system was developed at Northwestern University in Evanston, Illinois, and the Shirley Ryan AbilityLab hospital in nearby Chicago.
For many stroke survivors, the journey to recovery includes relearning to walk. Weakness, impaired coordination and reduced leg control can make even simple movements challenging. Recovery often requires months of intensive rehabilitation as patients work with physical therapists to regain mobility, independence and confidence.
In conventional physical therapy, therapists provide hands-on support and corrective guidance, often focusing on a single aspect of gait. Whole-body training can require multiple therapists.
Rehabilitation exoskeletons can increase training intensity and help patients practise walking for longer periods of time, but many rely on fixed movement patterns that do not fully adapt to a patient’s performance in real time, limiting therapists’ ability to deliver personalised care.
To address those gaps, the Northwestern and AbilityLab team developed a novel system called therapist-exoskeleton-patient interaction (Tepi). Using Tepi, a therapist and stroke survivor each wear a lower-limb exoskeleton virtually connected at the hips and knees. The virtual connection behaves like a combination of springs and shock absorbers, allowing therapists and patients to influence each other’s movements in real time.
The study demonstrated that therapists can effectively use Tepi to create more personalised rehabilitation experiences, supporting patients as they work toward recovery goals.
“By combining the hands-on adaptability of physical therapy with the scalability and precision of robotic systems, it can enable more comprehensive, whole-body gait training without requiring multiple therapists, while also introducing real-time responsiveness to patient performance – allowing support, resistance and feedback to be adjusted dynamically,” said Lorenzo Vianello, a researcher at AbilityLab and co-first author of a paper on the work.
In evaluations with eight stroke survivors, Tepi reportedly outperformed conventional therapist-guided treadmill training on several measures. Participants demonstrated greater joint range of motion and took longer, higher steps, while maintaining similar muscle activation. They also reported high levels of motivation and enjoyment.
“By allowing therapists to guide a patient’s movements through their own leg movements, Tepi could provide an impactful complement to conventional gait training for stroke rehabilitation, reducing physical effort that can contribute to fatigue and injury for therapists during hands-on therapy,” said the study’s co-first author Emek Barış Küçüktabak, who completed the research while a graduate research assistant.
Next, researchers plan to explore how the framework could be applied to other relevant activities, such as climbing stairs, standing up and sitting down.
“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, a postdoctoral researcher at the University of Delaware.
The work was published in Science Robotics.
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