Of the various effects that a stroke can have on a person, one of the most common is paralysis of one side of the body – needless to say, this has a severe impact on the victim’s ability to walk. Treatment often consists of therapists retraining the person’s body by repeatedly lifting their legs, guiding them through a proper walking pattern. The EU-funded CORBYS project aims to make such therapy easier for everyone involved by using a powered orthosis to move the patient’s legs in response to feedback from their brain.
Currently still in development, the robotic CORBYS device consists of a wheeled platform, at the front of which is a sort of exoskeleton that attaches to the patient’s legs. A pivoting attachment at the waist of that orthosis links it with the rest of the platform, but allows the patient to turn easily.
In the first phase of treatment, however, patients wouldn’t use the platform. Instead, they would have sensors placed on key points of their body, then walk on a treadmill. After observing their stroke-altered gait, a therapist would step in and manually guide their legs through a corrected walking pattern. Feedback from the sensors would be used to create a computer model of that target gait.
That model would be uploaded into the CORBYS platform, which would then use its powered orthosis to guide the patient through the proper movements, once they were “strapped in.” The patient would be free to walk around as they wished, the platform moving, turning, starting and stopping along with them, correcting their gait at the same time. As with other therapeutic exoskeletons, it wouldn’t force the patient to walk even if they didn’t want to, but would instead respond to their self-initiated movements.
The platform would incorporate several physiological sensors, including an EEG (electroencephalography) cap. Using these, the system software would be able to keep track of parameters such as heart rate, body temperature, muscle activity, and stress levels. That data would let the system know how the patient was responding to the treatment, and fine-tune it if needed – if the patient were getting particularly stressed at having to move one leg in a certain direction, for instance, the platform would temporarily ease up on that aspect of the training.
As the treatment progressed and the patient’s gait improved, the therapist could set the platform to more advanced modes, which would take the patient closer to ultimately being able to walk normally again.
Eleven research institutes in six countries are involved in the project, which is headed by Germany’s University of Bremen. The platform is expected to completed in a year, at which point human trials in Germany and Slovenia will begin. Similar systems already in use include the Lokomat and the Walkbot.