Zero Order

The robotic exoskeleton revolution has been delayed

Posted in Uncategorized by Amy Ross on September 11, 2010

As a bioengineer, I look forward to the day when we can fashion new body parts, whether we build them or grow them out of tissue.  Until we get to that point, we’ll have to rely on assistive devices to help people with injuries or illness function better. Yesterday I attended a talk on the use of robotic devices for use in rehabilitation following neurological injuries.

The talk was given by George Hornby, a research scientist at  the Rehabilitation Institute of Chicago.  He looked at improving the ability to walk in patients who have experienced stroke or spinal cord injury (SCI).  In conventional therapy, patients are assisted by one or more physical therapists while they practice walking.  It’s very labor intensive for the PT, thus limiting the length of a therapy session.  Because the PT’s role is mechanical in nature and repetitive, it was thought that assistance could be automated.

Enter the robotic assistive devices. They attach to the patient’s lower body, and provide the support and assistance during walking.  RIC compared these devices to conventional therapy. Studies were done for patients with incomplete SCI and stroke.

Unfortunately, when compared to conventional therapy, the robots did not do well. Patients didn’t work as hard, their walking speed didn’t increase as much. Their gait and balance did not improve as much.   In the stroke patients, gait symmetry actually got worse!  Stroke patients with hemiparesis (weakness on one side of the body) have asymmetrical gaits because they take a shorter stride on their “bad” side.  The patient feels unsteady on that side and minimizes the time on that foot. When a patient works with a therapist, they receive correction in that respect, making the strides closer in length-something the robot doesn’t do.

Hornby concluded the talk by introducing a new apparatus involving a treadmill and large rubber bands .  The research team is looking at optimal size and stiffness of the rubber bands. No data on this yet as they’re still working on it. As a bonus, this setup costs <1% of the robotic device.

The best features of this talk were the videos Hornby played. To demonstrate that walking is patterned within the spinal nerves, he showed a video of half rat that had been injected with a certain drug. When placed on a treadmill, the rat began walking…even without input from a brain!   Freaky but cool.


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