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Prototype of exoskeleton arms may help stroke patients


Narrator:        Engineers at the University of California, Santa Cruz have developed a prototype of wearable exoskeleton arms that can be used for rehabilitation and physical therapy for people disabled by stroke or degenerative diseases. Jacob Rosen, an associate professor of computer engineering is an expert in medical robotics.

Rosen O/C:    Medical robotics is a subfield of robotics in which the robot has some effect on your health, whether improving it or facilitating a treatment like a surgical robot for surgery or exoskeleton for rehabilitation.

Rosen V/O:    In general, exoskeleton can be applied in three, potential subfields. It's applicable to healthy people in a military set up where they can carry heavy loads and also applicable to disabled people where muscles are not strong enough to even perform daily activities. The other type of application is physiotherapy. Nowadays, the amount of physiotherapy that a stroke patient, for example, can get is limited by how the therapist, if the therapist is tired or not.

Rosen O/C:    The more you move, the better you can recover from stroke. In a sense, you retrain the brain as part of the therapy. 

Rosen Demo O/C: So the robot would keep doing the same movement over and over again for as many times as the therapist would want.

Narrator:        Unlike other exoskeletons, Rosen's prototype include seven  degrees of freedom similar to the joints of the human arm, allowing the user wearing the system to reach 95 percent of the human arm's natural range of motion.

Rosen O/C demo:      In order to position and orient an object in space, you need six degrees of freedom. You need up and down, left and right, back and forth and three angles. The arm has seven degrees of freedom. Meaning, that if I'm holding this object, I have an extra degree of freedom. I can keep it in space and still do this movement. This movement is called a redundancy, meaning that my arm has more degrees of freedom that I need to manipulate object in space. This redundancy is a principal in physiological systems and the idea is if one of my joints is damaged, I can have still an extra joint to complete the task. You would see this concept in people that are disabled. Sometimes their wrist is fully-flexed and they don't have this movement, so they would hold a spoon and they would still be able to feed themselves because they have this extra degree of freedom to operate.

Narrator:        Rosen and his colleagues are working with the exoskeleton to come up with an effective human-machine interface that allows the brain's neural signals to control this seventh degree of freedom. The group is also working with Haptic technology, or sense of touch, to provide force feedback in a virtual reality system that can improve muscle strength. So, when will a device like this be available?

Rosen O/C:    The availability is related to the process of commercialization. There is not technological barrier in commercializing it. The issue is whether the market will be ready for a device like that....

Narrator:        For Science Today, I'm Larissa Branin.


For more information: UCSC Bionics Lab