For stroke therapy, a device that walks the walk
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Close-up of the device
that may help correct a motor-control deficit in stroke patients,
and enable them to relearn to walk properly.
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larger image)
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atch someone who has had a stroke walk and you
likely will see a teetering, assymetric gait that includes a sideways
leg swing, a locked knee and uneven steps. Those characteristics, which
often develop after the stroke, appear to cause patients’ walking
difficulties.
Current physical therapy techniques attempt to eliminate
those characteristics; however, the characteristics may be compensations
for an underlying motor-control deficit, says Kreg Gruben, an associate
professor of biomedical engineering and kinesiology.
A more effective therapeutic approach is to correct
the motor-control deficit that’s causing the characteristics,
he says. To do that, he and graduate student Matthew Schmidt developed
a system (pictured) that looks somewhat like an exercise bike, but uses
feedback to guide users to push a pedal in ways that retrain their natural
muscle coordination patterns.
The invention is based on Gruben’s research,
which suggests that the underlying cause of stroke patients’ walking
difficulties is not just muscle weakness, but rather a control mix-up
in the ratio of torque at the hip to torque at the knee as the patient
attempts to walk. “After stroke, the hip provides more of the
effort than the knee,” says Gruben. “The net effect is it
tips you over backwards, and the unusual walking behaviors are likely
to be compensations that enable patients to ‘walk,’ in spite
of the control abnormality.”
The device could help patients regain a “normal”
distribution of effort between the hip and knee. While the system may
provide therapy to people who’ve lost muscle coordination due
to stroke, traumatic brain injury, cerebral palsy or Parkinson’s
disease, it also could provide training or rehabilitation to athletes
who want to strengthen—or avoid re-injuring—specific muscle
groups.
