A robot nicknamed Howard may help people regain the use of a hand weakened by brain damage caused during a stroke.
While robotic therapy has been explored for leg and shoulder rehabilitation, the Hand-Wrist Assisting Robotic Device (HWARD) is one of the first to attempt robotic therapy for the hand, says Dr. Steven Cramer, associate professor of neurology, anatomy and neurobiology at the University of California at Irvine.
Cramer and his team tested the device in 13 patients with moderate weakness in the right hand and wrist stemming from a stroke. Each participant received 15 two-hour sessions over a period of three weeks. Sessions involved virtual reality activities and games, and focused on elements such as movement, speed, precision and force. Therapy began three months after stroke.
HWARD was designed to complete movements patients were able to start but not finish. During grasp and release exercises, HWARD would complete the grasping motion begun by a patient who was unable to form a grip.
“Whatever their hand couldn’t do, the robot would then complete for them. So it’s not just whipping the hand back and forth like a hockey puck, because the brain doesn’t do well with that. They had to make the effort,” Cramer says. The theory behind this is that the brain can learn from the hand.
“The brain’s central cortex is listening to all of this and feeds the information to the motor cortex (the parts of the brain involved in controlling movement). So in effect the completion by the robot after that attempt is educating the motor cortex.”
After three weeks of therapy, study participants showed significant improvement in tests of hand movement, and brain scans showed expansion in areas devoted to hand movement.