A person whose left hand and arm are paralyzed has sustained damage to the motor areas on the right side of the brain. But the left side of the person's brain is frequently intact, meaning many stroke patients can still generate the electrical signal that indicates an intention to move. The signal, however, goes nowhere since the area that executes the movement plan is out of commission.

"The idea is that if you can couple those motor signals that are associated with moving the same-sided limb with the actual movements of the hand, new connections will be made in your brain that allow the uninjured areas of your brain to take over control of the paralyzed hand," Leuthardt said.


That's where the Ipsihand, a device developed by Washington University scientists, comes in. The Ipsihand comprises a cap that contains electrodes to detect electrical signals in the brain, a computer that amplifies the signals, and a movable brace that fits over the paralyzed hand. The device detects the wearer's intention to open or close the paralyzed hand, and moves the hand in a pincer-like grip, with the second and third fingers bending to meet the thumb.

"Of course, there's a lot more to using your arms and hands than this, but being able to grasp and use your opposable thumb is very valuable," Huskey said. "Just because your arm isn't moving exactly as it was before, it's not worthless. We can still interact with the world with the weakened arm."

Leuthardt played a key role in elucidating the basic science, and he worked with Daniel Moran, PhD, a professor of biomedical engineering at Washington University School of Engineering & Applied Science, to develop the technology behind the Ipsihand. He and Moran co-founded the company Neurolutions Inc. to continue developing the Ipsihand, and Leuthardt serves on the company's board of directors. Neurolutions funded this study.

To test the Ipsihand, Huskey recruited moderately to severely impaired stroke patients and trained them to use the device at home. The participants were encouraged to use the device at least five days a week, for 10 minutes to two hours a day. Thirteen patients began therapy, but three dropped out due to unrelated health issues, poor fit of the device or inability to comply with the time commitment. Ten patients completed the study.

Participants underwent a standard motor skills evaluation at the start of the study and every two weeks throughout. The test measured their ability to grasp, grip and pinch with their hands, and to make large motions with their arms. Among other things, participants were asked to pick up a block and place it atop a tower, fit a tube around a smaller tube, and move their hands to their mouths. Higher scores indicated better function.

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