Medical resident Jarod Roland, MD, tries out a device that detects electrical activity in his brain and causes his hand to open and close in response to brain signals. A new study shows that this device can help chronic stroke patients recover some control over their paralyzed limbs. Credit: Leuthardt Lab

Stroke patients are now able to use brain power to open and close a device fitted over their paralyzed hands thanks to a new brain-computer interface.

Researchers from Washington University School of Medicine in St. Louis have developed the device that allow participants to train the uninjured parts of their brains to take over the functions previously performed by the injured areas.

“We have shown that a brain-computer interface using the uninjured hemisphere can achieve meaningful recovery in chronic stroke patients,” Dr. Eric Leuthardt, a professor of neurosurgery, neuroscience, biomedical engineering and mechanical engineering and applied science and the study’s co-author, said in a statement.

The device—called the Ipsihand—is comprised of 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 is able to detect 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.

Stroke is the leading cause of acquired disability among adults with about 700,000 people living in the U.S. experiencing a stroke annually.

Stroke victims typically regain some abilities in the first weeks following the episode but that progress generally plateaus after about three months.

“We chose to evaluate the device in patients who had their first stroke six months or more in the past because not a lot of gains are happening by that point,” co-senior author Dr. Thy Huskey, an associate professor of neurology at the School of Medicine and program director of the Stroke Rehabilitation Center of Excellence at The Rehabilitation Institute of St. Louis, said in a statement. “Some lose motivation.

“But we need to continue working on finding technology to help this neglected patient population.”

The areas of the brain that control movement are generally on the opposite side of the body as the limbs they control.

However, 10 years ago, the research team discovered a quirk where a small area of the brain that played a role in planning movement on the same side of the body.

The researchers found that specific electrical signals indicate movement planning of the left hand initially appear in a motor area on the left side of the brain and then within milliseconds the right sided motor areas become active and the movement intention is translated into actual contraction of muscles in the hand.

When a stroke victims left hand and arm are paralyzed it is proof of sustained damage to the motor areas on the right side of the brain. However, if the left side of the brain is frequently intact it is possible for many stroke patients to generate the electrical signal that indicates an intention to move, which doesn’t go anywhere to enact the actual movement because of the damage to the left side of the brain.

“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.

The researchers tested the device on 13 severely impaired stroke patients by training them to use the device at home where they were encouraged to use the device at least five days a week for 10 minutes to two hours a day.

Of the 13 participants, three dropped out and 10 completed the survey.

Each participant was given a standard motor skills evaluation that measured the patient’s ability to grasp, grip and pinch with their hands and make large motions with their arms every two weeks over the course of the study. The participants were also 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.

After three months the patients improved by an average of 6.2 points on a 57-point scale.

“An increase of six points represents a meaningful improvement in quality of life,” Leuthardt said. “For some people, this represents the difference between being unable to put on their pants by themselves and being able to do so.”

The study was published in Stroke.