By mentally controlling the device with the help of a brain-computer interface, participants trained the uninjured parts of their brains to take over functions previously performed by injured areas of the brain, the researchers said.
"We have shown that a brain-computer interface using the uninjured hemisphere can achieve meaningful recovery in chronic stroke patients," said Eric Leuthardt, the study's co-senior author.
In the first weeks after a stroke, people rapidly recover some abilities, but their progress typically 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," said co-senior author Thy Huskey. "Some lose motivation. But we need to continue working on finding technology to help this neglected patient population."
"As the technology to pick up brain signals gets better, I'm sure the device will be even more effective at helping stroke patients recover some function," Huskey added.
The study was published in the journal Stroke on May 26.
Stroke is the leading cause of acquired disability among adults. About 700,000 people in the US experience a stroke every year, and 7 million are living with the aftermath.