Brain stimulation could speed stroke recovery

For people who've had a stroke, a treatment that involves applying an electric current to the brain may help boost recovery of their mobility, a small clinical trial found.

Stroke is the most common cause of severe, long-term disability. Rehabilitation training, which helps patients re-learn how to use their bodies, can help some patients recover their ability to move. But it is often costly and time-consuming.

The new study looked at 24 patients; each had experienced a stroke that affected his or her ability move a hand and arm. Half of the participants were picked, at random, to receive nine days of rehab paired with a brain-stimulation technique known as transcranial direct current stimulation (tDCS). This method uses electrodes placed on the scalp to deliver constant, low electrical currents to specific areas of the brain. The other patients received a sham control treatment; they were fitted with electrodes but did not receive tDCS.

Compared to the control group, patients who received brain stimulation and rehab were better able to use their hands and arms for movements such as lifting, reaching and grasping objects, the researchers found. [10 Technologies That Will Transform Your Life]

"It was hard work for the patients. They had to come into the lab every day for two weeks," study co-lead researcher Heidi Johansen-Berg, a neuroscientist at the University of Oxford in England, told Live Science.

But the findings showed that "we can speed up stroke rehab with brain stimulation," Johansen-Berg said. "If we could routinely add brain stimulation to rehabilitation, this could help ensure that each patient reaches their true potential for recovery."

Magnetic resonance imaging (MRI) scans of the patients' brains revealed that these benefits, which lasted for at least three months, were associated with higher levels of activity in the brain's motor cortex (which controls voluntary movements) during movement, as well as an increased amount of brain matter in the motor cortex.

Previous research showed that tDCS could boost motor learning in healthy individuals. This led scientists to explore whether tDCS might also help reinforce patients' rehab training, the researchers said.

"The training was exhausting,like being in the gym every day, but it was huge fun," a study participant named Jan said in a statement. "Even after the first session, I felt as if I could do more, even though I was knackered. That made me go back every day, and I found it easier and easier."

The stimulation felt like amild tingle or a static electric shock, Jan said. "The worst part was that my head itched afterwards.

"I have definitely improved and benefited," Jan added. "People who haven't seen me say, 'Wow — you can move better now.'"

"For many patients after stroke, there is minimal opportunity to regain lost functions; tDCS has the potential to make the brain more plastic and so more responsive to treatment," said Marom Bikson, a biomedical engineer at City College of New York who was not involved in the study. "This is a well-controlled clinical trial toward that goal."

In the future, the researchers would like to conduct a larger clinical trial "to understand who benefits most or least from this approach," Johansen-Berg said. [5 Amazing Technologies That Are Revolutionizing Biotech]

How safe is this kind of brain stimulation? "This is an important question, as although this method is noninvasive — that is, we don't have to open up the skull — we are putting electrical current into people's brains, and this is not something that should be done lightly," Johansen-Berg said. "We need to be careful about how much current is being applied, and for how long.

"As this type of stimulation can boost learning, it could potentially be used as a cognitive enhancer in healthy people," Johansen-Berg said. "However, there is much still to be understood about how it works and what its long-term effects are, so we should be cautious before progressing to widespread use of the approach."

The new findings are published online today (March 16) in the journal Science Translational Medicine.