Scientists at Federal Institute of Technology in Lausanne, Switzerland, studied the effects of utilizing a brain-computer interface and functional electrical stimulation on people who had strokes. Their findings were published Wednesday in the journal Nature Communications.
After a stroke, patients are often partially or totally unable to move the whole side of the body or just one arm or leg. A variety of therapies are used to bring this movement back, nerve stimulation being among them.
“The key is to stimulate the nerves of the paralyzed arm precisely when the stroke-affected part of the brain activates to move the limb, even if the patient can’t actually carry out the movement,” Dr. Jose del R. Millan, who holds the Defitech Chair at the institute, said in a press release. “That helps reestablish the link between the two nerve pathways where the signal comes in and goes out.”
In the clinical trial, 27 patients aged 36 to 76 were recruited between September 2012 and August 2015. They all had a similar lesion that resulted in moderate to severe arm paralysis after a stroke at least 10 months earlier.
Half the patients, who were treated with the dual-therapy approach, reported significant improvements. The other half were only treated functional electrical stimulation as a control group and the results were not as noticeable.
“Patients who received the BCI treatment showed more activity in the neural tissue surrounding the affected area,” Mill said. “Due to their plasticity, they could help make up for the functioning of the damaged tissue.”
The BCI system was linked the patients’ brains to computers using electrodes. Each time the electrical activity was identified, the system stimulated the arm muscle that controls wrist and finger movements.
After 10 one-hour sessions, scientists noted a significant improvement in arm mobility. After the full round of treatment, test scores were more than twice as high as those of the second group.
In the second group, patients also had their arm muscles stimulated, but randomly. As with the control group, the researchers found how much additional motor-function improvement could be attributed to the BCI system.
EEGs indicated an increase in connections among the motor cortex regions of their damaged brain hemisphere, the researchers said, which was linked to increased ease in movements.
Most importantly, the patients didn’t lose any of their recovered mobility in follow-ups six to 12 months later, the researchers report.
“BCI-FES therapy resulted in a statistically significant, clinically important, and lasting reduction of impairment in chronic moderate-to-severe stroke patients,” researchers wrote in the study. “In particular, the preservation of clinically relevant improvements at least six months after end of therapy is remarkable.”