By Steve Connor, Science Editor
Stroke patients with brain damage can recover more quickly with the help of small electric currents applied to the head from electrodes on the skull, a study has found.
The tiny electric currents are believed to stimulate the re-growth of nerve connections in the brain that have been lost as a result of oxygen starvation caused by stroke, scientists said. Tests on a small group of healthy volunteers have shown significant improvements in the sort of brain activity that could also benefit stroke patients, the scientists said.
The research supports the idea that the brain can to some extent repair itself by rewiring and reconnecting itself to bypass damaged areas, according to Professor Heidi Johansen-Berg of Oxford University.
“The brain is far more dynamic than previously thought … The connecting fibres of the brain change their structure with training,” Professor Johansen-Berg said. “After stroke, there is widespread subtle damage to connecting fibres, far beyond the stroke itself. However, with repeated practice, patients can increase activity in brain areas that have been disconnected,” she told the British Science Festival at Bradford University.
Tests on stroke patients found that playing computer games every day could stimulate the brain to bypass the damaged areas by “recruiting” new connections between nerve cells in undamaged areas. The scientists extended the research by using small electrical currents that are believed to stimulate connections between and re-growth of nerve cells or blood vessels.
The technique involves placing rubber pads on each side of the skull. Electric currents of around 1 to 2 milliamps are passed from one electrode to the other. Stroke damage usually affects only part of the brain, which means that other areas attempt to compensate by a “rebalancing” process. “This change in the balance of activity is most common in poorly recovered patients. It is possible that rebalancing the brain might provide a route to better recovery,” Professor Johansen-Berg said.