A small but promising study suggests that magnetic stimulation of the brain could aid the recovery of some stroke patients.
When a stroke occurs on one side of the brain, some patients behave as though the opposite side of their body no longer exists. (The right side of the brain controls the left side of the body and vice versa.) The condition is known as hemispatial neglect and it’s most common with an injury to the right hemisphere. These patients are unable to focus on the left side of their body or the left part of the world, even though their ability to see is completely normal. They frequently bump into objects and may develop rather unusual habits. A male patient, for instance, may shave only one side of his face.
Rehabilitation usually involves various drills designed to draw attention to the neglected side of the body, but the therapy is challenging and not always successful.
Neurologists have long known that in a healthy brain both hemispheres tend to counterbalance each other. After a stroke, the unaffected hemisphere may become overactive because it is no longer held in check by the damaged side. This one-sided over-activity could contribute to hemispatial neglect.
But Italian researchers now believe it’s possible to restore balance by applying magnetic stimulation to the overactive part of the brain. “We use magnetic fields to induce currents which interact with brain circuits ... and this reduces the excitability of neurons,” explained Marco Bozzali, a neurologist at the Santa Lucia Foundation in Rome. The stimulation is painless. It feels like a tapping sensation on the top of the scalp.
For a pilot study, Dr. Bozzali and his colleagues recruited 20 stroke patients suffering from hemispatial neglect. Half the patients underwent 10 magnetic stimulation sessions over two weeks. The other half received “sham” therapy that didn’t stimulate the neurons. Both groups also received conventional rehab therapy.
The volunteers were given tests to measure their progress. Those who received magnetic stimulation performed 16 per cent better on these tests at the end of the two-week treatment period. After another two weeks with rehab alone, they showed a 22-per-cent improvement from their original condition. Patients who got the sham treatment showed no improvement, according to the findings published in the journal Neurology.
“I think this study represents an exciting first step in the rehabilitation of neglect,” said Heidi Schambra, a neurologist at Columbia University Medical Center in New York. “But the big question is, will this help long term,” added Dr. Schambra, who co-authored a journal editorial on the innovative treatment.
Dr. Bozzali agrees a lot more research must be done before magnetic stimulation is integrated into patient rehab.