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June 29, 2006 -- StrokeStroke experts have successfully tested a noninvasive approach to help the brain recover from stroke.
Felipe Fregni, MD, PhD, and colleagues describe their experiment in the journal Stroke's early online edition. Fregni works in Boston, at the Harvard Center for Noninvasive Brain Stimulation.
Fregni's study included 15 stroke patients. The 11 men and four women had had a stroke at least a year earlier and had mild to moderate movement problems due to stroke.
The patients were 38-75 years old (average age: 56). Most had suffered damage to their brain's left hemisphere.
First, the patients took a battery of mental tests that covered memory, attention, and other cognitive skills. They also tested their motor control of their hands. Each patient had one hand that had stroke-related movement problems.
Magnetic Stimulation
Fregni and colleagues split the patients into two groups.
One group received repetitive transcranial magnetic stimulation (rTMS), in which a coil is positioned on the outside of the head. The coil produces a magnetic field to alter electrical activity in the brain.
For comparison, the second group of patients got a sham treatment that didn't affect their brains at all.
The patients received one 20-minute daily session of rTMS or the sham treatment for five days. They repeated the mental tests and hand movement test during the treatment period and again two weeks later.
The rTMS group showed improvement in motor function performance for their stroke-damaged hand; those benefits lasted for two weeks. They showed no signs of treatment-related seizuresseizures or mental problems, and their healthy hand was unaffected.
No changes were seen in the sham treatment group.
Coaxing the Brain Back Into Action
The rTMS results were seen only when the researchers treated the side of the patients' brains that hadn't sustained stroke damage. The rTMS relaxed that part of the brain; as a result, the stroke-damaged brain areas stepped up their activity.
The principle is similar to wearing an eye patch over your dominant eye to force the weak eye to get stronger.
The study's few reported side effects were mild headache (one patient in each group), increased anxiety (one patient in the rTMS group) and increased tiredness (one patient in the comparison group).
Since their experiment was small, Fregni and colleagues call for more rTMS studies in other groups of stroke patients.
SOURCES: Fregni, F. Stroke, June 30, 2006; rapid access online edition. News release, American Stroke Association.