EMBARGOED FOR RELEASE UNTIL 4 PM ET, May 23, 2005
Magnetic Stimulation May Improve Stroke Recovery
St. Paul, Minn. -
A new therapy that uses magnetic pulses to stimulate the brain may improve recovery after a stroke, according to a study published in the May 24 issue of Neurology, the scientific journal of the American Academy of Neurology. The treatment, called repetitive transcranial magnetic stimulation, improved motor function in a small group of people. For the stimulation, an insulated wire coil is placed on the scalp, and a brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the outer part of the brain, called the cortex. The study involved eight people, ages 35 to 63, who had a stroke within the last year and were relearning to use their affected hands. They were compared to six people who had never had a stroke. The stroke patients received three sessions of magnetic stimulation to the side of the brain that had not been affected by the stroke using different parameters, including sham (mock) stimulation. A sham is the application of the procedure excluding the actual treatment being studied and is intended to address the question of a placebo effect. The six healthy participants were tested with the same battery of tests to evaluate the learning effect associated with repeated testing. All of the participants performed tests before and after the stimulations. The tests evaluated the motor function of the hand that was affected by the stroke. For example, reaction time was tested, along with how many finger taps could be performed over a period of time. The stroke patients improved by as much as 50 percent on some of the tests, such as reaction time when stimulation was applied to the side of the brain not affected by the stroke so as to reduce the motor activity of the unaffected hemisphere and promote an increase in the activity in the damaged hemisphere. Also, there was no improvement in the motor function following sham stimulation in the stroke patients. There was also no motor improvement in the healthy volunteers following repeated testing. “These results are exciting because magnetic stimulation is a non-invasive, painless therapy that can be done while patients are awake,” said study author Felipe Fregni, MD, PhD, of Harvard Medical School and Beth Israel Deaconess Medical Center in Boston. “These results need to be confirmed by larger studies with more patients, but the results are encouraging.” The study was supported by the Harvard Thorndike General Clinical Research Center at Beth Israel Deaconess Medical Center, a grant within the Harvard Medical School Scholars in Clinical Science Program, and by grants from the National Institutes of Health.