Repetitive Transcranial Magnetic Stimulation May Aid Patients With Poststroke Aphasia

Barbara Boughton

September 22, 2010

September 22, 2010 (San Francisco, California) — A pilot study of a novel treatment for poststroke aphasia suggests repetitive transcranial magnetic stimulation (rTMS) may help prevent activation of areas in the brain that may hinder recovery in these patients.

In the small proof-of-concept study, aphasic stroke patients treated with rTMS also showed improved performance on language tests when compared with a control group, said presenting researcher Nora Weiduschat, MD, MPH, assistant professor of neuroscience in radiology at Weill Cornell Medical College in New York City.

Their results were presented at the American Neurological Association 135th Annual Meeting.

The study was initiated with the goal of attempting to suppress activation in the brain's right hemispheric structures, a phenomenon that hinders optimal functional reorganization in aphasic stroke patients, said Dr. Weiduschat, formerly of the University of Cologne in Germany, where the study was conducted.

"The idea was to suppress this right hemispheric activation in order to optimize outcomes," she said. Although there have been case studies of rTMS in aphasia in stroke patients, this was one of the first double-blind randomized controlled trials to test the intervention, Dr. Weiduschat said.

Suppressing Activation

During the study, 6 patients received 10 sessions of rTMS of 1 Hz for 20 minutes over the right Brodmann area (BA) 45 of the brain, whereas control patients had a sham treatment applied over the vertex, an area of the brain thought to have little effect on language, during 2 weeks.

Each rTMS session or sham treatment was delivered shortly before all patients (both in the intervention and sham groups) received conventional speech therapy. At baseline and after the treatment period, regional cerebral blood flow at rest and during an acoustic verb generation task was imaged with HSO positron emission tomographic scans in all patients.

Results indicated that at baseline, activation in the left and right BA 45 was comparable in both groups. But after the treatments ended, functional activity increased in the right BA 45 in the sham group, signaling that activation had shifted farther to the right in the brain.

In the rTMS intervention group, however, the researchers saw no further shift toward the right hemisphere, and patients who received rTMS also showed a trend toward a shift to the left BA 45, although this trend was not statistically significant, Dr. Weiduschat said.

The researchers were expecting to be able to document through imaging whether or not rTMS might hinder activation of brain regions associated with language problems in stroke patients, but they were surprised to find that those treated with rTMS also showed improved clinical outcomes.

When tested with the Aachen Aphasia Test, which measures verbal comprehension and speech generation, the control group improved by 8 points, whereas the rTMS group's scores improved by 20 of a possible 100 points. "It is a small study, so we were surprised to see clinically significant effects, or a 20% improvement in outcomes," Dr. Weiduschat said.

The researchers hypothesize that although rTMS may influence cortical activation in aphasic stroke patients in a positive way, speech therapy may help make these changes long-lasting. "We don't think that rTMS will replace speech therapy, but it might be a useful addition," Dr. Weiduschat said.

She noted that the researchers plan to perform a larger study to identify those patients who might benefit most from rTMS — for instance, patients with different types of aphasia or those with lesions in certain locations in the brain. "With a larger sample size, you could find indications and contraindications for rTMS," she said.

Novel Approach

"This study provides a fascinating preliminary result that should be further explored in a larger study," commented Steven R. Levine, MD, professor and vice chair of neurology at the State University of New York Downstate College of Medicine in New York City. "It's a small trial, so it's hard to say anything definitive from it, but it's a novel and significant approach," he said.

However, Dr. Levine noted that using rTMS for stroke patients would demand special expertise in this technology that not every hospital neurology department would have at its disposal.

"With such a small group as in this study, it's hard to know how carefully selected these patients were," he added. "But there seems to be a significant biological effect as well as a significant improvement in clinical outcomes. It seems believable, but I'd like to see it substantiated with larger numbers."

The study was supported by the Wolf-Dieter Heiss Foundation and the Marga and Walter Boll Foundation. Dr. Weiduschat and Dr. Levine have disclosed no relevant financial relationships.

American Neurological Association (ANA) 135th Annual Meeting: Abstract T-99. Presented September 14, 2010.


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