Language Recovery Aided By Noninvasive Brain Stimulation; May Soon Be Used To Treat Stroke-Related Aphasia

Brain
Stroke survivors may find language recovery easier after noninvasive brain stimulation. Brain | alles-schlumpf/Flickr

Strokes affect 1.7 million Americans each year and are the third leading causing of death in the United States. Close to 30 percent of stroke survivors have long-lasting aphasia, a condition that keeps stroke survivors from understanding and using language, and thus prevents them from reading, writing, and speaking. It occurs when strokes happen in the regions of the brain responsible for language.

While speech therapy techniques have been used to reteach language to stroke patients, they are often ineffective, as they fail to stimulate the brain, and instead confront people who have no language function with materials and words they do not understand.

A new study has tested the efficacy of noninvasive brain stimulation (NBS) alongside speech therapy in the effort to teach stroke survivors language. In a small study of 24 stroke survivors with aphasia, 13 received repetitive transcranial magnetic stimulations (rTMS, a form of NBS, to the right side of their brain alongside 45 minutes of speech therapy), while a control group of 11 participants received placebo-like NBS that did not stimulate their brains, as well as 45 minutes of speech therapy.

The results of this experiment were astounding. The groups receiving rTMS improved their language use and comprehension three times more than the group receiving only speech therapy. Alexander Thiel, M.D., study lead author, explained, "TMS had the biggest impact on improvement in anomia, the inability to name objects, which is one of the most debilitating aphasia symptoms."

Similarly, when researchers looked at the activity in the language portions of the TMS-receiving patients, they found greater activation in language portions of the brain, and therefore far more improvements in these patients. As a result, the researchers noted a trend among these patients toward a higher change in comprehension, writing, and recognition of objects.

It is important to note where exactly the rTMS stimulation was applied. The rTMS was applied for 20 minutes to the right side of the brain. However, the language centers of the brain are on the left side of the brain. Researchers chose to stimulate the right side in the effort to stop its function. Of course, the functions of the right brain were inhibited within reason, and patients did not suffer any negative effects to the right brain. However, blocking the right side's function seemed to make the left hemisphere more susceptible to learning, which proved useful during speech therapy sessions, as the patients learned and improved more than those without brain stimulations.

The researchers assure that NBS may be a new and safe way to treat stroke-related aphasia. During the study, no serious negative effects occurred during or after brain stimulation therapy. Similarly, none of the patients receiving the stimulations to their brain suffered a decline in language acquisition — only improvements were seen.

"For decades, skilled speech and language therapy has been the only therapeutic option for stroke survivors with aphasia. We are entering exciting times where we might be able in the near future to combine speech and language therapy with non-invasive brain stimulation earlier in the recovery. This could result in earlier and more efficient aphasia recovery and also have an economic impact," Thiel added.

The researchers intend to perform larger trials of this new technique. They hope to test different modalities of noninvasive brain stimulation in order to identify ways to help everyone with aphasia, regardless of the time of their stroke as well as the seriousness of their language loss.

 

Source: Theil A, Hartmann A, Rubi-Fessen I, et al. Effects of Noninvasive Brain Stimulation on Language Networks and Recovery in Early Poststroke Aphasia. Stroke. 2013.

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