If the part of the brain that handles language becomes damaged, language processing may switch to regions in the non-dominant hemisphere, new research shows.

Language and speech are processed in the cerebral cortex, specifically, two regions called Wernicke's area and Broca's area. They're usually located in the dominant hemisphere of the brain, which, for 97% of people, is the left side. (If you're right-handed, you're almost certainly in that group.)

For the current study, researchers at the Technical University of Munich recruited 50 healthy volunteers with no history of brain ailments and 15 patients with brain tumors in the language-focused areas of the brain. All of the subjects were verified to have left-brain dominance. The researchers used repetitive navigated transcranial magnetic stimulation (rTMS)* to map the parts of each subject's brain associated with language processing and speech, looking to see if there were any differences between the healthy subjects and the brain cancer patients.

Indeed there were. Patients with the brain tumors (pictured right) showed higher recruitment of the right hemisphere -- their non-dominant side -- in language function compared to the healthy patients. If truly the case, this would be an astounding example of neuroplasticity, the brain's ability to adapt and effectively rewire itself.

"It is the first lesion-based study that actually proves language plasticity as a shift to the non-dominant hemisphere by an anatomically traceable method," the researchers say.

However, the study has some key limitations. One of the biggest problems is that the brain tumor group was much older compared to the healthy group, and age can affect brain laterality. Moreover, the researchers were unable to precisely pinpoint particular cortical regions with boosted language function in the right hemisphere of the tumor group. More precise experiments with larger patient groups are needed to substantiate the current result.

The study was published in the Sept. 17th release of PLoS ONE.

Source: Krieg SM, Sollmann N, Hauck T, Ille S, Foerschler A, et al. (2013) Functional Language Shift to the Right Hemisphere in Patients with Language-Eloquent Brain Tumors. PLoS ONE 8(9): e75403. doi:10.1371/journal.pone.0075403

*This piece was corrected 10/3 because it mistakenly said that the researchers used fMRI brain scanning. They actually used a different procedure called rTMS.