The brain has been studied for decades and still, some of its functions are not fully understood. A team of researchers from Johns Hopkins University made headway in brain function research by identifying the parts of the brain that control how people write words.
By studying patients who suffered from stroke, the researchers were able to identify the specific parts of the brain responsible in giving humans the capability to write. Stroke mainly affects the brain, and once it happens, it causes a wide array of complications on the parts of the brain affected.
In some cases, patients who recover lose some abilities that they can do easily in the past. For instance, stroke patients may lose the ability to spell or write words. In a new study published in the journal Brain, neuroscientists linked basic spelling problems with damage to different parts of the brain.
"When something goes wrong with spelling, it's not one thing that always happens - different things can happen and they come from different breakdowns in the brain's machinery," says Brenda Rapp, a professor in the Department of Cognitive Sciences and lead author of the study.
"Depending on what part breaks, you'll have different symptoms," she adds.
The researchers collected and analyzed 15 years' worth of cases, in which 33 patients showed signs of spelling problems after suffering from stroke. The patients suffered from two types of brain impairments: working-memory problems and long-term memory difficulties.
The researchers explained that forgetting how to spell previously-known words correctly falls under long-term memory difficulties. Patients with this impairment may write a predictably spelled word like "bark" correctly but they tend to make educated guesses with other words with a more unpredictable spelling. They may spell "laugh" as "laff."
On the other hand, while those with working-memory issues know how to spell words, they have difficulty picking out which letters to use or putting them in the proper order. "Mouse" may be spelled "muos" or "nouse."
Using computer mapping, the scientists studied the brain lesions of each patient and discovered that among those with long-term memory loss, the damage was seen in two areas of the left hemisphere, one at the lower part toward the back and the other toward the front.
For patients who suffered working-memory impairment, the damage was also in the left hemisphere but in the upper part of the brain toward the back.
"The results constitute substantial progress in our understanding of the neural bases of the core processes of spelling and how these may be affected in acquired dysgraphia," the researchers conclude in the study.
"The findings also have broader implications for our understanding of the relationship between written language processes on the one hand and spoken language, visual and spatial processes on the other," they add.
The findings offer a clear evidence of how the brain works in spelling words. This is the first time a study pinpointed the exact mechanism of spelling and writing words.
Photo: Allan Ajifo | Flickr
