Shedding new light on the mechanics of language and memory, the researchers found that basic spelling difficulties may be linked to seemingly unrelated regions of the brain.
“When something goes wrong with spelling, it is not one thing that always happens — different things can happen and they come from different breakdowns in the brain’s machinery,” said lead author Brenda Rapp, professor at Johns Hopkins University in the US.
“Depending on what part breaks, you’ll have different symptoms,” Rapp noted.
The findings appeared in the journal Brain.
The researchers studied 15 years’ worth of cases in which 33 people were left with spelling impairments after suffering strokes.
Some of the people had long-term memory difficulties, others working-memory issues.
With long-term memory difficulties, people ca not remember how to spell words they once knew and tend to make educated guesses.
They could probably correctly guess a predictably spelled word like “camp,” but with a more unpredictable spelling like “sauce,” they might try “soss.”
With working memory issues, people know how to spell words but they have trouble choosing the correct letters or assembling the letters in the correct order — “lion” might be “liot,” “lin,” “lino,” or “liont.”
The team used computer mapping to chart the brain lesions of each individual and found that in the long-term memory cases, damage appeared on two areas of the left hemisphere, one towards the front of the brain and the other at the lower part of the brain towards the back.
In working memory cases, the lesions were primarily also in the left hemisphere but in a very different area in the upper part of the brain towards the back.
The researchers believe that the findings could lead to improved behaviuoral treatments after brain damage and more effective ways to teach spelling.