For the first time, Toronto scientists have physical evidence that people who speak more than one language could delay the onset of Alzheimer’s disease than their monolingual counterparts.
The researchers at St. Michael’s Hospital found that bilingual people have twice as much brain damage as unilingual people before they exhibit symptoms of Alzheimer’s disease.
“This is unheard of – no medicine comes close to delaying the onset of symptoms and now we have the evidence to prove this at the neuroanatomical level,” said lead researcher Dr. Tom Schweizer, a neuroscientist at St. Michael’s Hospital.
To conduct the study, the researchers studied the CT scans of 40 patients whose cognitive skills — including attention, memory, planning and organizational abilities — were found on testing to be similar.
Dr. Schweizer and his colleagues studied the CT scans of 40 patients whose cognitive skills, including attention, memory, planning and organizational abilities, were found on testing to be similar.
Half the patients were fluently bilingual while the other half spoke only one language.
The scans of the bilingual patients showed twice as much atrophy in areas of the brain known to be affected by Alzheimer’s.
Schweizer said that bilingual people are constantly using their brain and keeping it active, which may contribute to overall brain health. That’s why many physicians encourage older people to do crossword puzzles or Sudoku.
Previous observational studies have found that bilingualism delays the onset of Alzheimer’s symptoms by up to five years, but this is the first to find physical proof through CT scans.
Although being bilingual appears to stave off onset of the symptoms, Schweizer stressed that bilingualism does not prevent someone from developing Alzheimer’s. Once symptoms start to appear in bilingual people, it is not clear whether the disease progresses at an accelerated rate.
The findings appear online in the journal Cortex.