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York researchers demonstrate that lifelong use of two or more languages helps delay the onset of Alzheimer's and other forms of dementia

York researchers demonstrate that lifelong use of two or more languages helps delay the onset of Alzheimer's and other forms of dementia

An elderly woman in a wheel chair being helped up by a caregiver


York University Distinguished Research Professor Ellen Bialystok’s research uses both behavioral and neuroimaging methods to examine the effect of bilingualism on language and cognitive processes across the lifespan.

In 2007, Bialystok, a Professor in the Department of Psychology, Faculty of Health, led a research study helping to demonstrate the lifelong use of two languages can help delay the onset of dementia symptoms by four years, allowing these individuals to function independently even though the disease may be present.

The study, which was published in the February 2007 issue of Neuropsychologia (Vol.45, No.2), was conducted through the Rotman Research Institute, part of the Baycrest Research Centre for Aging and the Brain. Bialystok’s research team included psychologist Dr. Fergus Craik, and neurologist Dr. Morris Freedman, an authority on the mechanisms underlying cognitive impairment due to diseases such as Alzheimer's.

Researchers examined the diagnostic records of 184 patients with cognitive complaints. Of that group, 91 were monolingual and 93 were bilingual. The latter included speakers of 25 different languages. They found that 132 patients met criteria for probable Alzheimer's; the remaining 52 were diagnosed with other forms of dementia. Patient data included Mini-Mental State Examination (MMSE) scores (a measure of general cognitive functioning), and years of education and occupation. The MMSE scores were equivalent for the monolingual and bilingual groups at their initial visit to the clinic, indicating comparable levels of impairment.

The researchers determined that the mean age of onset of dementia symptoms in the monolingual group was 71.4 years, while the bilingual group was 75.5 years. This difference remained even after considering the possible effect of cultural differences, immigration, formal education, employment and even gender as influencers in the results. This finding has dramatic implications for public health.

In 2010, Bialystok was part of a team of Canadian researchers that uncovered further evidence that bilingualism can delay the onset of Alzheimer’s by up to five years.
The 2010 study, published in the journal Neurology, was led by the Rotman Research Institute, and examined the clinical records of more than 200 patients diagnosed with probable Alzheimer’s disease in the Sam and Ida Ross Memory Clinic at Toronto’s Baycrest Research Centre for Aging and the Brain.

Results of the 2010 study revealed that individuals who have been lifelong bilinguals have built up a cognitive reserve that allows them to cope with the disease for a longer period of time before showing symptoms. Bialystok’s research interests also include studies that examine the effect of bilingualism on a variety of aspects of cognitive development for children between the ages of approximately 4 and 8 years old. Bialystok and the team she leads at the Lifespan Cognition and Development lab, a cognitive neuroscience laboratory in the Department of Psychology at York, have also demonstrated that for young children, bilingual children have more advanced ability to solve problems in which there is misleading perceptual information than comparable monolingual children who are otherwise at about the same developmental stage. This processing advantage has been shown across a wide range of problem types, including both verbal and nonverbal domains.

A world-class researcher, Bialystok has published extensively in the form of books, scientific articles, and book chapters. She is a fellow of the Royal Society of Canada, Society for Experimental Psychology, American Psychological Society, and other professional organizations. Among her awards are the Canadian Society for Brain Behaviour and Cognitive Science Hebb Award (2011), Killam Prize for the Social Sciences (2010), York University President’s Research Award of Merit (2009), Donald T. Stuss Award for Research Excellence at the Baycrest Geriatric Centre (2005), Dean’s Award for Outstanding Research (2002), Killam Research Fellowship (2001), and the Walter Gordon Research Fellowship (1999).

To learn more about Professor Bialystok’s research, please visit her website.