People
who speak at least two languages are twice as likely as those who speak one
language to have normal cognitive functions following a stroke, a new study
finds.
Previous
studies have shown that bilingualism may play a part in delaying the onset of
Alzheimer’s disease.
A
stroke occurs when blood flow to a part of the brain is cut off. Burst of a
blood vessel in the brain causes “hemorrhagic stroke,” and blocking of blood
supply to the brain due to blood clot causes “ischemic stroke.” The cells in
the brain are deprived of oxygen and glucose they need to survive, which causes
the death of brain cells. If not detected early, stroke can cause permanent
brain damage or even death. [Read more What Causes Aging? Can The Process Be Slowed?]
Stroke
is a leading cause of disability in the US. Around 795,000 people have stroke
each year, of them 185,000 are first time strokes. Stroke kills almost 130,000 Americans
each year. On average, 1 person dies from stroke every 4 minutes in the US.
In
the new study, the researchers reviewed data of 608 stroke patients from
Hyderabad, India, who were part of the NIMS stroke registry between 2006-2013.
More
than half the patients were bilingual – defined by the researchers as speaking
two or more languages. Other factors such smoking, high blood pressure,
diabetes and age were also taken into account. [Read more Learning foreign languages may sharpen our minds]
The
team found that 40% of bilingual patients had normal cognitive functions
following a stroke, compared to about 20% of patients who spoke only one
language.
Bilingual
patients also produced better scores on post-stroke tests that measured
attention and ability to retrieve and organize information.
The
team was surprised to discover that there were no differences between bilinguals
and single language patients in the likelihood of experiencing aphasia – a
combination of a speech and language disorder caused by damage to the brain.
Moreover, Thomas Bak, M.D., study co-author at the University of Edinburgh in United Kingdom said: "The combined vocabulary of bilinguals can make it more difficult for them to find specific words. This may explain what appears to be a surprising result."
The results of the study may not be applicable to bilingual people all over the globe. In a multicultural city like Hyderabad, people commonly speak many languages such as, Telegu, Hindi, Urdu and English. [
"Constantly switching languages is a daily reality for many residents of Hyderabad," explains Alladi.
"The cognitive benefit may not be seen in places where the need to function in two or more languages isn't as extensive."
According to Kaul, the
findings do not necessarily suggest people who
speak one language should begin learning another. He believes any mentally
challenging task could be helpful.
"Our study suggests that
intellectually stimulating activities pursued over time, from a young age or
even starting in mid-life, can protect you from the damage brought on by a
stroke," says Kaul.
The United
States is largely monolingual. In fact, only about 15-20 percent of Americans
consider themselves bilingual, compared to 56 percent of Europeans surveyed in
2006 by the European Commission.
The study
was reported in the American Heart Association journal Stroke.