Bilingual brains beat dementia                                            

                Among the several advantages of being fluent in more than one language a new one is emerging. Studies from medical centers in several countries reveal that persons who can speak two or more languages develop Alzheimer’s disease later than those who are monolingual.

Alzheimer’s disease and other forms of dementia are increasing, only partly because we are living longer. Lifestyle is an important factor. The same harmful habits that lead to obesity and type 2 diabetes generate inflammation and damage blood vessels in the brain. People who maintain normal weight and avoid daily spikes in blood sugar arrive in the eighth and ninth decade of life alert and with memories intact. Okinawan centenarians, of which there are many relative to their population, are the best examples. At the age of 100 many of them live independently and they are able to name all their great-grandchildren.

Contrary to medical thinking a half-century ago, we now know that regular physical exercise actually causes new brain cells to grow and it multiplies the connections between existing brain cells. Being bilingual also increases the connections between cells and so does learning how to play a new musical instrument or doing crossword or other puzzles. Being fluent in a second or third language adds two other dimensions known as cognitive reserve and the executive control system.

Think of cognitive reserve as an extra supply of brainpower. Imaging studies show that compared to monolingual persons, bilinguals have more grey matter volume than monolinguals in that part of the brain that deals with memory and language.

The executive control system acts as the brain’s manager. It helps us to avoid distractions and to focus on what is relevant. It makes it possible for us to switch back and forth between two different things going on in the mind, so that a person who can think in two languages is able to use one while ignoring the other. It develops early. I recall a three-year-old patient who spoke English, French and Vietnamese and never intermingled them.

Studies in various countries show that the age of onset of symptoms of Alzheimer’s disease is about 4 years later in bilingual persons than in monolinguals. It may even increase further in trilingual or quadrilingual persons although not all studies agree. It helps to be bilingual from infancy but these advantages occur in later language acquisition as well.