Speaking More Than One Language Can Delay Alzheimer's


For the first time, scientists have physical evidence that having the ability to speak more than one language can delay the onset of Alzheimer’s disease. One question that comes to mind—and which the study did not answer—is whether one has to learn a second language early in life to enjoy this benefit.

Bilingualism can delay, but not prevent, Alzheimer’s

Earlier studies have explored the impact of knowing more than one language on the onset of Alzheimer’s disease, but they did not uncover physical evidence. One such study was from Rotman Research Institute, which reported that patients who spoke two languages were diagnosed with Alzheimer’s disease 4.3 years later and had onset of symptoms five years later than patients who spoke only one language.

This new study, however, from researchers at St. Michael’s Hospital, found evidence on computed tomography (CT) scans that patients with probably Alzheimer’s who can speak more than one language have twice as much brain damage as people who speak only one language before they show symptoms of Alzheimer’s disease.

According to neuroscientist Tom Schweizer, who headed the study, “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.”


Although patients in both groups performed similarly on all measures of cognitive tasks, the CT scans of patients who spoke two languages revealed twice as much brain atrophy as those who spoke one language.

People who speak two language exemplify the “use it or lose it” adage, because their brains must constantly switch from one language to another. Schweizer noted that this increased activity may make their brains better able to compensate when Alzheimer’s begins to develop.

It’s important to note that this study and others on this topic do not suggest bilingualism prevents Alzheimer’s disease. Researchers also do not know whether once Alzheimer’s symptoms develop in bilingual individuals, the disease progresses at an accelerated rate, or if people must learn a second language early in life to benefit from this delay.

What the results of these studies do support, however, is the importance of keeping the brain active, whether the activity be learning a new language or a new hobby, reading, doing crossword puzzles, reading and playing music, and other activities that challenge the brain.

For now, the study’s authors noted that speaking more than one language “appears to contribute to increased CR [cognitive reserve], thereby delaying the onset of AD and requiring the presence of greater amounts of neuropathology before the disease is manifest.” Further research will be conducted using more patients and the use of magnetic resonance imaging (MRI) scans.

Craik FI et al. Neurology 2010 Nov 9; 75(19): 1726-29
Schweizer TA et al. Cortex 2011 Oct; doi: 10.1016/j.cortex.2011.04.009