Bilingualism Benefit in Delaying Alzheimer’s Gets Physical Support

Earlier this year I summarized a study reporting that bilingual seniors had a delayed onset of the cognitive symptoms of Alzheimer's, compared with monolingual people.  Shortly afterwards another report described results from the Nun Study that indicate no protective effect of multilingualism against Alzheimer's disease.  Now the original researchers, who are from Toronto, report brain imaging results that support their contention, namely that bilingualism contributes to cognitive reserve, and does, indeed, help postpone the cognitive signs of Alzheimer’s. Their findings are reported in the journal Cortex.    

The researchers argue that, if bilingualism is protective, the brains of bilinguals should show greater degeneration in the relevant Alzheimer areas, since their increased cognitive reserve (generated by mastering a second language) enables them to function at a higher level than would be expected from their actual level of disease. The team studied computed tomography (CT) scans from Alzheimer’s patients who had similar levels of education and cognitive skills (e.g. attention, memory, planning and organization skills); half of them were fluently bilingual, the rest were monolingual.

The bilingual patients had substantially greater brain atrophy than monolinguals in the brain areas traditionally used to diagnose Alzheimer’s disease, particularly in the temporal horn radius. 

These findings suggest that bilingualism – provided the patient uses both languages from time to time – may delay Alzheimer’s pathology from producing obvious cognitive defects. It seems that constant brain activity can indeed postpone the inevitable in people destined to develop the disease. The results will also add fire to the controversy about the value of widely-advertised brain training programs for the aging boomer.