The current economic doldrums have many Americans casting a worried eye on their retirement accounts. But in order to assure yourself of a comfortable old age, there’s another fund on which you should be keeping tabs — a mental one. Ask yourself: How big is my cognitive reserve?
Cognitive reserve is the term scientists use to describe the extent of the brain’s capacity to resist aging and degenerative conditions like Alzheimer’s disease. The notion that such a capacity could exist originated in a surprising discovery made almost 25 years ago, when the brains of 137 elderly residents of a nursing home were dissected after their deaths. Remarkably, researchers failed to find a direct relationship between the degree of Alzheimer’s disease detected in the residents’ brains (revealed by the presence of structures called plaques) and how impaired they had been while they were alive. In other words, some of these individuals were able to resist the ravages of the illness better than others — but how?
The neuroscientists from the University of California, San Diego, reported that the subjects whose abilities were less affected by Alzheimer’s were those with bigger brains and a greater number of neurons — suggestive evidence that keeping their brains active had built a bulwark against decline.
Since then, the idea that a deep cognitive reserve provides protection has received support from many different quarters. Research on bilingualism by Ellen Bialystok of York University in Toronto, for example, has demonstrated that speaking more than one language delayed the onset of Alzheimer’s symptoms by an average of five years. In a study published last year in the journal Cortex, Bialystok and her co-authors used brain scans to measure the extent of brain atrophy in monolingual and bilingual individuals who showed early signs of Alzheimer’s disease. The amount of atrophy in the bilinguals’ brains was much greater — indicating that even though their physical disease was more advanced than the monolinguals’, they’d been able to keep functioning at the same level. Bialystok theorizes that the lifelong mental exercise required to speak multiple tongues — remembering which word belongs to which language — helps bilinguals augment their cognitive reserves.
Now a new study suggests that mental activity can offset the effects not just of degenerative diseases, but of normal aging as well. In an article published this month in the journal Neurobiology of Aging, Nina Kraus and her colleagues at Northwestern University measured the ability of subjects to respond quickly and accurately to sounds that they heard. Some of the study’s participants were young adults aged 32 and under, while others were between 46 and 65 years of age; some were experienced musicians, and some were not. Kraus found that the middle-aged musicians, who’d spent decades honing their craft, outperformed not only their nonmusician peers but also the nonmusicians many years their junior. The mental rigor required by the practice of music effectively acted as an antidote to aging, keeping their nervous systems youthful.
We’ve all been taught the importance of beginning early in saving money for retirement. Accumulating mental capital — by learning to play an instrument, speak in a foreign language or master any complex skill — works the same way. If you want a generous cognitive reserve to see you through your golden years, you’d better start contributing now.