Super Brains and Dementia

We have a lot of evidence showing that the older you get the more problems we start having with our brains. In healthy adults they tend to shrink, and then they become prone to diseases, not excluding our nemesis of Alzheimer’s disease. We always assumed that these changes are fixed.  But then how do we explain exceptional older adults.

Exceptional adults are examples of what is possible, and not what is statistically likely.

When Emily Rogalski from Northwestern University looked at two groups of Chicago-area older adults of 80 years and older with similar education--12 who had exceptional memory, and ten normal older adults--she was not ready for the findings.  Her study reported that the exceptional group not only had sharp memories--as sharp as people 20 to 30 years younger--but she also found that their brains appear younger.  When compared to 50 to 65 year olds, these exceptional older adults had a thicker outer layer of the brain important for memory, attention and other thinking abilities. While in another region deep in the brain, they had thicker anterior cingulate--which is responsible for attention. Not only was there no shrinkage, these exceptional older adults show youthful brains.

Henrikje van Andel-Schipper was the oldest woman in the world when she died at age 115 in 2005. After Gert Holstege, from Groningen University, undertook a post-mortem of her brain he found few signs of Alzheimer's or other diseases. It seems that these exceptional people have escaped the normal effects of aging.

Jessica Evert from Ohio State University and her colleagues support this view. When examining death from heart disease, nonskin cancer, and stroke, 87% of male and 83% of female centenarians that they studied delayed or escaped these diseases.

If we apply the concept of escapers to the brain, then we can say that exceptional older adults escape from damaging their brain.  As far-fetched as this might seem, researchers are now focusing on studying how we might be developing the brain in detrimental ways. Known as negative plasticity—by not exercising the brain, learning things the wrong way and responding to stress—could be  causing the brain to shrink and develop inefficiently. 

Although brain shrinkage is related to aging, we now know it is not fixed and invariable. If the brain shrinks because of trauma that we impose upon it, then we need to start taking better care of our brain. The brain likes to be challenged, to be happy, stress free, fed well and exercised--just like a precious teen.

Mario Garrett, Ph.D., is a professor of gerontology at San Diego State University and can be reached at mariusgarrett@yahoo.com

Highway Brain and the Earthquake Dementia

Our brain changes as we grow older. Changes dictated by the slow shrinking of the brain, creating a widening of the pockets inside the brain. And there are also changes in parts of the brain used for certain tasks.

We are learning more about these changes because of a new technique of seeing into the brain called functional Magnetic Resonance Imaging. The functional part is that we can have people perform an activity while we watch their brain’s activity.

On the whole we witness variable results when we compare older and younger adults. Sometimes there is less activation among older adults, sometimes more activation, and invariable older and younger adults differ in which parts of the brain they use while undergoing the same activity (eg reading.)

The brain is a wonderfully clever but lazy organ. It works as hard as it has to and nothing more. Which is why sometimes it is hard to learn, because we have to persuade it that it has to. Like any precocious teenager, they will do enough to get by. The brain is like that teen.

David Snowdon studies 678 nuns—Catholic members of the School Sisters of Notre Dame—who are 75 to 106 years of age. The nuns undergo extensive testing and when they die, his team examines their brain. It was Snowdon who first reported a very strange anomaly. He found that a third of the nuns who for all intents and purposes acted normally throughout their life, when they performed the autopsy, they found that their brain had the disease of Alzheimer’s. This finding has since been found in other populations, notably in Sweden where otherwise healthy and competent older adults were found to have diseased brains.

The quick answer to this finding is that some people have “cognitive reserve”. Basically they have more brains and so they can afford to loose some to the disease.  But this does not explain why certain occupations—academic, research, engineering and art, occupations that develop your brain—do not protect you from dementia. It seems that the reserve is not just in size but that the reserve need to be in quality—how you develop and grow your brain.

Like a precocious teen, the brain knows of ways of escaping from its many duties. Doing things that we take for granted—like reading for example—the brain develops an interstate of neural pathways that makes it easy for it to accomplish that repetitive task.  What seems to work is when we trick our brain in developing new pathways.

In a 21-year study of older adults, 75 years and older, Robert Katzman and Joe Verghese, found that mental activities like reading books, writing for pleasure, doing crossword puzzles, playing cards as well as playing golf, swimming, bicycling, dancing, walking for exercise and doing housework did not offer any protection against dementia with some important exceptions:  frequent dancing, playing an instrument and playing board games.

Creating new pathways is what works. When disease interferes with the flow of traffic, then having alternate pathways helps divert traffic. This is what seems to be happening and why it is not just the size of the brain but the networks that we develop that protect us from dementia.

Mario Garrett, Ph.D., is a professor of gerontology at San Diego State University and can be reached at mariusgarrett@yahoo.com