ot: Mental Reserves Keep Brains Agile - when Alzheimer pathology isn't Alzheimer traits

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December 11, 2007

Mental Reserves Keep Brains Agile

By JANE E. BRODY

http://www.nytimes.com/2007/12/11/health/11brod.html

My husband, at 74, is the baby of his bridge group, which includes a

woman of 85 and a man of 89. This challenging game demands an excellent

memory (for bids, cards played, rules and so on) and an ability to think

strategically and read subtle psychological cues. Never having had a

head for cards, I continue to be amazed by the mental agility of these

septua- and octogenarians.

The brain, like every other part of the body, changes with age, and

those changes can impede clear thinking and memory. Yet many older

people seem to remain sharp as a tack well into their 80s and beyond.

Although their pace may have slowed, they continue to work, travel,

attend plays and concerts, play cards and board games, study foreign

languages, design buildings, work with computers, write books, do

puzzles, knit or perform other mentally challenging tasks that can

befuddle people much younger.

But when these sharp old folks die, autopsy studies often reveal

extensive brain abnormalities like those in patients with Alzheimer's.

Dr. Nikolaos Scarmeas and Yaakov Stern at Columbia University Medical

Center recall that in 1988, a study of " cognitively normal elderly

women " showed that they had " advanced Alzheimer's disease pathology in

their brains at death. " Later studies indicated that up to two-thirds of

people with autopsy findings of Alzheimer's disease were cognitively

intact when they died.

" Something must account for the disjunction between the degree of brain

damage and its outcome, " the Columbia scientists deduced. And that

something, they and others suggest, is " cognitive reserve. "

Cognitive reserve, in this theory, refers to the brain's ability to

develop and maintain extra neurons and connections between them via

axons and dendrites. Later in life, these connections may help

compensate for the rise in dementia-related brain pathology that

accompanies normal aging.

Exercise: Mental ...

As Cathryn Jakobson Ramin relates in her new book, " Carved in Sand: When

Attention Fails and Memory Fades in Midlife " (Harper), the brains

of animals exposed to greater physical and mental stimulation appear to

have a greater number of healthy nerve cells and connections between

them. Scientists theorize that this excess of working neurons and

interconnections compensates for damaged ones to ward off dementia.

Observing this, Dr. Stern, a neuropsychologist, and others set out to

determine how people can develop cognitive reserve. They have learned

thus far that there is no " quick fix " for the aging brain, and little

evidence that any one supplement or program or piece of equipment can

protect or enhance brain function --- advertisements for products like

ginkgo biloba to the contrary.

Nonetheless, well-designed studies suggest several ways to improve the

brain's viability. Though best to start early to build up cognitive

reserve, there is evidence that this account can be replenished even

late in life.

Cognitive reserve is greater in people who complete higher levels of

education. The more intellectual challenges to the brain early in life,

the more neurons and connections the brain is likely to develop and

perhaps maintain into later years. Several studies of normal aging have

found that higher levels of educational attainment were associated with

slower cognitive and functional decline.

Dr. Scarmeas and Dr. Stern suggest that cognitive reserve probably

reflects an interconnection between genetic intelligence and education,

since more intelligent people are likely to complete higher levels of

education.

But brain stimulation does not have to stop with the diploma.

Better-educated people may go on to choose more intellectually demanding

occupations and pursue brain-stimulating hobbies, resulting in a form of

lifelong learning. In researching her book, Ms. Ramin said she found

that novelty was crucial to providing stimulation for the aging brain.

" If you're doing the same thing over and over again, without introducing

new mental challenges, it won't be beneficial, " she said in an

interview. Thus, as with muscles, it's " use it or lose it. " The brain

requires continued stresses to maintain or enhance its strength.

So if you knit, challenge yourself with more than simply stitched

scarves. Try a complicated pattern or garment. Listening to opera is

lovely, but learning the libretto (available in most libraries)

stimulates more neurons. In my 60s I took up knitting and crocheting and

am now learning Spanish. My husband is a fanatical puzzle-doer who

recently added Sudoku to the crosswords and double-crostics he carries

around with him.

In 2001, Dr. Scarmeas published a long-term study of cognitively healthy

elderly New Yorkers. On average, those who pursued the most leisure

activities of an intellectual or social nature had a 38 percent lower

risk of developing dementia. The more activities, the lower the risk.

Long-term studies in other countries, including Sweden and China, have

also found that continued social interactions helped protect against

dementia. The more extensive an older person's social network, the

better the brain is likely to work, the research suggests. Especially

helpful are productive or mentally stimulating activities pursued with

other people, like community gardening, taking classes, volunteering or

participating in a play-reading group.

.... and Physical

Perhaps the most direct route to a fit mind is through a fit body. As

Aamodt, editor of Nature Neuroscience, and Sam Wang, a

neuroscientist at Princeton University, recently stated on The New York

Times's Op-Ed page, physical exercise " improves what scientists call

'executive function,' the set of abilities that allows you to select

behavior that's appropriate to the situation, inhibit inappropriate

behavior and focus on the job at hand in spite of distractions.

Executive function includes basic functions like processing speed,

response speed and working memory, the type used to remember a house

number while walking from the car to a party. "

Although executive function typically declines with advancing years,

" elderly people who have been athletic all their lives have much better

executive function than sedentary people of the same age, " Dr. Aamodt

and Dr. Wang reported.

And not just because cognitively healthy people tend to be more active.

When inactive people in their 70s get more exercise, executive function

improves, an analysis of 18 studies showed. Just walking fast for 30 to

60 minutes several times a week can help. And compared with those who

are sedentary, people who exercise regularly in midlife are one-third as

likely to develop Alzheimer's in their 70s. Even those who start

exercising in their 60s cut their risk of dementia in half.

Exercise may help by improving blood flow (and hence oxygen and

nutrients) to the brain, reducing the risk of ministrokes and clogged

blood vessels, and stimulating growth factors that promote the formation

of new neurons and neuronal connections.

This is the second of two columns on memory. The first dealt with tips

for the forgetful.

Correction: December 12, 2007

The Personal Health column on Tuesday, about the mental reserves that

might help ward off symptoms of dementia, misstated the name of the

medical center with which two researchers who study the issue are

affiliated. Dr. Nikolaos Scarmeas and Yaakov Stern are at Columbia

University Medical Center, not Columbia-Presbyterian Medical Center.

(The name was changed in 2003.)

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