Human Body: Keeping Good Brains from Going Bad

(Trying to find solutions to two life-robbing diseases: Alzheimer's and Parkinson's)

The Quest to Beat Aging

It’s hard to believe now, but 30 years ago the average layman and the average doctor thought that “senility” was the result of either normal aging or hardening of the arteries. “What do you expect from an old person?” people would say.

Mercifully, science has enlightened this rather Dickensian view. Today we may be close to understanding what causes the major neurological diseases of old age, which ravage mental and physical function—the very stuff of life—and in their extreme form can kill.

That does not mean we’ve found cures for the four million Americans suffering from Alzheimer’s disease and the one million with Parkinson’s. The numbers could swell fourfold by 2040 as baby boomers reach old age. Legions of us worship at the temples of Physical Fitness and Cooking Light, in an attempt to ensure strong bodies at retirement, but what can we do when it’s our brains that betray us?

The silent siege of Alzheimer’s causes a relentless deterioration of memory and bodily control. The disease is a formidable foe. Most Alzheimer’s patients are in their 70s and beyond, and those who survive into its final stages lose the ability to speak, walk, even lift their head as their brain slowly shuts down.

Given how debilitating the physical throes are, it is confounding that the disease first appears years earlier as mental troubles such as chronic forgetfulness and difficulty handling routine chores. Indeed, the onset is so elusive that doctors are only now determining where normal aging of the brain stops and Alzheimer’s begins.

The borderland is a state called mild cognitive impairment (MCI). Individuals with MCI aren’t demented, but they do perform worse than their peers on memory tests. They sense they are forgetful, and somebody close to them has probably noticed it, too. Otherwise, they do quite well, although demanding tasks such as mastering new technology may prove challenging.

Someday a combination of memory tests and magnetic resonance imaging may offer early warnings to those destined for Alzheimer’s—valuable information if drugs are developed that can prevent the disease or stop its progression. Elderly people who feel forgetful but perform well in cognitive tests—Petersen refers to them affectionately as “the worried well”—develop Alzheimer’s at much lower rates, about 12 percent over four years in Reisberg’s study. All that’s necessary, Reisberg says, is “to reassure them.”

Older people these days do seem quick to diagnose themselves or loved ones as having Alzheimer’s when they are just experiencing simple forgetfulness. The knee-jerk response is in part the result of stepped-up media coverage.

So what should set off alarms? Failure to remember important items with increasing frequency, Petersen says— “things that you would have remembered without question six months ago”—especially if other people also say they see a change in you. “It’s not that you misplaced your keys,” adds Richard Mohs of the Mount Sinai School of Medicine. “It’s that you can’t figure out what you would do to get them back.”

Mohs points out that everybody gets more forgetful with age. “The rate at which people can put new information into memory does slow down. When they say, ‘I forget more,’ it’s usually that they just didn’t learn it quite as well.” Elderly people can boost memory by taking extra time and care to learn new information.

Some indications of hope

Once Alzheimer’s is diagnosed, families can brace for the future, but the medical profession finds itself at something of a loss. Neurotransmitter- boosting drugs such as Aricept help about 50 to 70 percent of patients, according to Peter Rabins of the Johns Hopkins School of Medicine, but their efforts are modest. Rabins says, “I ask families to think back to what the person was able to do seven or eight months ago; that’s an average improvement.”

Although this reprieve is precious, it’s unclear if any improvement can last longer than a few months. For now, managing Alzheimer’s consists mainly of emotional and practical support, plus strategies to help patients retain skills and live a full life.

An ounce of prevention may be worth a pound of cure. Various studies, including a landmark University of Kentucky study of elderly nuns belonging to the order of the School Sisters of Notre Dame, suggest that the brain’s ability to resist dementia is greater if it has been mentally stimulated throughout life. “If you don’t use it, you lose it,” exhorts the University of Kentucky’s William Markesbery, part neuropathologist, part personal trainer.

Richard Mayeux, director of the Taub Institute on Alzheimer’s Disease and the Aging Brain at Columbia University, also finds that people with complex jobs have reduced risk of Alzheimer’s no matter their education—suggesting again that intellectual challenge throughout life is important. Mohs of Mount Sinai suggests exercising the brain by reading, taking classes, and joining intellectually engaging clubs.

Caring for the body is a good idea, too. People who are aerobically fit tend to suffer less cognitive decline with normal aging. Intriguingly, when Fred H. Gage of the Salk Institute for Biological Studies in La Jolla, Calif., allowed mice to run at will—about five kilometers a day on average—they generated many new neurons in their hippocampi compared with their cage-potato counterparts. Others have found that prolonged stress actually leads to hippocampal atrophy.

The search for ways to slow or prevent Alzheimer’s is widening. The nuns, as well as identical twins and a group of women in upper Manhattan, are the primary test subjects. Many of the School Sisters nuns donate their brains to the University of Kentucky’s Sanders- Brown Center on Aging; Markesbery, the center’s director, has examined them and others. One remarkable thing he sees are organs rife with the lesions characteristic of Alzheimer’s—from individuals who were not demented.

Perhaps these brains had something extra in reserve, or maybe they avoided stroke. Dementia from vascular disease alone is fairly uncommon in the U.S.; but among nuns with the brain lesions of Alzheimer’s, those who also had tiny strokes were more likely to be demented. To lessen the risk of stroke, Markesbery advises people to eat right, exercise, not smoke, and keep blood pressure and diabetes under control—good advice in any case.

—Compiled from
"Thwarting Major Killers/Preventing Good Brains from Going Bad; The Quest to Beat Aging";
Scientific American Presents; by Mia Schmiedeskamp.