Memory

Issue date:
May 16-18, 1997

Are you losing your mind?

Around 40, people begin having trouble staying focused and retaining information. For 78 million baby boomers hitting the "memory barrier," it's a big fear.

Related story: Quiz: Test your memory. This quick quiz can help you detect the signs of memory impairment

Today's 40-year-old is especially susceptible to memory loss because of the brain power used in "multi-tasking" -- juggling work, kids, parents, technology.

You're at a party, and you see someone across the room you know you've met but you can't recall her name. Or you're writing a shopping list when the phone rings, and then you can't remember the one item you really wanted. Memories may be beautiful, yet we might simply forget -- not because we choose to, but because we're older.

Forgetfulness, clinically called "age-associated memory impairment," can make people worry they are losing their mind or are in the early stages of Alzheimer's. It often first appears as difficulty recalling names or doing simultaneous activities, such as typing notes into a computer while talking on the phone. It can begin in the 30s but usually becomes noticeable in the mid-40s to early 50s, making it one of the most common problems of midlife.

That's bad news for the 78 million-member baby boom, the leading edge of which hit 50 last year. To the generation that came of age in the fitness boom and wholeheartedly pursues youthfulness, even a slight decrease in memory seems like a tragedy.

But just as boomers are credited with sending the stock market to record heights as they prepare financially for retirement, their interest in staying mentally fit ignited what Dr. Paul Costa, chief of the Personality and Cognition lab at the National Institute of Aging, calls "a proliferation of research" into why memory fails -- and what can be done about it.

What we know about memory

Researchers don't yet know conclusively why almost everyone experiences some memory loss with aging. Brain cells "become less efficient for reasons that aren't explicitly clear," says Dr. Murray Grossman, director of the cognitive neurology section at the University of Pennsylvania hospital. "It could be shrinkage of the cells, or neurons, or there may be some dropout [cells shrink until they are so small they "die"], just the way our body has other cells that get less effective as we get older." Other theories include an age-induced decline in neurotransmitters -- chemicals like dopamine that help brain cells communicate -- or a degeneration of brain tissue caused by stress-released chemicals such as cortisol. The frontal lobes, which are particularly important in memory, are more susceptible to the loss of efficiency.

What researchers have established is that normal memory loss differs significantly from dementia. In normal aging, individuals may have a "tip-of-the-tongue" memory loss for words that haven't been used in a while, says Pomona College psychology professor Deborah Burke. "So if you haven't seen your niece in six months, or if it's simply an acquaintance, you may have problems remembering their name," she says. "With Alzheimer's, people lose names of common objects, like 'spoon' or 'plant.' " Perhaps 16 million people will develop Alzheimer's in the next 25 years, but memory loss is not the first sign of Alzheimer's.

Researchers also have distinguished between types of memory -- and determined that not all memory functions are affected by aging. Long-term memory seems to have little age impairment; short-term memory is most affected. Short-term memory includes "working memory" (retaining information several seconds while doing more than one activity, such as opening mail while talking on the phone) and "anterograde" memory (learning something new, like a list of names or groceries). Long-term memory includes "autobiographical" memory (recalling events in your life) and "semantic" memory (vocabulary).

Researchers like the NIA's Costa hasten to point out that midlife memory impairment is small, and the most dramatic decline in memory doesn't occur until around age 70. "If you give someone in their 40s a list of 16 words to be remembered, they will recall anywhere from 10 to 16," he says. "A 70-year-old might recall five or six." The decline, he adds, is incremental and highly individual.

What appears to be memory loss could be due to another condition altogether. Depression can affect short-term memory. Medications, including drugs for high blood pressure and anxiety, tranquilizers, antidepressants and even insulin, may have side effects that seem to be short-term memory loss. Regular marijuana or alcohol use can lead to memory loss.

Meanwhile, Dharma Singh Khalsa, a Tucson, Ariz., physician who is the author of the new book Brain Longevity, believes boomers are especially susceptible to age-associated memory loss because of brain overload created by what he calls "multi-tasking stress." At 51, he says, he's the perfect example, with teenagers, a previous marriage and a 90-year-old mother who requires caretaking. Add to that modern pressures and insecurities and the pace of technology, and, he says, "Even if we are adapting to it all, this is the stress that produces the cortisol overload that results in poor memory."

Research developments

Across the country, scientists are working to pinpoint causes by using: