by Martha Weinman Lear.

Grand Central Publishing. 247 pages. $22.99.

BY JEANNE NICHOLSON
Special to the Journal

If you are one of the millions complaining more about remembering less as they grow older, Where Did I Leave My Glasses? The What, When and Why of Normal Memory Loss will answer a multitude of questions. Holding onto one’s intellect is a major issue for baby boomers and their elders.

Memory problems do not mean you have Alzheimer’s or dementia cautions one of the many doctors interviewed by author Martha Weinman Lear. Noticeable memory loss is normal after 50 years; your ability to hold on to new information is just not as good as it used to be. “Normal memory loss happens because brains start to shrink, blood flow starts to ebb, and chemical neurotransmitters start to do less of whatever it is that they do,” Lear writes in her breezy, entertaining style.

What are the warning signs of serious problems? People withdraw; they stop joking about their memories and start trying to hide their confusion, or they stop talking simply because they are afraid of using the wrong word or saying something stupid, according to one New York neurologist. Some develop the “cocktail personality” and “learn to talk for hours without having to give any information.” Clever dogs.

When there is serious worry, “the blame game” starts, “and then morphs from ‘I can’t remember where I left my keys’ into ‘Who moved my keys?’ and possibly, ‘Why did you take my keys?’ which pretty much encapsulates the distinctions among normal memory loss, mild cognitive impairment, and dementia,” writes Lear.

Then there are those born with “a neurological leg up, with more intrinsic skills for remembering, (known as cognitive reserve). Some people may have genes that provide an extra margin of protection against dementia” (like a well-managed hedge fund), according to one study of seniors whose memories are intact into their 80s and 90s.

A research team is now designing a study to learn more about how cognitive reserve works and how it can be enhanced. Brain scans show some people use different neural pathways than others to solve the same problem. And there’s more about new research in the chapter on diet and memory.

What is a brain-healthy diet? A heart-healthy diet is the answer. Brain food also includes various ginkgo products, which scored an A for the treatment of Alzheimer’s disease and vascular dementia, but only a C as a memory booster for healthy people.

A Harvard report suggests that we all do our homework to know what we’re getting in products and cites www.clinicaltrials.gov as one good source for products that have been tested and how they scored. WHERE DID I LEAVE MY GLASSES? The What, When and Why of Normal Memory Loss,