How would you react if, all of a sudden, your parent or other relative or friend didn’t know who you were?

Nothing prepared Mary for the sudden loss of recognition by her mother. One day her mom seemed the same as ever, an elderly person and sometimes forgetful. Her children went along with it, compensating and rationalizing. They helped her remember the word she forgot; they found her keys; they reminded her of the grandchildren’s names. They talked about this forgetfulness as “old age,” but it truly was memory loss. Mary’s daughters didn’t worry too much, because a lot of older people they knew were in similar condition.

Then one day, when Mary rang her mother’s doorbell, the door opened and an elderly woman looked at Mary with a blank expression, even a little suspicious. Mary realized her mother didn’t recognize her. The sad part was that she would never again remember who Mary was.

This situation is more common than you might think.

One day more than 20 years ago, on my way home from work, I stopped to visit a friend. This was a person I had known all my life, but hadn’t seen in about six months. When he opened the door and I greeted him, he couldn’t remember my name. I reminded him who I was and he asked me if I’d like a cold drink. As he opened the refrigerator, I noticed it was stuffed with pieces of paper. There were other unusual signs that things were not right. I didn’t know it then, but this was my first encounter with Alzheimer’s, a disease that affects more and more people each year. In the intervening years, I have seen dozens of friends and several relatives “disappear” because of Alzheimer’s.

Today, many middle-aged and older people are very familiar with Alzheimer’s. Having learned more about it, they are scrambling for information on not just dealing with Alzheimer’s, but how to prevent it from happening to them.

What steps can we take to prevent memory loss as we get older? How can we lower our risk of developing Alzheimer’s disease?

Dr. Lucie Arbuthnot will answer these questions in a lecture entitled “Outwit Memory Loss: Keeping Your Brain Fit After Fifty” on Friday, March 16, from 3:30-5 p.m. at the University of Southern Maine in Portland. The lecture will present recent scientific research on staying mentally sharp as we age. It is free and open to the public.

“Simple lifestyle choices are our first line of defense,” she said, pointing to the benefits of staying physically and mentally active, and eating a healthy diet. She also emphasized the need to monitor certain medical conditions that may influence cognition, such as cholesterol and blood-pressure levels.

In addition, Arbuthnot’s talk will clarify how taking steps to reduce the risk of memory loss and Alzheimer’s disease may even lower the risk of other major chronic diseases, such heart disease, stroke, diabetes, and some forms of cancer.

“It’s really a win-win approach,” she said.

Despite the serious topic, Arbuthnot’s message is positive and upbeat.

“Lucie’s talks are always a big hit with our audiences,” said Phyllis Cohn, associate state director of AARP Maine, one of the sponsors of the lecture. “She is a dynamic speaker and a wonderful motivator.”

Other sponsors include the Alzheimer’s Association, Maine Chapter; the Southern Maine Agency on Aging; and the Maine Centers for Women, Work & Community.

The talk will be held in the Talbot Lecture Hall of the Luther Bonney building. It is wheelchair accessible. If USM is closed due to weather, the lecture will be held a week later, on Friday, March 23.