What’s the difference between normal brain aging and cognitive decline? - The Washington Post

Many people worry they are developing serious cognitive deficits when these are in fact only minor and within the bounds of normal aging. Most people who fear Alzheimer’s do not appear to get it. Doctors routinely reassure worried patients: “Forgetting where you left your keys is normal. Finding them in your refrigerator and not knowing what they are for indicates Alzheimer’s.”

As our bodies age, so do our brains. Like many other sets of symptoms, cognitive impairments fall across a wide spectrum, from minor “senior moments” to more severe dementia, caused by Alzheimer’s, strokes and various other conditions and resulting in the inability to work, drive or live on one’s own.

What is normal cognitive aging?

Normal age-related cognitive decline commonly starts at about age 40, but it consists of several distinct mental processes that shift at very different rates.

The changes can affect three areas of cognition:

• Processing speed: Visual processing speed is how quickly someone can process visual information, such as letters and numbers. Cognitive processing speed is how long it takes you to process information, think about it and respond.
• “Crystallized” intelligence: This includes the vocabulary, knowledge and skills you have acquired during your life through education and experience. (The good news is that this tends to get better over time.)
• Memory: This is the brain’s ability to recollect from the past and learn new information now.

In normal brain aging, crystallized intelligence remains relatively intact. But our ability to process information slows down. Speed drops by about 20 percent when we are 40 and may naturally decline 40 to 60 percent by the time we are 80.

As we get older, our memory diminishes as well, though people vary widely in this, and we may each also fluctuate a bit day to day.

What’s important to remember is this: While about 40 percent of us over 65 have occasional memory impairment associated with age, most people do not go on to develop dementia. We may sometimes take a bit longer to retrieve certain words, but usually we eventually recall them. We may forget someone’s name, but we still clearly recognize them if we see them.

Forgetting a word, in itself, is generally normal. It doesn’t disrupt our life or our ability to function or necessarily indicate impending dementia. Importantly, we can still reason, solve problems and make key decisions.

When memory slips are signs of mild cognitive impairment

Several years ago, researchers established the term “mild cognitive impairment” (MCI) to describe a transitional state between such normal cognitive aging and dementia that some people develop.

About 16 to 20 percent of Americans over 60 have mild cognitive impairment, which represents significantly more than the normal aging process. About 10 to 20 percent of people with MCI develop dementia each year.

One way to check for MCI is to take a simple free self-administered online test such as the Self-Administered Gerocognitive Examination (SAGE), developed by Ohio State University.

The test requires only a few minutes and asks, for example, the names of several objects and animals, the number of nickels in a certain amount of money, and the quantity of change you get from $20 if you buy an item for a certain price.

The online test site won’t give you your results — you will need to discuss it with your primary care doctor to be scored. But you will probably have a pretty good idea how you performed. If you are now reading and fully understanding these sentences, the odds are very good that you will “ace” the brief exam and see that you have answered all the questions correctly.

No test is perfect, but this one reassures many people that momentarily forgetting someone’s name does not indicate mild cognitive impairment.

How you can protect yourself against cognitive decline

We can protect ourselves against cognitive decline in several ways:

Exercise and physical activity: Aerobic exercise, which increases your heart rate, for instance through jogging, cycling or speed walking, and strengthening muscles by lifting weights all aid our brains.

Treating blood pressure and other medical problems: All of us should have regular medical checkups to make sure we are staying as healthy as possible and to get any high blood pressure, high cholesterol or other risky medical problems addressed.

Brain stimulation: Certain activities, especially those that involve learning new skills and/or communicating and interacting with others, can help. This includes learning new board games, such as mah-jongg or go, or playing computerized cognitive training games that require decision-making. Crossword puzzles increase verbal fluency. Specially designed video games and virtual reality programs may be beneficial, too, though studies of these are just beginning and not yet fully conclusive.

Education: Early and later education, too, both protect against subsequent cognitive slippage.

Purpose: Having a sense of purpose, often derived from religion, spirituality or beliefs in nature or a “higher power,” can assist as well.

Social activities: Interacting and communicating with others, such as through book groups, religious or other organizations, reduces declines in memory and thinking.

Mental health: Depression can worsen cognition, so getting treatment for mental health problems can be helpful.

Avoiding alcohol and recreational drugs: Over time, alcohol and several other recreational drugs impair our thinking, too.

People experiencing significant cognitive impairments should consult a doctor, since these symptoms could result from underlying but treatable medical conditions, including certain infections and cancers.

In addition, several doctors and professors I know tell close colleagues, “Let me know if you see me slipping too much cognitively,” since we ourselves may not always be aware of these alterations.

These topics are not easy. I admit that when I forget where I put my phone, it troubles me. But I found the SAGE test easy, and I remind myself that at 66, I’m not as young as I was and some memory slips are perfectly normal. In addition, I try to appreciate all that I do know, exercise, take my blood pressure medication, stay healthy and keep my mind active. Activities such as these will benefit not only your thinking, but your mood, heart and body as well.

Robert Klitzman is a psychiatrist and the director of the masters of bioethics program at Columbia University. He is the author, most recently, of “Doctor, Will You Pray for Me?: Medicine, Chaplains and Healing the Whole Person.”