if your mother forgets where she parked her car at the mall, blanks on her grandson's name or loses the check to the electric company, don't worry — such memory problems are probably normal.
If she doesn't remember ever going to the mall, fails to recognize her grandson and can no longer figure out how to write a check, she probably has Alzheimer's disease or some other form of dementia.
But what if she is somewhere in between? What if she feels her memory problems are rapidly getting worse, but she can still read, write, pay bills and perform other routine tasks without a problem?
Then she may have mild cognitive impairment (MCI), a condition some believe could affect up to a third of the 35 million Americans over the age of 65.
Considered a discrete disorder when first identified just a few years ago, MCI is now recognized as a frequent prelude to Alzheimer's — a transitional phase from normal brain aging to the disease itself. Almost half the people diagnosed with MCI today will have developed Alzheimer's within five years.
Diagnosing MCI requires verbal tests to evaluate memory, judgment and other mental abilities. Researchers are also investigating the use of brain scans to distinguish MCI from normal age-related memory problems on one end and Alzheimer's disease on the other.
But MCI isn't necessarily early Alzheimer's. Instead, an MCI diagnosis may serve as a valuable early warning for many treatable problems, such as stress, depression, heart disease, hearing loss, nutritional deficiencies and inactivity.
“My philosophy is that when people get into their 80s, they're entitled to have some memory problems,” says Majid Fotuhi, M.D., a neurologist specializing in memory disorders at Sinai Hospital of Baltimore. “People at 85 won't be able to remember as well as they could 20 years earlier. However, memory problems don't equal MCI or dementia. A person who hasn't had enough sleep or is depressed or drinks too much or lives an isolated lifestyle — these are common causes of memory problems.”
Taking the Alzheimer's drug donepezil (Aricept) may help a person with MCI, he says. A recent study found that donepezil reduced the risk of people with MCI developing Alzheimer's for up to 12 months — although, by the end of the three-year trial, there was no difference between those who had and hadn't taken the drug. Like the other four drugs approved for Alzheimer's symptoms, donepezil does not stop or slow the progression of the underlying disease itself, notes Ronald C. Petersen, M.D., principal investigator of that landmark MCI study and director of the Alzheimer's Disease Research Center at the Mayo Clinic.
“There are no drugs approved for MCI,” says Petersen, who pioneered the concept of the condition and authored the definitive book Mild Cognitive Impairment: Aging to Alzheimer's Disease. “Instead, we recommend education. You're still functional. Now may be the time to deal with your finances, your retirement plans, maybe make some travel plans.”
Addressing only the memory problems of older people isn't enough, Dr. Fotuhi says. He always looks for treatable causes of memory problems, such as high blood pressure, high cholesterol and diabetes. He checks for thyroid problems and vitamin B-12 deficiency. He asks about the patient's medications and possible sources of distress or depression.
“A common mistake among physicians is to assume an older person who has declined will soon develop dementia,” he says. “I've seen plenty of people with memory problems who have turned around. Finding MCI is an opportunity for intervention, and it's better to intervene early than to wait until there are symptoms of dementia.”
A powerful deterrent to cognitive decline appears to be vigorous mental activity, both earlier in life and in old age. A long-term study conducted by David Snowdon, Ph.D., found many nuns who remained lucid and vigorous into extreme old age even though their brains were riddled with the diseased nerve cells found in Alzheimer's. In his 2001 book Aging with Grace, Dr. Snowdon, a professor of neurology at the University of Kentucky, concludes Alzheimer's must be a disease “that evolves over decades and interacts with many other factors.”
What other factors? Diet, exercise and genetics undoubtedly play a role, but mental activity emerges again and again as one of the strongest protectors of the aging brain.
David A. Bennett, M.D., director of the Rush Alzheimer's Disease Center in Chicago, has been conducting the Religious Orders Study involving more than 1,000 nuns, priests and brothers. The results persuade him that this advice applies to the brain: “use it or lose it.”
Dr. Bennett has found that mental activity reduces the risk of Alzheimer's. This confirms studies demonstrating that people with more education have greater resistance to cognitive decline. Doctors also recommend physical activity since a growing body of research shows that what's good for the heart is good for the brain.
People who have MCI would do well to “remain cognitively and physically and socially active,” Dr. Bennett says. “We're not in a position at this time to recommend one activity over another. As far as we can tell, what matters is the variety — doing a bunch of different things — because you're stimulating different parts of your brain.”
As new treatments for Alzheimer's and other dementias become available, MCI might alert doctors early enough to disrupt the disease before it does permanent damage. “The most promising therapeutic interventions would halt the degenerative process rather than reverse it,” says Adam Gazzaley, M.D., assistant professor of neurology at the University of California–San Francisco. “That's why it is so important to recognize signs of dementia early.”
Defining MCI has proved elusive, but physicians and researchers agree that clarifying the diagnosis will help detect Alzheimer's at ever-earlier stages as well as conditions that may be treatable. The ability to detect subtle memory problems can help patients today. But more than that, it promises to guide the development of new treatments for memory loss and Alzheimer's disease itself.