About 1 in 7 people age 60 or older have a brain condition that may be an early sign of Alzheimer's disease.
The condition, called mild cognitive impairment, occupies a gray zone between normal aging of the brain and dementia. And most people know almost nothing about it.
A national survey found that 82% of Americans are unfamiliar with the condition or know very little about it. More than half thought the symptoms sounded like "normal aging," according to the survey, which was part of a special report released this week by the Alzheimer's Association.
"Mild cognitive impairment is often confused with normal aging because it is very subtle," says Maria Carrillo, chief science officer of the Alzheimer's Association. Symptoms include "forgetting people's names, forgetting perhaps that you've said something already, forgetting a story, forgetting words," she says.
The condition, which affects about 10 million people in the U.S., is defined as changes in memory and thinking that are noticeable to the affected person and those around them but not serious enough to interfere with the individual's everyday activities.
That makes it tricky to diagnose, says Dr. Pierre Tariot, director of the Banner Alzheimer's Institute in Phoenix.
So after talking to a patient, Tariot often asks if he can speak with the person's spouse or a close family member.
A patient's wife, for example, might notice that her husband is still managing to keep his appointments, Tariot says, but then she adds: "But a year ago, he had it all locked and loaded in his brain. And now, unless he writes it down 12 times and then asks me to double-check, he's not going to get there."
Is that mild cognitive impairment or dementia? Tariot says it would be a tough call.
Diagnosis is key — but not everyone wants one
A diagnosis of mild cognitive impairment requires at least one visit to a doctor, Carrillo says. But that won't happen if an affected person doesn't recognize the symptoms or doesn't want to get a life-changing diagnosis.
In the survey, just 40% of respondents said they would see a doctor right away if they experienced symptoms associated with mild cognitive impairment. The rest said they would wait or not see a doctor at all.
Reasons for avoiding the doctor included fear of receiving an incorrect diagnosis (28%), learning they have a serious problem (27%), fear of receiving an unnecessary treatment (26%) and believing symptoms will resolve in time (23%).
But if people avoid seeing a doctor for their symptoms, "they're not going to open the door to finding out what the underlying cause is," Carrillo says.
That's important, because the symptoms of mild cognitive impairment can be caused by lots of factors other than Alzheimer's disease.
"Maybe somebody is tired. Maybe somebody is not sleeping well. Maybe somebody is taking some medications that make them a little groggy," Carrillo says.
Also, many of the underlying causes of memory and thinking problems can be remedied.
Sleep apnea can be treated. So can depression. "If there's a vitamin B12 deficiency, it does actually mimic mild cognitive impairment or even early Alzheimer's dementia," Carrillo says. "And that can be solved with vitamin B12 injections."
If those causes have been ruled out, a patient may be referred to a specialist or subspecialist.
"At a specialty clinic, we absolutely can detect whether mild cognitive impairment is due to Alzheimer's or not," Carrillo says.
About a third of patients with the condition will be diagnosed with Alzheimer's within five years, she says.
But long before then, tests can reveal whether mild cognitive impairment is the result of disease processes in the brain that are associated with Alzheimer's.
"We're rapidly zooming into an era where we can use imaging or blood or spinal fluid tests to establish likely causes" of memory and thinking problems, Tariot says.
Those tests can reveal the presence of sticky plaques and tangled fibers in the brain, which are the hallmarks of Alzheimer's.
For Alzheimer's, early diagnosis offers options
When Alzheimer's is the cause of mild cognitive impairment, patients have a growing number of treatment options, Tariot says.
One is Aduhelm, a controversial Alzheimer's drug approved last year by the Food and Drug Administration. The drug has a proven ability to remove sticky plaques from the brain. But it's still unclear whether it can slow memory loss.
Another good option for many patients with mild cognitive impairment is enrolling in a clinical trial of an experimental Alzheimer's drug, Tariot says.
"They're all scientifically sound, ethically sound, approved by the FDA, done under FDA oversight," he says.
Moreover, many drug trials are trying hard to recruit patients in the earliest stages of Alzheimer's, including those with mild cognitive impairment. That's because many scientists believe the best chance to intervene is before the disease has caused significant damage to the brain.
"The earlier you get on treatment, the better," Carrillo says.
And in part because of Aduhelm's approval, drugmakers are now pushing ahead with many other experimental treatments.
"There's a whole wave of other therapies coming forward," Tariot says, "so we'll have many more choices than we have now, and that's great news."
Those choices are badly needed. Projections show that the number of Americans with Alzheimer's disease will rise from about 6.5 million today to more than 12 million by 2050.