The findings also offer some useful information for the average
person, according to Wilson.
"If you're aware enough to be worried about your memory, you
probably don't have dementia," he said. Nor is it clear that you
ever will, since memory issues do not mean a person is doomed to
develop Alzheimer's or other forms of dementia.
The findings, published in the Aug. 26 issue of Neurology, are
based on nearly 2,100 older adults who were assessed annually
for over a decade.
They took standard tests of memory and thinking skills, and gave
their own opinions of their mental sharpness, answering
questions such as, "How often do you have trouble remembering
things?"
Overall, 239 people were diagnosed with dementia during the
study period. Wilson's team found that their awareness of their
own memory problems began to fade two to three years before the
onset of dementia, on average.
Defining the onset of dementia is not clear-cut, according to
Wilson. But, he said, it is based on more than just memory loss:
People with dementia also typically have problems with language,
concentration and planning, and may often become confused about
the day or month, or where they are.
The new findings give support to what doctors and researchers
have believed to be true, said David Morgan, director of the
Signature Program in Neuroscience at the University of South
Florida College of Medicine, in Tampa.
"This is something we've been aware of," said Morgan, who is
also a spokesperson for the American Federation for Aging
Research. "There's a saying in the field that if you know you
have memory problems, then you don't have dementia."
But this study, he said, offers a "rigorous analysis" of the
issue.
The findings have some clear implications, according to Morgan.
"If you don't think you have a problem, you're unlikely to seek
help," he said. "So, it's important for relatives to be
sensitive to signs of dementia."
Wilson agreed. If mom sometimes misplaces her keys, there's no
need to rush to the doctor, he said.
But if she's showing a pattern of memory lapses -- and seems
unaware of it -- that would be a red flag, he said.
Morgan noted that under the recent health care law, Medicare
must now cover screening tests for cognitive impairment.
"But in practice," he said, "that may amount to the doctor
asking, 'How's your memory?' Obviously, that's inadequate."
There is no cure for dementia, but detecting it in earlier
stages is still important, Morgan said.
There are some medications that can lessen or stabilize
symptoms, and people with milder impairment may be able to
enroll in a clinical trial testing new therapies, he pointed
out.
Earlier detection also allows people to plan for the future
while they still have the capacity to make decisions, Morgan
said.