MONDAY, Feb. 6 (HealthDay News) -- New guidelines for diagnosing
the mental decline that can come with several diseases of aging may
create confusion among doctors and patients about who has early
Alzheimer's disease and who simply has mild cognitive impairment, a
new report warns.
Mild cognitive impairment (MCI) is a mental decline in its
earliest stages that's not a normal part of aging. Under previous
guidelines, a patient was considered to have MCI if he or she had
marked, but mild, memory problems but was otherwise functioning
normally, explained Dr. John Morris, director of the Alzheimer's
Disease Research Center at Washington University School of Medicine
in St. Louis.
Recently, the U.S. National Institute on Aging and the
Alzheimer's Association convened a work group to update criteria
for MCI. Their revised guidelines cast a wider net for what
qualifies. "As MCI was studied further, it was found that people
with MCI often had other impairments in reasoning, visual-spatial
skills and attention," Morris said.
Under the new guidelines, people with MCI can have also have
problems doing daily activities, such as driving without getting
disoriented, remembering to pay bills and paying the proper amount,
and cooking safely. People can have MCI even if they depend on aids
or assistance to complete those tasks.
Previously, what distinguished MCI from dementia was that
ability to function, but the new guidelines blur the distinction,
"Now, there is no distinguishing line between mild cognitive impairment and mild Alzheimer's disease dementia," said Morris, who lays out his argument in an analysis published online Feb. 6 in the Archives of Neurology. "Broadening the criteria for MCI overlaps so much with the diagnosis of very mild Alzheimer's disease that physicians won't know whether to call it very mild Alzheimer's or MCI. It adds confusion to the field."
Morris' study included more than 17,500 people with a mean age
of 75 who had either normal memory and thinking skills, MCI or
Alzheimer's disease dementia.
He concluded that 99.8 percent of patients currently diagnosed
with "very mild" Alzheimer's dementia and just under 93 percent of
those diagnosed with "mild" Alzheimer's dementia could be
reclassified as having MCI, based on the revised criteria.
Some 5.4 million Americans have Alzheimer's, according to the
While MCI can be a first sign of the Alzheimer's, it's not
necessarily so. Other causes of MCI can include medications, stroke
or depression, Morris explained.
Diagnosing Alzheimer's disease is typically done through a
clinical examination with a neurologist. Neuroimaging tests are
conducted, to rule out other conditions that might have caused the
mental decline, such as a stroke or brain tumor.
Other means of diagnosing Alzheimer's include a spinal tap that
looks for certain biomarkers in the spinal fluid or specialized
MRIs that can detect amyloid protein, which is associated with
Alzheimer's. However, these are not typically available outside of
large metropolitan hospitals or as part of medical studies.
Dr. William Thies, chief medical and scientific officer for the
Alzheimer's Association, said researchers now understand that
Alzheimer's is a continuum of changes in the brain that begin
years, and possibly decades, before the first MCI symptoms are
noticed. Alzheimer's itself, Thies said, represents "the very last,
devastating changes of the disease."
"You can do a lot of damage to the brain before it will not do all the functions it's supposed to do," Thies said. "There is a period of time when you will have silent changes in your brain structure and function, a pre-symptomatic period when the changes have already begun."
Because Alzheimer's is a continuum, that means that drawing a
line between MCI and Alzheimer's is, by definition, "artificial,"
"We recognize those lines are artificial, and at the moment because the criteria are relatively new, they remain somewhat fuzzy," Thies said. "This is an area where we will have continued discussion over the next few years to establish consistently where to categorize folks."
When Alzheimer's is believed to be the underlying cause of MCI,
physicians can offer up a diagnosis of "MCI due to AD [Alzheimer's
disease]," Morris said.
Even though the diagnosis of Alzheimer's is more devastating
than MCI, it's important for patients and their families to hear
the truth, so that they can come to terms with the diagnosis and
make the necessary plans, Morris said.
"When we think the MCI is caused by underlying Alzheimer's disease, we should go ahead and call it very early Alzheimer's," Morris said. "It's artificial to call it MCI."
According to background information in the article, 30 percent
to 60 percent of doctors conceal an Alzheimer's disease diagnosis
because of causing distress to the family and the patient, even
though 94 percent of the same doctors would reveal a diagnosis of
Dr. Gayatri Devi, an attending neurologist at Lenox Hill
Hospital in New York City, said that as a result of the new
criteria, "large numbers of patients will be classified as having
mild cognitive impairment when in fact they're suffering from
"This complicates research in the area, and confuses patients and families, not to mention physicians, who've relied on functional independence as the demarcation between Alzheimer's disease and MCI," Devi said.
National Institute on Aging has more on Alzheimer's.