April 28--Mary had worked as a nursing executive in South Florida for more than
three decades when she noticed her first memory lapses. She would forget when
reports were due, when staff was scheduled to meet, what her employees had told
her in the hallway. To compensate, she worked longer hours.
Eventually, when her extra efforts didn't work, she went to see Dr. Ranjan
Duara, medical director of the Wein Center for Alzheimer's Disease and Memory
Disorders at Mount Sinai Medical Center in Miami Beach. After a battery of
tests, including an MRI, she received the diagnosis she feared: Alzheimer's
And she hadn't even turned 60.
"I was devastated," she recalls. "I knew what it meant." She had tended to her
father for years after he was diagnosed with AD.
Mary, who asked that her real name not be used, is 61 now and has been retired
for about a year. The initial shock has worn off, replaced by a desire and
determination to travel and enjoy her family as long as possible.
She's grateful that early detection of the devastating disease has helped her
better plan for the future.
"In a way," she says, with a rueful laugh, "it's a blessing to know what you
For people like Mary, relatively new tests -- and those currently in the
research pipeline -- are helpful tools that allow for earlier detection of this
disease, a necessary and important step in developing a treatment plan to slow
its progress. Traditionally, the only way families got confirmation of
Alzheimer's was after the fact: an autopsy revealed the plaques and tangles in
the brain characteristic of the disease. Doctors arrived at a diagnosis after
ruling out other explanations for the memory loss and through extensive
But those telltale plaques and tangles so common in Alzheimer's can start 10 to
20 years before any symptoms appear. Researchers have long sought a way of
detecting those signature markers long before a patient's memory loss is so
severe they can't function. This is particularly important because as the U.S.
population ages, more and more people are expected to be diagnosed with the
More than five million Americans are currently living with Alzheimer's,
according to the Alzheimer's Association, and experts predict that as many as 16
million will have it by 2050. Nearly one in three seniors who die each year has
some form of dementia, including Alzheimer's. In fact, Alzheimer's is the
sixth-leading cause of death overall and the fifth for those 65 and older.
Caring for those with the disease is also costly -- an estimated $203 billion
this year alone. The toll, however, can be measured in more than dollars. The
Alzheimer's Association estimates that 15.4 million relatives and friends
provided 17.5 billion hours of unpaid care valued at $216 billion in 2012, an
equation that only begins to define the demands placed on the families of
Though Alzheimer's is the only top 10 cause of death that has no prevention or
cure, doctors say early detection tests can alleviate some of the inevitable
stress that accompanies not having a diagnosis, or an incomplete one.
Specialists go through a medical workout to determine what is causing a
patient's memory loss. Initial steps include a variety of tests to determine the
extent of that loss and general health, including medical history and figuring
out if any family member has been diagnosed with Alzheimer's or another form of
Standard tests also include measuring reflexes, balance, vision and hearing.
Blood and urine tests may be ordered to rule out other possible causes of
cognitive problems. In addition, patients undergo two to six hours of specific
standardized testing that can measure the ability to solve simple problems as
well as short-term and long-term memory.
"You need a full history to rule out medical and psychiatric conditions that
affect memory," says Dr. Elizabeth Crocco, chief of the division of geriatric
psychiatry inpatient unit at Jackson Memorial Hospital. These include
depression, bipolar disease or schizophrenia. Even anemia, vitamin deficiencies
and too much medication can affect memory.
If these tests point to cognitive impairment, an MRI of the brain is usually
ordered for the patient, says Dr. Clinton Wright, an associate professor of
neurology and the scientific director for the Evelyn F. McKnight Institute at
the University of Miami. Magnetic resonance imaging or Computed Tomography (CT),
another kind of brain imaging scan, can further rule out other causes that may
cause symptoms similar to Alzheimer's, including tumors, strokes, head trauma or
building of fluid in the brain.
These tests do more than that, however. They also can provide information on the
shape, position or volume of brain tissue -- an important piece of the medical
puzzle, because the brains of people with Alzheimer's are different than those
of healthy people. For example, as the disease progresses, the brain and part of
the hippocampus shrinks as nerve cells and their connections die.
"We can be confident [in our diagnosis] about people with a memory disorder in
combination with the tests," says Wright, "but if someone is only worried about
their memory and is not impaired we have very little certainty."
Other tests available or in the research phase include:
A spinal fluid test, obtained through a spinal tap, identifies beta amyloid, a
protein fragment that forms plaques in the brain; tau, a protein that
accumulates when nerve cells and their connections are damaged; and
phosphorylated tau, a protein marker of neurofibrillary tangle burden --one of
the hallmarks of Alzheimer's disease -- in the brain. The presence of these
markers provides a very accurate indication of Alzheimer's. (On the other hand,
if only amyloid is detected without tau doctors can only say that a patient is
"at risk" of getting Alzheimer's.)
Duara of the Wein Center says spinal taps in potential Alzheimer's cases are
rarely used in the United States but are quite common in other countries. "Here
they are not popular because they are considered invasive, costly and
time-consuming. It's not routine," he says.
The spinal fluid test is covered by Medicare and some private insurance
carriers, but should only be done as part of a comprehensive medical exam that
includes a full clinical evaluation.
PET scans can also test for various amyloid deposition as markers of
Alzheimer's. The FDA recently approved a radioactive tracer than can quantify
the amount of amyloid in the brain. Patients with deposits of beta amyloid seen
on these PET scans and dementia are more likely to have Alzheimer's, but there
is still intense debate (and research) about how PET evidence of amyloid brain
deposits can predict who is going to get the disease.
A different type of PET scan can also measure how much glucose is being used by
the brain. (The more active the brain, the more glucose it uses.) So far no PET
scan has been developed to measure tau, the protein that, along with beta
amyloid, is the signature of Alzheimer's.
PET scans are used in distinguishing Alzheimer's from other dementias when the
diagnosis is in question, but because of their high cost, insurance will not
cover them in the diagnosis of Alzheimer's.
Blood tests, as well as urine tests, are being researched around the world in
hopes that one day they will accurately measure the bio-markers of the disease.
All are in the experimental stage. "The dream is that we will one day have blood
tests that detect the markers in the same way we have tests for high cholesterol
that tell us a patient is at risk of heart disease," Duara says.
Though years away, that dream may be getting closer. In March, researchers at
the University of Nottingham told an Alzheimer's conference in the United
Kingdom that they are a decade from developing a test that can detect the
bio-markers found in the disease, including amyloid and APOE, a gene that can
increase an individual's risk of developing late-onset Alzheimer's.
An eye test being developed by Cognoptix is halfway through clinical trials. The
SAPPHIRE II is designed to detect a specific fluorescent signature of
ligand-marked beta amyloid in the lens of the eye.
Genetic tests are available to indicate increased risk for Alzheimer's, but
there are only a few rare genes that cause the disease directly. "It's something
that can be used as a risk factor but not a diagnostic test," says UM's Wright.
For family caregivers of Alzheimer's patients, tests that provide them with an
early diagnosis are a blessing in disguise.
Judy, a Coral Springs caregiver, has been caring for her 86-year-old mother
since she was diagnosed with Alzheimer's through clinical evaluation and an MRI.
The diagnosis helped the family put her financial and legal papers in order. It
did much more, too.
"When you get that early diagnosis, it helps you understand what is going on day
to day," Judy says. "When they do things that are off the wall, you're prepared
and you know it's part of the disease."
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