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Alzheimer's Disease
Brain Changes, Symptoms
and Treatment
By Cari Nierenberg
Alzheimer's
disease is an incurable brain disorder that causes plaques to grow around nerve
cells, destroying them.
Alzheimer's
disease is a progressive brain disorder that causes problems with memory,
thinking and behavior in older adults.
The
disorder affects an estimated 5.7 million Americans, and is the fifth-leading
cause of death in people ages 65 and older, according to the Centers for
Disease Control and Prevention (CDC).
Alzheimer's
disease is often used as a synonym for dementia, which is a devastating loss of
memory and cognitive function in older people, said Dr. Brad Hyman, a
neurologist and director of the Massachusetts Disease Research Center at
Massachusetts General Hospital in Boston.
Dementia
is an umbrella term for impaired memory thinking skills, and Alzheimer's is a
specific form of dementia.
Alzheimer's
disease is responsible for 50-70% of all dementia cases, according to
Alzheimers.net.
The
first case of Alzheimer's was described in 1906 by Dr. Alois Alzheimer, a
German neurologist.
Alzheimer
identified two of the disease's key physical traits when he examined a woman's
brain tissue under a microscope after her death: He found abnormal protein
clumps (now known as amyloid plaques) and tangled bundles of nerve fibers (now
called neurofibrillary, or tau, tangles).
Brain
changes
An
explosion of research over the last five years has shed more light on what goes
wrong in the brain during Alzheimer's, Hyman told Live Science.
Four
things are seen in the brain tissue of a person who has died of the disease:
The two traits that Dr. Alzheimer noted, plus nerve cell loss and inflammation,
he said.
The
increased appearance of plaques, which are protein deposits that buildup in the
spaces between nerve cells, is widely believed to be what initiates the disease
in the brain, Hyman said.
Twisted
tangles of proteins called tau proteins can build up inside nerve cells, and
along with increased numbers of plaques, can block communication between nerve
cells.
The
continued loss of connections between nerve cells damages them to the point
that they can no longer function properly in the parts of the brain affecting
memory, and the nerve cells eventually die.
As
more nerve cells die, parts of the brain that control reasoning, language and
thinking skills are also affected, and brain tissue begins to shrink.
Researchers
also suspect that inflammation (excessive action of immune cells in the brain)
plays an important role in the progression of Alzheimer's and is more than a
side-effect of the disease, Hyman said.
Symptoms
The
brain changes associated with Alzheimer's may begin a decade or more before a
person begins experiencing symptoms, Hyman said.
The
most common early symptom of Alzheimer's is difficulty remembering newly
learned information, such as recent conversations, events or people's names,
according to the Alzheimer's Association.
But
not everyone has memory problems initially, and some people may first develop
changes in their behavior, language difficulties or vision problems.
According
to the Mayo Clinic, symptoms in people with mild-to-moderate forms of
Alzheimer's may include:
Repeating
statements and questions over and over.
Forgetting
conversations, appointments or events, and not remembering them later.
Routinely
misplacing possessions, and frequently putting them in illogical places.
Getting
lost in familiar places.
Forgetting
the names of loved ones and everyday objects.
Trouble
finding the right words to identify objects, expressing thoughts or
participating in conversations.
Having
difficulty concentrating and thinking, and managing finances.
Struggling
to do once-routine activities, such as cooking and playing a favorite game, and
eventually forgetting how to do basic tasks, such as getting dressed or
bathing.
Alzheimer's
also causes the following mood and behavior symptoms:
Apathy
Depression
Sleeplessness
Distrusting
others
Hallucinations
and delusions
Anger,
agitation and aggression
Loss
of inhibitions
Mood
swings
Social
withdrawal
Wandering
and pacing
People
with advanced-stage Alzheimer's experience a severe loss of brain function and
become completely dependent on others for their care.
According
to the National Institutes of Health, symptoms during this stage may include:
Weight
loss
Skin
infections
Difficulty
swallowing
Seizures
Groaning,
moaning or grunting
Increased
sleeping
Lack
of bladder and bowel control
In
Alzheimers disease plaques surround neurons and cause nerve cells in the brain
to die.
Causes
and risk factors
The
cause of Alzheimer's disease is unclear, but researchers suspect the disease is
triggered by a combination of genetic, lifestyle and environmental factors that
affect the brain over time.
Getting
older is the biggest risk factor for developing Alzheimer's. Early-onset
Alzheimer's affects people under age 60, and some forms may be inherited.
But
early-onset disease represents less than 10% of all people with the disorder,
according to the National Institute on Aging.
Late-onset
Alzheimer's is the more common form of the disease, and its first symptoms may
appear after age 65.
Besides
age, other risk factors for Alzheimer's disease, according to the Mayo Clinic,
include:
Family
History. People whose parents or siblings have Alzheimer's have a somewhat
higher risk of the disease.
Heredity.
Genetic mutations, such as inheriting the apolipoprotein-E gene, can contribute
to the development of Alzheimer's. (But genetic mutations account for less than
1% of people with Alzheimer's, according to the Mayo Clinic.)
Down
Syndrome. People with Down Syndrome are more at risk for Alzheimer's because
they have three copies of chromosome 21, which can lead to developing more
amyloid plaques in the brain.
Mild
cognitive impairment (MCI). People with MCI have more memory problems than normal
for their age, but symptoms don't interfere with their lives. MCI can increase
the risk of developing Alzheimer's.
Severe
head injuries. Head injuries have been linked with an increased risk of
Alzheimer's.
Low
education levels. People with less than a high-school education may be at
higher risk for Alzheimer's.
Diagnosis
While
there is no single test to diagnose Alzheimer's, doctors may examine a patient
for signs of stroke, tumors, thyroid disorders or vitamin deficiencies as these
factors also affect memory and cognition, Hyman said.
Doctors
will also perform a physical exam to assess the patient's balance, muscle
strength and coordination, and conduct neuropsychological tests of memory,
language and basic math skills.
Along
with reviewing the patient's medical history, the doctor may also survey family
or friends about the patient's behavior and personality changes.
In
the past few years, positron emission tomography (PET) scans of the brain,
which can detect whether plaques or tangles are present, have been used to
diagnose or monitor the disease, especially in research, Hyman said.
Another
exciting breakthrough is the use of cerebrospinal fluid from a spinal tap to
measure abnormal protein concentrations in the brain, which indicates the
presence of Alzheimer's, he said.
Dealing
with Alzheimer's disease is challenging, but there are medications to help
mitigate the symptoms.
Treatment
There
isn't a cure for Alzheimer's, but there are medications available that treat
some of the symptoms of the disease, Hyman said.
Cholinesterase
inhibitors are drugs that may help with symptoms such as agitation or
depression.
These
drugs include donepezil (Aricept), galantamine (Razadyne) and rivastigmine
(Exelon).
Another
medication known as memantine (Namenda) may be used to slow the progression of
symptoms in people with moderate to severe Alzheimer's.
Some
patients may be prescribed antidepressants to control behavioral symptoms.
Experts
agree that in addition to medication, lifestyle factors, such as staying
physically, mentally and socially active can all help the brain.
A
diet rich in fruits, vegetables and whole grains, with moderate amounts of
fish, poultry and dairy can also be beneficial.
Research
Alzheimer's
research has expanded significantly in the past decade, Hyman said.
Dozens
of clinical trials are aimed at finding treatments to slow the disease
progression or prevent it altogether, he said.
Previous
clinical trials focused on preventing the increase in plaques in the brain, but
those experimental therapies failed to produce dramatic results, Hyman said.
That
outcome suggests that the treatment was administered too late in the disease
progression.
Instead
of focusing on plaques, recent drug trials have focused on three other goals
for new therapies, Hyman explained.
One
is to explore whether there are ways to make the brain's remaining nerve cells
work better and more efficiently.
The
second is looking at ways to get rid of the tangles in the brain, and the third
is investigating whether decreasing inflammation can prevent harmful brain
changes, Hyman said.
Live Science is part of Future US Inc, an international media group
and leading digital publisher.
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