Alzheimer's Disease Diagnosis
In the past, Alzheimer’s disease (AD) was only confirmed after a
person had died and an autopsy was performed on the brain. Today, physicians
are able to make an accurate diagnosis in a living person.
Still, the diagnosis of AD is not an exact science. There are
various conditions that show similar symptoms to AD. And while genetics play a
role, approximately 75 percent of individuals with AD have no known family history of the
condition. It’s essential that you consult with a doctor experienced in diagnosing
An experienced AD doctor will take the following steps.
A detailed patient history will be conducted, including:
- description of
how and when symptoms developed
- description of
the person’s overall medical condition and history
- description of
the family’s overall medical condition and history
- assessment of
the person’s emotional state and living environment
Also, the doctor may speak with the patient’s friends and family.
They can offer insight into his or her personality, behavior, memory, and
Physical Examination and Lab Tests
A comprehensive physical exam will be conducted, including:
- an evaluation of
the patient’s hearing, sight, heart, lungs, temperature, blood pressure,
and pulse readings
- lab tests (
blood, urine, and possibly spinal fluid examination) may be performed to
help eliminate or identify additional health problems, such as diabetes,
thyroid, or liver problems
The most common neuropsychological test is the Mini-Mental State Exam (MMSE). The
MMSE includes a selection of questions and tasks designed to evaluate a
patient’s basic cognitive (mental) status. Examples include questions such as:
do they know today’s date and where they are? can they repeat a list of words
or a phrases? can they count backwards from 100 by sevens? This test is not
perfect. For example, the results can be affected by a person’s level of
education. Yet it is a good starting point for assessing AD.
- MRI (magnetic
resonance imaging) and CT (computed tomography) scans: These diagnostic tools can
rule out other reasons for AD symptoms, such as brain tumors or blood
- PET (positron
emission tomography) scan: This allows a doctor to see areas and
intensity of metabolic activity in
the brain, using radioactive glucose.
Diagnosing early-onset AD (when symptoms appear in a person well
before the age of 60) will likely include genetic testing.
The Latest in AD Diagnostics Criteria
Diagnosing dementias and AD used to be straightforward. Family or
friends would notice problems with a person’s ability to think, learn, and
But our knowledge about dementias and AD has increased over the
years. It is now believed AD creates changes in the brain years, and even
decades, before symptoms
show up. In response, the National Institute on Aging (NIA), the National Institutes
of Health (NIH), and the Alzheimer’s Association have published the
following three phases to better reflect AD progression over time.
Preclinical Alzheimer’s Disease
This involves changes that may indicate the earliest signs of AD.
Examples include measurable changes in biomarkers, such as brain imaging and
spinal fluid chemistry. Currently, there are no clinical diagnostic criteria
for this phase. But an outline has been created to help define this AD stage.
Mild Cognitive Impairment (MCI) Due To Alzheimer’s Disease
This denotes mild changes in memory and thinking abilities that
can be measured. These changes are noticeable, but they are not severe enough
to affect a person’s ability to function independently and perform everyday
Dementia Due To Alzheimer’s Disease
This denotes cognitive (e.g. memory and thinking) and behavioral
symptoms that impair a person’s ability to function in daily life.