Dementia is a decline in cognitive function. It may affect memory,
thinking, language, judgment, and behavior. Traditionally, a diagnosis of
dementia is based on noticeable signs of decline.
In April 2011, the National Institute on Aging (NIA) of the
National Institutes of Health (NIH) and the Alzheimer’s Association published
specific criteria for diagnosing dementia.
Dementia is diagnosed only when the following three criteria are
- The symptoms interfere with your ability to function at work or at
- The symptoms represent a decline from previous levels of
functioning and performing.
- The symptoms are not explained by delirium or a major psychiatric
In addition, your symptoms must
include at least two of the following:
- Impaired ability to acquire and remember new information. Symptoms
include: repeating questions or conversations; misplacing personal belongings;
forgetting events or appointments; getting lost on a familiar route.
- Impaired reasoning and handling of complex tasks and poor judgment.
Symptoms include: poor understanding of safety risks; inability to manage
finances; poor decision-making ability; inability to plan complex or sequential
- Impaired visuospatial ability. Symptoms include: inability to
recognize faces or common objects or to find objects in direct view despite
good acuity; inability to use simple tools or dress yourself.
- Impaired language functions. Symptoms include: difficulty thinking
of common words while speaking; hesitations; speech, spelling, and writing
- Changes in personality, behavior, or demeanor. Symptoms include:
uncharacteristic mood fluctuations such as agitation, impaired motivation,
apathy, social withdrawal, decreased interest in previous activities, loss of
empathy, compulsive or obsessive behaviors, and socially unacceptable behaviors.
doctor may be able to diagnose dementia based on a physical exam and health
history. The exam will include tests to check your mental function. This is
called a mental status examination. If this is not enough for a diagnosis, more
tests may be required.
detailed patient history will include:
- how and when symptoms developed
- your overall medical condition and history
- your family’s overall medical condition and history
- assessment of your emotional state and living environment
will also request information from your close friends and family members. This is
important because those closest to you may have observed changes in your
personality, behavior, memory, and cognitive skills.
physical exam includes checking your hearing, eyesight, heart, lungs,
temperature, blood pressure, and pulse. Your doctor may also order lab tests to
help eliminate or identify other health problems, particularly those associated
with reversible causes of mental status changes. Possible tests include:
- toxicology screen: Alcohol or medications can cause symptoms
- thyroid function tests: thyroid disease may cause altered
- blood chemistry: imbalance of certain electrolytes or evidence of
liver dysfunction may explain changes in brain function.
The most common test of this kind is the Mini-Mental State Exam
(MMSE). The MMSE includes 11 questions/tasks designed to evaluate your basic
mental status. Questions/tasks include:
- What is the date today?
- Where are we?
- Count to 100 by sevens.
- Write a sentence.
Pictures of your brain may help your doctor make an accurate
diagnosis. It is important to know the cause of your symptoms. This will help
determine if your condition can be treated or reversed.
Magnetic resonance imaging (MRI) and computed tomography (CT) scans can help
find or rule out brain tumors or blood clots that might be causing dementia.
A PET (positron emission tomography) scan allows
the doctor to see how your brain is functioning.
A functional MRI (fMRI) measures
the changes that take place in active parts of the brain.
A single photon-emission computed tomography (SPECT) shows
the distribution of blood in the brain, which generally increases with brain
Magnetoencephalography (MEG) shows
the electromagnetic fields produced by the brain's neuronal activity.