Memory Loss Testing

Tests can measure and categorize memory loss, and can help make diagnosis of any disease underlying that memory loss more accurate.

Tests your doctor may conduct or order include:

• “Mental status” tests (also called cognitive tests or neuropsychological tests) to measure or categorize any memory loss.  To begin with, your doctor may use a brief test called the “Mini-Cog.”  During this test, your doctor will say three words, then ask you to remember them in a few minutes.  In addition, he will ask you to draw a clock face. 

Another brief test called the Mini-Mental Status Exam, or MMSE, is often administered in the doctor’s office.  During this test, the doctor will ask you some questions and also have you complete some exercises with pencil and paper. 

Results of these brief mental status tests do not necessarily show how well you are functioning in daily life. In addition, the MMSE may not be sensitive enough to detect early memory loss.

Your doctor may also ask you to take an approximately 30 minute test called ADAS-Cog.  More in-depth neuropsychological testing may include combinations of tests to assess various types of memory and skills (including language, visuo-spatial, concentration, and problem solving). 

• Blood or urine tests to check for certain conditions associated with memory loss (for example thyroid problems or vitamin deficiencies)

• Brain imaging, typically an MRI (Magnetic Resonance Imaging) or a CT (Computed Tomography) scan.  MRIs and CT scans (also called CAT scans) are structural imaging tests.  These scans are used to look at the volume and shape of the brain, and also to check for signs of stroke, tumors or head injuries that might cause memory problems. 

Functional brain imaging is used to see how the brain uses sugars and oxygen.  Functional MRIs (fMRIs), PET scans and SPECT (single-photon emission computed tomography) are examples of functional imaging.  Some types of functional brain imaging are available only in research clinics.

• Spinal fluid testing can be used to measure levels of proteins associated with Alzheimer’s disease.  Because it is invasive, your doctor may not order this test.

• Genetic testing  - one genetic variation, APOE4, is associated with an increased risk of developing dementia after age 65, and testing for this variation may be used to help confirm a diagnosis.  Some people who have the APOE4 genetic variation never develop Alzheimer’s, though, and some people who do not have the variation do develop the disease.  The inconclusive nature of the APOE test, along with concerns about confidentiality, legal and psychological issues, makes many doctors reluctant to order this test.  Researchers continue to search for other variations, or combinations of variations, that may increase the risk of late-life dementia. 

Three genetic variations (called APP, PS1, PS2) cause rare young onset (under age 65) Alzheimer’s that runs in families.  Doctors may wish to order these tests for patients with inherited young onset Alzheimer’s, but the tests are not always commercially available.

Researchers are working to identify “biomarkers” for Alzheimer’s and related diseases.  Biomarkers are characteristics that indicate the presence of a disease.  Potential candidates are substances in blood, urine, skin tissue, eye tissue, and loss of sense of smell.

Learn More:

Tangled Neuron Posts:

A Quick and Easy Biomarker for Alzheimer’s?
Detecting Alzheimer’s and Other Disorders Before Symptoms Appear:  the FDDNP-PET Scan
Alzheimer's Risk Factors, Genetics, Family History and Prevention
Dr. Rudolph Tanzi's Talk on Alzheimer's Genetics and Treatments
SORL1: New Alzheimer's Gene
The APOE Gene, Alzheimer's and Dementia
The MTHFR gene and Alzheimer's
Can loss of sense of smell predict Alzheimer's?
The Eye Exam Every Dementia Patient Should Have?
The MRI Every dementia Patient Should Get?

Other Resources:

Alzheimer Research Forum’s Neuropsychological Testing Information
Alzheimer’s Association Steps to Diagnosis Page (including discussion of MMSE scores)
Summary of a study about PET scans for evaluation of dementia
Summary of a study of PET scans using PIB for imaging amyloid deposits in the brain
Fisher Center for Alzheimer’s Genetic (Inherited) Factors Page
The American Geriatrics Society Position Statement on Genetic Testing for Late-Onset Alzheimer’s Disease
New York Times article about testing for the APOE4 genetic variation

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