Exams and Tests
Doctors diagnose the cause of dementia by asking questions about the person's medical history and doing a physical exam, a mental status exam, and lab and imaging tests.
Tests can help the doctor learn whether dementia is caused by a treatable condition. Even for those dementias that cannot be reversed, knowing the type of dementia a person has can help the doctor prescribe medicines or other treatments that may improve mood and behavior and help the family.
During a Reference medical history and physical exam, the doctor will ask the affected person and a close relative or partner about recent illnesses or other life events that could cause memory loss or other symptoms such as behavioral problems. The doctor may ask the person to bring in all medicines he or she takes. This can help the doctor find out if the problem might be caused by the person being overmedicated or having a drug interaction.
Although a person may have more than one illness causing dementia, symptoms sometimes can distinguish one form from another. For example, early in the course of Reference frontotemporal dementia Opens New Window, people may display a lack of social awareness and develop obsessions with eating, neither of which occurs early in other dementias.
Mental status exam
A doctor or other health professional will conduct a Reference mental status exam. This test usually involves such activities as having the person tell what day and year it is, repeat a series of words, draw a clock face, and count back from 100 by 7s.
Other tests have been developed to diagnose dementia. Doctors can use one such test, Addenbrooke's Cognitive Examination, to distinguish Alzheimer's disease from frontotemporal dementia. Orientation, attention, and memory are worse in Alzheimer's, while language skills and ability to name objects are worse in frontotemporal dementia.
Many medical conditions can cause mental impairment. During a physical exam, the doctor will look for signs of other medical conditions and have lab tests done to find any treatable condition. Routine tests include:
- Reference Thyroid hormone tests to check for an underactive thyroid.
- Reference Vitamin B12 blood test to look for a vitamin deficiency.
- Reference Complete blood count, or CBC, to look for infections.
- Reference ALT or Reference AST, blood tests that check liver function.
- Reference Chemistry screen to check the level of electrolytes in the blood and to check kidney function.
- Reference Glucose test to check the level of sugar in the blood.
Other lab tests that may be done include:
- HIV testing to look for Reference AIDS Opens New Window.
- Reference Erythrocyte sedimentation rate, a blood test that looks for signs of inflammation in the body.
- Reference Toxicology screen, which examines blood, urine, or hair to look for drugs that could be causing problems.
- Reference Antinuclear antibodies, a blood test used to diagnose Reference autoimmune diseases Opens New Window.
- Testing for heavy metals in the blood, such as a Reference lead test.
- A lumbar puncture to test for certain proteins in the Reference spinal fluid Opens New Window. This test may also be done to rule out other causes of symptoms.
Brain imaging tests such as Reference CT scans and Reference MRI may also be done to make sure another problem isn't causing the symptoms. These tests may rule out brain tumors, strokes, Reference normal-pressure hydrocephalus Opens New Window, or other conditions that could cause dementia symptoms.
MRI can show shrinkage in Reference parts of the brain Opens New Window Reference Opens New Window that occurs in some types of dementia. MRI and CT scan also can show evidence of strokes from Reference vascular dementia Opens New Window.
Two other forms of imaging—single photon emission CT (SPECT) and Reference PET scan Opens New Window—are not used routinely to diagnose dementia. But they may be useful if the symptoms are confusing or odd. These tests can help identify several forms of dementia, including vascular dementia and frontotemporal dementia.
In some cases, electrical activity in the brain may be measured using an Reference electroencephalogram (EEG). Doctors seldom use this test to diagnose dementia, but they may use it to distinguish dementia from Reference delirium Opens New Window and to look for unusual brain activity found in Creutzfeldt-Jakob disease, a rare cause of dementia.
In rare cases, a brain Reference biopsy Opens New Window may be done if a treatable cause of dementia is suspected.
After death, an autopsy may be done to find out for sure what caused dementia. This information may be helpful to family members concerned about genetic causes.
|By:||Reference Healthwise Staff||Last Revised: Reference August 11, 2011|
|Medical Review:||Reference Anne C. Poinier, MD - Internal Medicine
Reference Peter J. Whitehouse, MD - Neurology