There are a number of test procedures carried out to diagnose a person with Alzheimer's disease, including clinical and cognitive evaluations, blood tests and brain imaging. While some are done to aid the initial suspicion of Alzheimer's disease, others are used for confirmation and to rule out other possible causes of symptoms.
Clinical Evaluation
The first assessment procedure involves questioning about symptoms. It is important here to have a person close to the patient available to also answer questions, as people with Alzheimer's disease can lose the ability to judge situations properly and to recall recent memories. Symptoms of Alzheimer's disease include disruptive memory loss; confusion with time and place; mood and behavior changes; difficulties with problem solving, completing tasks, understanding visual images and finding words; misplacing things; and social withdrawal. While people with early Alzheimer's may not have all of these symptoms, a diagnosis is suspected when they have three or more, according to the Alzheimer's Association.
Another part of the evaluation is to assess a patient's medical history and any medications a person is taking to rule out whether symptoms are due to a different disorder or medication side effects. A physical evaluation is also carried out to assess whether the patient may have a medical problem whose symptoms could be similar to those of Alzheimer's disease, such as a stroke or a head injury.
Cognitive Evaluation
An important part of the Alzheimer's testing procedure is assessing a person's cognitive abilities. Tests generally involve two parts: the first includes performance of a task such as folding a piece of paper and putting it on the ground, doing simple arithmetic or copying a shape. These assess symptoms such as confusion, problem solving and difficulty understanding visual images. The second part involves answering questions to establish if a person knows where he is in time and place. These can help assess if long- or short-term memory, or both, are affected, as people with Alzheimer's disease mainly have only short-term memory problems.
Tests for cognitive evaluation include the Mini-Mental State Examination, or MMSE, the "clock drawing test," the General Practitioner Assessment of Cognition, or GPCOG, the 7-Minute Screen and the Behavioral Neurology Assessment Short Form, or BNAS. Evaluation may involve more than one of these tests because while several look at similar areas--for instance the MMSE, GPCOG and BNAS all test for recalled memory and orientation--others examine different skills, like the clock drawing test that evaluates executive functioning, and only the GPCOG includes assessment of activities of daily living.
Other Evaluations
For a person to be properly diagnosed with Alzheimer's disease, she will need to undergo other test procedures, including blood draws and neuroimaging. Most commonly blood tests are used to rule out other problems that can cause Alzheimer's-like symptoms, such as alterations in glucose levels, electrolyte imbalances and vitamin B12 deficiency.
Imaging of the brain is carried out using procedures like computed tomography and magnetic resonance imaging, which involve the patient lying with his head inside the machine that produces these pictures. Some of these tests involve injection of a harmless dye that can help highlight specific aspects of the brain. These tests not only look for characteristic brain insults of Alzheimer's disease, such as shrinking of some tissue areas and enlargement of some fluid-filled areas, but they are also used to rule out other problems like a ruptured blood vessel or a tumor.
References
- "Alzheimer's Association;" 10 Signs of Alzheimer's
- "Canadian Medical Association Journal;" Diagnosis and Treatment of Dementia: 2. Diagnosis; Howard Feldman et al; March 2008
- "American Family Physician"; Early Diagnosis of Dementia; Karen Santacruz and Daniel Swagerty; February 2001
- Alzheimer's Association: Diagnosing Alzheimer's
