Alzheimer's Disease Diagnosis & Tests
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Another problem in diagnosing Alzheimer's is that often there is more than one cause for the series of symptoms characteristic of dementia. Once the brain is compromised with something such as a small or major stroke, previous head injury, or oxygen interruption, the brain may be vulnerable to Alzheimer's, just as people with Alzheimer's may be more vulnerable to another brain condition that causes dementia.
In those cases, there is a mixed dementia that confounds a clear-cut diagnosis.
The only certain diagnosis for Alzheimer's disease cannot be done until after death, when evidence of plaques, tangles and shrinkage of the brain can be seen.
For living patients, doctors may test various bodily fluids, such as urine, blood and spinal fluid.
A doctor might also use a brain scan, such as MRI, PET or CT scan, to look for unusual formations in the brain.
An interview also can provide useful information about memory and other health issues. Some simple tests can also help find out more about the patient's attention span, counting abilities and short-term and long-term memory.
Most importantly, a doctor needs to rule out other potential causes for the patient's problems, such as other forms of dementia, cognitive impairments, minor strokes or other conditions that can produce symptoms similar to Alzheimer's.
Doctors use a variety of methods and tests to diagnose Alzheimer’s disease. They gather information through:
Part of diagnosing Alzheimer’s is ruling out other conditions that may cause memory loss. Once the evaluation is complete, a memory expert can evaluate the results and make a diagnosis. Although many patients view a memory evaluation as stressful, it does not have to be if you know what to expect. Familiarize yourself with the evaluation process to make the visit less daunting.
A definitive diagnosis can only be achieved by conducting a biopsy of the brain but doctors can with good certainty determine whether or not the patient is suffering from Alzheimer’s through the use of tests.
Alzheimer's disease is diagnosed upon the exclusion of other neurodegenerative disease processes that may cause cognitive impairment or memory changes. The best way to be certain that the diagnosis is Alzheimer’s is to have some simple but specific tests that can be ordered by a qualified clinician that practices in the area of dementia. Typically these tests include neuropsychological testing that can localize areas of the brain where the deficits are occurring thereby helping the clinician identify other disease processes, blood tests that can eliminate deficiencies that can contribute to cognitive changes and Neuroimaging studies such as Positron Emission Tomography (PET) which can reveal abnormal cellular activity in the brain. Currently there are no cures for Alzheimer’s disease but there are medications such as Donepezil (Aricept), Rivastigmine (Exelon) and Memantine (Namenda) that have had some success in slowing down the disease process.
Alzheimer's patients have characteristic changes in the brain, but there is no single, comprehensive test for diagnosing the disease. Doctors diagnose Alzheimer's by ruling out other conditions through a process of elimination. The only way to confirm a diagnosis of Alzheimer's disease is through autopsy.
When Alzheimer's disease is detected in its early stages, treatment can begin earlier and its effectiveness is increased as most medications currently available or in development can only slow the patient's descent into forgetfulness. Doctors at NewYork-Presbyterian are using a new brain imaging technique called quantitative diffusion tensor imagery to distinguish Alzheimer's from treatable disorders with similar symptoms such as normal pressure hydrocephaly. Doctors here also conduct genetic testing for the disease in people with a family history of Alzheimer's.
Alzheimer's disease can only be diagnosed with complete certainty after death using an autopsy. However, by questioning those affected and their family members, combined with using lab tests and brain scans, doctors are able to accurately diagnose Alzheimer's nine out of ten times. Using questions to determine someone's level of brain function can be very effective, as well as talking to family members about the symptoms being displayed.
Alzheimer's is difficult to diagnose because there are several causes of dementia, but blood tests can be used to narrow down the possible causes. Similarly, brain scans like magnetic resonance imaging (MRI) and computerized tomography (CT) can be used to look for visual clues.