FAQ: Can Alzheimer's Be Diagnosed in Someone Who Doesn't Yet Have Any Symptoms?

2 answers | Last updated: Sep 14, 2017
A fellow caregiver asked...

Can Alzheimer's be diagnosed in someone who doesn't yet have any symptoms?

Expert Answers

Dr. Leslie Kernisan is the author of a popular blog and podcast at BetterHealthWhileAging.net. She is also a clinical instructor in the University of California, San Francisco, Division of Geriatrics.

Not yet in routine medical practice. Recently, Alzheimer's tests have been developed that can identify biomarkers known to be linked to the later development of dementia symptoms due to Alzheimer's disease. Because of this, in April 2011, a panel of experts recommended new criteria for diagnosing and defining Alzheimer's disease. Whereas the previous criteria (from 1984) required the presence of dementia symptoms in order to diagnose Alzheimer's disease, experts now believe that Alzheimer's disease involves a gradual progression through three main phases. These are: a preclinical phase with biomarkers but no symptoms; a middle phase of mild cognitive impairment during which some symptoms are detectable but the person can still function independently, and then a fully symptomatic phase of Alzheimer's dementia.

The new biomarker tests aren't yet standardized or widely available, however. Mostly they're now used to help identify and sort research subjects. Also, there's much that scientists don't yet understand about what these biomarkers mean over the longer term. For example, the presence of biomarkers doesn't reveal when actual disease symptoms might appear. It's also unclear whether all people who have biomarkers will even go on to develop symptoms. Adding another wrinkle: Dementia symptoms can be brought on by causes other than Alzheimer's, such as a brain tumor, medication side effects, or strokes. So a test may tell you that you're free of Alzheimer's biomarkers, but you could develop dementia of another stripe anyway.

A rare near-exception to foretelling Alzheimer's disease in someone who's having no symptoms is someone with a strong family history of early onset (before age 60, also called young-onset) Alzheimer's. Certain genes have been identified that are strongly associated with this form of the disease. For this unique subset of people, genetic testing can indicate one's likelihood of developing early onset Alzheimer's. However, only about 1 percent of all cases of Alzheimer's dementia are this familial early onset type.

Community Answers

Joseph.potocny answered...

Through a PET SCAN you can get an idea, brain shrinkage starts approx. 10 yrs before any onset of possible dementia. That has been released in recent studies regarding Alzheimer's. Although early PET Scans, CT Scans and MRIs with contrast could be possible precusors, I think some further study is needed, but like in my case things started some 10 years before the firm diag. of Alzheimer's & Frontal Temporal Dementia was made with a PET. But really medical profession has not come anywhere near where it should be with this disease.