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Early Testing for Alzheimer’s Disease

Health Letter, February 2013

New tests have become available in recent years claiming the ability to discover and diagnose Alzheimer’s disease in its early stages, possibly even before the first mild symptoms of mental impairment begin to show. If you or a loved one are older and have experienced unusual memory loss or other signs of mental impairment, it may be tempting to try one of these tests to see if you might be experiencing the early stages of Alzheimer’s disease.

Yet these early tests leave unanswered many important questions about how the disease will progress, and no effective treatment has been identified to prevent or delay the decline in mental function caused by Alzheimer’s disease. This means that for many people, early testing will likely end up causing more problems than it solves and should thus be avoided in most cases.

Alzheimer’s disease and mild cognitive impairment

Alzheimer’s disease is one of the most common causes of dementia, particularly in people over the age of 65. The disease causes a slow, progressive decline in memory and mental (cognitive) function that eventually leads to dementia, a state of mental impairment serious enough to interfere with day-to-day life.

Alzheimer’s disease is definitively diagnosed and distinguished from other causes of dementia by the presence of a large number of abnormal formations in the brain known as amyloid plaques. The clearest way to diagnose a case of Alzheimer’s disease is after death, when the brain can be examined directly through an autopsy.

Currently there is no treatment that can prevent, cure or stop the decline in mental function in people with Alzheimer’s disease. Several drug therapies are currently marketed to treat later-stage Alzheimer’s disease symptoms, but Public Citizen’s WorstPills.org website has categorized each of these drugs as DO NOT USE, because none produce meaningful improvements in cognitive function and all have harmful side effects.

Alzheimer’s disease often progresses very slowly, with people in its early stages often experiencing some level of mild mental (cognitive) impairment but still living life as normal. Not all people with mild cognitive impairment will progress into Alzheimer’s-related dementia; in fact, they have a 12 percent chance of that happening each year. Some will never develop dementia or will develop it from causes other than Alzheimer’s disease.

It is difficult to predict whether a person with mild cognitive impairment will progress to Alzheimer’s-related dementia. Identifying Alzheimer’s patients early has historically been difficult, as doctors cannot usually examine a living person’s brain directly or take a biopsy (piece of tissue) to look for amyloid plaques. Furthermore, even if Alzheimer’s disease can be diagnosed at this stage, there is variation between individuals in terms of how a given number or type of abnormalities will affect symptoms of mental impairment.

Researchers have found that people with certain risk factors or conditions may be more likely to develop symptoms of dementia. For example, people with lower levels of education seem more likely to experience cognitive decline than people with higher education levels. Other risk factors include smoking, having hypertension or diabetes, or having a history of blood vessel problems (including stroke). There is limited evidence that people can actually reduce their risk of dementia by quitting smoking, living a heart-healthy lifestyle, and treating diabetes or hypertension.

Early testing for Alzheimer’s disease

Scientists have begun to experiment with tests to attempt to predict whether a person with mild (or even absent) symptoms may one day progress to Alzheimer’s-related dementia. These tests come in various forms. One widely publicized, expensive test involves using a positron emission tomography (PET) scan to search for the amyloid plaques in the brain that may begin to appear even before symptoms manifest. Researchers have found that healthy people with these plaques in their brains are more likely to develop Alzheimer’s-related dementia later in life. Other tests employ a series of different brain images combined with analysis of brain fluid to detect potential signs of early Alzheimer’s disease before symptoms begin to appear.

These tests help researchers learn more about the disease, and they may lead to accurate, early diagnosis in some cases. However, they also create stress, cost money and leave many questions unanswered for patients and their

Some people may gain satisfaction from knowing an Alzheimer’s disease diagnosis early, feeling it may allow them more time to prepare for the future by assessing care options and making important legal or financial arrangements. But learning a diagnosis also can be profoundly troubling and can create depression, anxiety and stress, both for the diagnosed individual and his or her family. Moreover, none of the current tests can help determine whether a person with early signs of Alzheimer’s disease will progress quickly to dementia or continue to live normally for years.

A diagnosis may help encourage a person to give up smoking, treat hypertension or diabetes, and live a healthier lifestyle. But these actions are generally recommended in the first place and may also help prevent other conditions, such as stroke, heart attack and organ damage.

Finally, these tests are costly, and an Alzheimer’s disease diagnosis may affect a person’s ability to obtain health insurance coverage. With all the pitfalls and costs of early testing, many — if not most — people are probably better off avoiding testing and focusing their energy on staying healthy.

Testing that may help

There are some tests for people with mild cognitive impairment that can be useful in identifying or excluding other conditions that may lead to reduced mental function. These conditions include nutritional deficiencies, sleep disorders, undiagnosed diabetes, autoimmune disorders, infections (such as Lyme disease), undetected cerebrovascular disease (such as stroke) or side effects from medications.

Testing also might be useful in helping to diagnose and manage symptoms. For example, PET scans are sometimes used to distinguish between Alzheimer’s disease and frontotemporal dementia, a disease that affects behavior and personality and is more likely to be found in younger people with dementia. There is no treatment that can cure or slow the progress of frontotemporal dementia, but the symptoms of this disease may be managed differently than the symptoms of Alzheimer’s disease.

Emerging research

Some doctors who engaged in Alzheimer’s research may encourage early testing and then offer enrollment in clinical trials to study new treatments for early Alzheimer’s disease. One current research strategy is to take the treatments that have failed to delay or reverse the decline in cognitive function for patients with later-stage Alzheimer’s disease and test them on patients with a less-advanced disease, in hopes that the timing of treatment will make a difference in effectiveness.

Patients should be cautious about enrolling in clinical trials for Alzheimer’s disease and recognize that any potential benefits from proposed treatments are still hypothetical at best. All of the drugs that have previously been tested for treatment of mild cognitive impairment have proven disappointing. While it is still possible that an effective treatment may be found to delay or prevent Alzheimer’s disease, patients should be wary of clinical tests or trials promising to diagnose and cure the disease, because it is still too early for researchers to know whether these products are actually effective.


It is normal for memory and other mental processes to decline with age, and mild cognitive impairment does not mean a person will develop dementia. If you notice that you or a loved one are beginning to have difficulties with memory loss or confusion, you should consult a doctor to see if the impairment may be due to a treatable condition.

Tell your doctor if you are taking sleeping pills or tranquilizers, as these drugs can cause side effects such as confusion and memory loss that may be reversed by stopping the medication. Other drugs, including certain antidepressants, also have been associated with impaired mental function. Your doctor should run tests for hypertension, diabetes, or an infection that affects the brain and nervous system, such as Lyme disease.

Think carefully before getting a PET scan or other test specifically designed to detect Alzheimer’s disease. Ask yourself what health steps you would take if you received an early Alzheimer’s diagnosis, and consider whether you could benefit from taking the same steps regardless of testing. One example would be scheduling an appointment with an attorney who specializes in elder law to discuss the legal issues that affect people as they age and begin to require greater assistance from family members and other caregivers.

Also, talk with your doctor about general steps you can take to stay mentally and physically healthy as you age, including quitting smoking, eating a heart-healthy diet, and controlling blood pressure and diabetes. A training program in problem-solving or other types of therapy could offer organizational strategies and other tools to cope with mild symptoms of confusion and memory loss. Counseling or medication may be necessary to help address depression, which is common in people with mild cognitive impairment and also may affect family members.

While it may be tempting to seek certainty from testing, remember that with or without an Alzheimer’s diagnosis, there always will be uncertainty about how symptoms of cognitive impairment will progress. Given the limited benefits of early testing, it is probably better to focus on the concrete, general steps one can take to stay healthy and plan for the future rather than putting effort and resources into obtaining an early diagnosis with no clear benefits.