Laboratory tests

You may have laboratory tests to rule out other disorders that cause some symptoms similar to those of Alzheimer's dementia, such as a thyroid disorder or vitamin B-12 deficiency.

Brain-imaging tests

Alzheimer's dementia results from the progressive loss (degeneration) of brain cells. This degeneration may show up in a variety of ways in brain scans.

However, these scans alone aren't enough to make a diagnosis. Scans aren't used to diagnose the condition because there is overlap in what doctors consider normal age-related change in the brain and abnormal change.

However, brain imaging can help:

  • Rule out other causes, such as hemorrhages, brain tumors or strokes
  • Distinguish between different types of degenerative brain disease
  • Establish a baseline about the degree of degeneration

The brain-imaging technologies most often used are:

  • Magnetic resonance imaging (MRI). An MRI uses powerful radio waves and magnets to create a detailed view of your brain.
  • Computerized tomography (CT). A CT scan uses X-rays to obtain cross-sectional images of your brain.
  • Positron emission tomography (PET). A PET scan uses a radioactive substance known as a tracer to detect substances in the body. There are different types of PET scans. The most commonly used PET scan is a fluorodeoxyglucose (FDG) PET scan, which can identify brain regions with decreased glucose metabolism. The pattern of metabolism change can distinguish between different types of degenerative brain disease.

    PET scans have recently been developed that detect clusters of amyloid proteins (plaques), which are associated with Alzheimer's dementia, but this type of PET scan is typically used in the research setting.

Future of diagnosis

Researchers are working on new diagnostic tools that may enable doctors to diagnose Alzheimer's dementia earlier in the course of the disease, when symptoms are very mild or before symptoms even appear. One such tool is a PET scan that can detect tau, the other hallmark abnormal protein in Alzheimer's dementia.

Scientists are investigating a number of disease markers and diagnostic tests, such as genes, disease-related proteins and imaging procedures, which may accurately and reliably indicate whether you have Alzheimer's dementia and how much the disease has progressed. However, more research on these tests is necessary.

Benefit of an early diagnosis

Reluctance to go to the doctor when you or a family member has memory problems is understandable. Some people hide their symptoms, or family members cover for them. That's easy to understand, because Alzheimer's dementia is associated with loss, such as loss of independence, loss of a driving privileges and loss of self. Many people may wonder if there's any point in a diagnosis if there's no cure for the disease.

It's true that if you have Alzheimer's dementia or a related disease, doctors can't offer a cure. But getting an early diagnosis can be beneficial. Knowing what you can do is just as important as knowing what you can't do. If a person has another treatable condition that's causing the cognitive impairment or somehow complicating the impairment, then doctors can start treatments.

For those with Alzheimer's dementia, doctors can offer drug and nondrug interventions that may ease the burden of the disease. Doctors often prescribe drugs that may slow the decline in memory and other cognitive skills. You may also be able to participate in clinical trials.

Also, doctors can teach you and your caregivers about strategies to enhance your living environment, establish routines, plan activities and manage changes in skills to minimize the effect of the disease on your everyday life.

Importantly, an early diagnosis also helps you, your family and caregivers plan for the future. You'll have the chance to make informed decisions on a number of issues, such as:

  • Appropriate community services and resources
  • Options for residential and at-home care
  • Plans for handling financial issues
  • Expectations for future care and medical decisions

When a doctor tells you and your family members about an Alzheimer's diagnosis, he or she will help you understand Alzheimer's dementia, answer questions and explain what to expect. Doctors will explain what capacities are preserved and how to limit future disabilities, and look to keep you as healthy and safe as possible with the least disruption in your daily activities.

Oct. 13, 2016