How Is Alzheimer's Disease Diagnosed?
Doctors use several methods and tools to help determine whether a person who is having memory problems has “possible Alzheimer’s dementia” (dementia may be due to another cause), “probable Alzheimer’s dementia” (no other cause for dementia can be found), or some other problem.
To diagnose Alzheimer’s, doctors may:
- Ask the person and a family member or friend questions about overall health, use of prescription and over-the-counter medicines, diet, past medical problems, ability to carry out daily activities, and changes in behavior and personality
- Conduct tests of memory, problem solving, attention, counting, and language
- Carry out standard medical tests, such as blood and urine tests, to identify other possible causes of the problem
- Perform brain scans, such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET), to rule out other possible causes for symptoms
These tests may be repeated to give doctors information about how the person’s memory and other cognitive functions are changing over time. They can also help diagnose other causes of memory problems, such as stroke, tumor, Parkinson’s disease, sleep disturbances, side effects of medication, an infection, mild cognitive impairment, or a non-Alzheimer’s dementia, including vascular dementia. Some of these conditions may be treatable and possibly reversible.
People with memory problems should return to the doctor every 6 to 12 months.
It’s important to note that Alzheimer’s disease can be definitively diagnosed only after death, by linking clinical measures with an examination of brain tissue in an autopsy. Occasionally, biomarkers—measures of what is happening inside the living body—are used to diagnose Alzheimer's.
What Happens if a Doctor Thinks It's Alzheimer's Disease?
If a primary care doctor suspects mild cognitive impairment or possible Alzheimer’s, he or she may refer the patient to a specialist who can provide a detailed diagnosis or further assessment. Specialists include:
- Geriatricians, who manage health care in older adults and know how the body changes as it ages and whether symptoms indicate a serious problem
- Geriatric psychiatrists, who specialize in the mental and emotional problems of older adults and can assess memory and thinking problems
- Neurologists, who specialize in abnormalities of the brain and central nervous system and can conduct and review brain scans
- Neuropsychologists, who can conduct tests of memory and thinking
Memory clinics and centers, including Alzheimer’s Disease Research Centers, offer teams of specialists who work together to diagnose the problem. Tests often are done at the clinic or center, which can speed up diagnosis.
What Are the Benefits of an Early Alzheimer's Diagnosis?
Early, accurate diagnosis is beneficial for several reasons. Beginning treatment early in the disease process may help preserve daily functioning for some time, even though the underlying Alzheimer’s process cannot be stopped or reversed.
Having an early diagnosis helps people with Alzheimer’s and their families:
- Plan for the future
- Take care of financial and legal matters
- Address potential safety issues
- Learn about living arrangements
- Develop support networks
In addition, an early diagnosis gives people greater opportunities to participate in clinical trials that are testing possible new treatments for Alzheimer’s disease or in other research studies.
Learn more about Alzheimer's disease from MedlinePlus.
For More Information About Alzheimer's Diagnosis
This content is provided by the National Institute on Aging (NIA), part of the National Institutes of Health. NIA scientists and other experts review this content to ensure that it is accurate, authoritative, and up to date.
Content reviewed: May 22, 2017