How To Diagnose Alzheimer’s Disease

Although there is not a single, definitive diagnostic test for Alzheimer's, experts have developed a multimodal approach for diagnosis in their diagnoistic guidelines. The core components of these guidelines include a clinical history of cognitive decline and neurocognitive testing results that show clear deficits.

Woman reviewing brain imaging with her doctor

Brain imaging is one tool your doctor can use to help arrive at a diagnosis.

Photo: © Chinnapong | iStock / Getty Images Plus

For most individuals, an Alzheimer’s diagnosis will begin with a visit to your primary care provider. Your doctor will review your personal and family medical history, ask you about any symptoms you’ve experienced, review your medications, and give you a physical exam. He or she will likely administer a simple cognitive screening test, such as the Montreal Cognitive Assessment (MoCA) or Mini-Mental State Exam (MMSE), to look for formal evidence of cognitive decline.

You also may be referred to a neuropsychologist for tests that measure aspects of brain function such as memory, attention, executive functions (such as problem-solving abilities, calculation, and abstraction), language skills, and visuo-spatial abilities. Research reinforces the importance of cognitive testing in early disease detection.

Cognitive Function Tests

General diagnostic and cognitive function tests include:

General Practitioner Assessment of Cognition (GPCOG). This brief screening assessment incorporates both short-term recall and time/date orientation with a caregiver question list to highlight recent symptoms and changes in daily functioning. This test is typically used for the cognitive assessment that is now a part of the Medicare Annual Wellness visit.

Mini-Mental State Examination (MMSE). Your doctor will ask you a series of questions, such as the names of common objects, the date, the location of your doctor’s office, or to follow an instruction). The maximum score on the MMSE is 30 points. A score of 20 to 24 suggests mild dementia, 13 to 20 suggests moderate dementia, and less than 12 indicates severe dementia.

Montreal Cognitive Assessment Test (MoCA). The MoCA is a more sensitive test than the MMSE, especially for mild cognitive impairment (MCI) and mild or early-onset AD. Like the MMSE, it takes about 10 minutes to complete, and the maximum score is 30 points. MoCA is 100 percent sensitive at detecting mild AD, and 90 percent sensitive at detecting MCI.

Mini-Cog. This test asks you to remember the names of three common objects and then repeat them a few minutes later. You’ll also be asked to draw a clock showing a time your doctor specifies.

Computerized Tests. These tests offer an advantage over paper tests in that they are standardized, so they can be administered in exactly the same way each time they’re given. The U.S. Food & Drug Administration (FDA) has approved several computerized tests. These include CANTAB Mobile, a 10-minute memory test done using a touchscreen on a computer tablet or iPad; Cognivue, a computer-based test that creates a single brain health score; ANAM, a computer-based cognitive assessment program originally developed by the military for traumatic brain injury evaluation; and COGNIGRAM, another digital assessment tool that can be used on a one-time basis or for ongoing assessment.

Care Giver or Informant Testing. The 2011 diagnostic guidelines emphasized the importance of involving an “informant,” an individual who knows the patient well and who spends enough time with them to be able to comment on changes in cognition and behavior.

Behavioral Checklist. Current diagnostic tests focus on loss of memory and other cognitive abilities. Researchers are working on a different kind of checklist that might help identify people at risk for AD based on behavioral symptoms. The Mild Behavioral Impairment Checklist (MBI-C) looks at a collection of behaviors that can precede MCI— apathy/drive/motivation; mood/affect/anxiety; impulse control/agitation/reward; social appropriateness; and thoughts/perception. For a diagnosis of MCI, the symptoms must have continued for at least six months. The creators of the checklist say that once it has been refined, the scale may serve as a guide to researchers, as well as to family members of older adults at risk for dementia.

Blood and Urine Tests. These tests can rule out conditions that cause memory loss, such as thyroid problems, kidney or liver dysfunction, and infections. Initial screening blood tests typically include thyroid stimulating hormone, vitamin B12, homocysteine, complete blood count, complete metabolic panel, erythryocyte sedimentation rate, and C-reactive protein.

Neurological Tests. Your doctor will check your coordination, strength and muscle tone, balance, eye movement, speech, and reflexes to look for other brain disorders, such as a stroke or ­Parkinson’s disease.

Brain Imaging. Your doctor may recommend brain imaging to help arrive at a diagnosis.

  • Computed tomography (CT) provides a three-dimensional view of your brain to help your doctor spot a stroke or bleeding in the brain.
  • Magnetic resonance imaging (MRI) identifies abnormalities in brain structure with sharper resolution than CT scans and can help doctors assess the structure of your brain.
  • PET scans are used to examine brain metabolism and look for areas with reduced metabolism that may be suggestive of lower brain activity. In addition, new PET tests can identify brain amyloid or tau, although these tests  may not be covered by insurance.

To learn more about conditions that affect your memory, purchase Combating Memory Loss at www.UniversityHealthNews.com.

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Lynne Christensen

Lynne Christensen is executive editor of the Cleveland Clinic Arthritis Advisor newsletter. After completing her undergraduate degree from New York University, Christensen earned a master’s degree in biological studies from … Read More

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