Can You Test for Dementia? The Cognitive and Memory Tests Used to Diagnose Dementia

It can take some time to diagnose someone with dementia. This is partly because there’s no simple or straightforward test for the condition. And the symptoms and progression can look different from person to person. Alzheimer’s disease is the most common type of dementia, representing over half of cases. But there are many different types of dementia, and each one has slightly different symptoms. Here, we’ll review how dementia is diagnosed, the typical tests used in diagnosis, and the potential pitfalls in the process. 

How is dementia diagnosed?

Below, we break down the typical process for diagnosing dementia.

Step 1: Rule out other conditions

There are many conditions that cause symptoms similar to dementia — like memory loss, confusion, behavior changes, or disorientation. 

The first step in diagnosing dementia is to ensure that there isn’t an alternative explanation for these symptoms. For that reason, healthcare providers work like detectives, often using blood tests and other studies to rule out other explanations like:

• Infection

• Dehydration

• Medication side effects

• Low blood counts 

• Kidney or liver failure

• Thyroid or hormone disorders

• Lung and heart disease

• Poor hearing

• Cancer

• Alcohol or drug use

• Mental health conditions, such as depression 

Step 2: Cognitive tests for dementia 

The next step in analyzing a person’s symptoms is cognitive testing. These tests are designed to assess brain functions that can be affected by dementia — like memory, thought processing, and reasoning. They’re typically performed by either a primary care provider or, sometimes, a neurology specialist.

There are many different tests that have been designed to evaluate cognition, and most of them take about 15 to 30 minutes to complete. These aren’t “pass/fail” tests, but instead a way to gauge how someone’s information processing and comprehension compares with others in their age range. 

Five of the most common tests include:

• Mini-Mental State Exam (MMSE): This test has been in use for more than 30 years and was originally designed to assess the cognitive status of hospitalized older adults. One of its weaknesses is that the MMSE doesn’t account for how mood can affect someone’s thinking, and it has some potential bias for English-speakers. 

• Montreal Cognitive Assessment (MoCA): This test has been around for about 20 years and was designed as a follow-up test for older adults who scored in the normal range on the MMSE but still have possible symptoms of dementia. MoCA also has a version for the visually impaired, called the “blind MoCA.”

• Saint Louis University Mental Status Exam (SLUMS): Compared with the NMSE, this test is able to tease out milder changes in orientation, thought processing, memory, and attention. SLUMS has a more difficult memory-test section and can be administered in many languages.

• Cognitive Linguistic Quick Test (CLQT): This test was designed for use in adults ages 18 to 89 years with known or suspected brain injuries. CLQT focuses on speech and language skills.

• Cognistat: This test was developed at Stanford University in 1979. Cognistat takes into account health conditions and medications that can affect test performance. 

But these aren’t the only tests that can help diagnose someone with dementia. 

Step 3: Additional tests for dementia

If someone’s cognitive evaluation suggests they may have dementia, a healthcare provider may recommend follow-up tests. These are most commonly brain-imaging studies. 

Imaging studies can diagnose things like strokes, tumors, bleeding, brain-cell damage, blood clots, and protein buildup. So they can help rule out other causes. But they also might show some changes in the brain that are seen in dementia.

Common brain-imaging tests include:

• CT scan (computed tomography) uses two-dimensional X-ray technology to show bleeding, swelling, or other brain injuries.

• MRI (magnetic resonance imaging) uses magnets and radio waves to create a highly detailed picture of the brain. It can pick up on small abnormalities that a CT scan might miss.

• Angiography looks specifically at the blood vessels in the brain to check for blockages or clots.

Another test that can help diagnose dementia is a lumbar puncture. This is a procedure that’s used to collect a small sample of the fluid that surrounds the brain and spinal cord. The sample is collected using a small needle, inserted into the lower back. The fluid can then be tested for specific proteins that are increased in someone with dementia.

Cognitive-screening tests for dementia you can do at home

Now that you understand how complicated it is to diagnose dementia, you can imagine that there isn’t a good “do-it-yourself” option here. But there are some brief screening tests available online that provide a very general sense of whether a person’s mental capabilities are roughly in the typical range. 

Keeping the limitations of at-home testing in mind, there are online cognitive tests available if you’re concerned about yourself or a loved one. It’s important to discuss any concerns (or test results) with a healthcare provider so they can help.

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Written by:

Valerie Anne Jones, MD

Val Jones, MD, is a physician who is certified by the American Board of Physical Medicine and Rehabilitation (ABPMR).

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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