How Do Doctors Test for Dementia?

How Do Doctors Test for Dementia?

How Do Doctors Test for Dementia?

We live in a great age of medical breakthroughs. We have rapid tests for a lot of conditions—everything from being pregnant to having COVID. Various tests can be performed right in a doctor’s office with a high degree of accuracy.

And then there’s diagnosing dementia, where the wheels of progress screech to a…crawl.

It is getting better, this “identifying the enemy.” I grew up during a time when the diagnosis was little more than an educated guess by doctors. Today, I recognize the symptoms experienced by my great-grandfather as clearly being Alzheimer’s with a high degree of sundowning, but in 1981 as his birthday ushered him into triple digits, doctors were chalking his behaviors up to “old age.”

So the great news is that today, doctors can diagnose Alzheimer’s with 90 percent accuracy while the patient is still living[i]—quite an improvement over the previous method of having to do a brain autopsy to know for sure.

As I’ve been working to convert the chapters of my course Everything I Wish I Had Known: Caring for a Loved One With Alzheimer’s or Other Dementia into seminar material I plan to teach, I’ve been reminded about how doctors discern whether a patient has dementia or not. There has definitely been progress, but there’s still a lot of work to be done.

If dementia is suspected, one of the first things a doctor will do is order bloodwork. Since there are a variety of conditions with symptoms that can mimic dementia—but aren’t really dementia at all—blood tests are used to clear up the mystery. There’s a decent-sized list of things that can cause dementia-like symptoms, including:

  • Thyroid issues
  • Vitamin B12 deficiency
  • Depression
  • Untreated infections

And this list is by no means exhaustive, but you get the idea.

If the blood tests don’t reveal anything specific, doctors will endeavor to figure out what’s really going on through other means. A typical starting point is to verbally screen the patient for cognitive decline using a series of questions. Doctors work between the “Mini-Mental State Examination” (MMSE) and the “Montreal Cognitive Assessment” (MoCA). The tests are similar in that they both ask questions about date, time and location, but the MoCA tests for executive function (which includes working memory, flexible thinking and self-control), so it’s considered a better indicator of mild forms of cognitive disease.

These cognitive tests are very telling, but before pronouncing a diagnosis of dementia, they need to be considered along with the results of other tests such as an MRI, a CT scan or a PET scan. The diagnosis of various dementia types can be made by putting together the evidence of the verbal tests along with the scan results—as well as the input of family caregivers’ observations.

It’s been almost 40 years since my great-grandfather passed away at the ripe old age of 103. Progress that’s slow is still progress, and there has been progress made toward more accurate diagnoses of the various dementia types. And while that’s good, I’m still holding out for progress to be made toward a complete end of all dementia. That will definitely be worth celebrating.

[i] Alissa Sauer, “How Alzheimer’s is Diagnosed,”, A Place for Mom, Updated August 13, 2019:


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