Study: 1 in 5 Alzheimer’s Cases Could be Misdiagnosed

Alzheimer's disease
Science & Medicine

Two new studies have shown that Alzheimer’s disease is frequently misdiagnosed. The rate of misdiagnosis may even be as high as 1 in 5 people being diagnosed incorrectly, which can lead to significant emotional consequences.

The issue also extends to those who are not diagnosed as having Alzheimer’s, but actually do, which also leads to incorrect treatment and further stress. Findings from both of these studies were presented at Alzheimer’s Association International Conference, held from July 22 to 28 in Toronto, Canada.

In the first study, a team from the Mayo Clinic in Jacksonville, Florida, found that men are often highly misdiagnosed with Alzheimer’s, and at a much higher rate than their female counterparts. The conclusion was arrived through a study of 1,606 brains of people ages 37 to 102 in the State of Florida brain bank. The misdiagnoses of men can be for a variety of reasons, but Melissa Murray, PhD, and her team think it is because many men who develop Alzheimer’s do so at a younger at than women.

While most women don’t begin to show symptoms until their 70’s, 80’s, or even 90’s, many men begin to display them in their 60’s. Often for men, the form of Alzheimer’s is much more aggressive than in women and their symptoms may not be that of classic memory loss. Instead, many men with Alzheimer’s may experience a behavioral change, problems with words or motor skill issues which may lead to a misdiagnoses.

The second study confirmed that misdiagnoses happen often. A team from Keenan Research Centre for Biomedical Science at St. Michael’s Hospital in Toronto examined the brains of 1,073 people who were registered with the National Alzheimer’s Coordinating Center database.

They found through brain autopsies that 78.4 percent of the patients were correctly diagnosed with Alzheimer’s, whereas 10.8 percent of people previously diagnosed actually did not have Alzheimer’s. A further 10.8 percent of people who were not diagnosed with Alzheimer’s actually had it according to the brain autopsies.

Here is what the research says:

  • “841 (78.4%) had a clinical diagnosis and autopsy confirmation of Alzheimer’s using the NIAReagan criteria.

  • 116 (10.8%) were diagnosed with Alzheimer’s in the clinic but, on autopsy, did not have the brain changes necessary for an Alzheimer’s diagnosis (“false positives”). In other words, some disease or condition other than Alzheimer’s was causing their dementia.
  • 116 (10.8%) had Alzheimer’s changes in their brains, but were not clinically diagnosed with Alzheimer’s (“false negatives”).”

Senior researcher and adjunct scientist at St. Michael’s stated:

“Even with all the latest diagnostic methods, the discrepancy between the clinical diagnosis of Alzheimer’s disease and the pathological diagnosis is about 20 percent.”



CBS News