Thursday, October 19, 2017

Scary Alzheimer's

Halloween is approaching and so we thought we should do a blog about the thing that scares people most about growing older—Alzheimer’s disease and the other disorders that lead to dementia. 

So you’re in the doctor’s office for an annual physical and the doctor says three words, for example, ball, flag, tree, and asks you to remember them.   Or asks you to subtract 7 from 100 and then continuing subtracting 7s.  You know what’s going on.  You are being tested on the kinds of tests used to screen for dementia.  So are you feeling a little anxious about how you will do?  It is probably no surprise that anxiety is likely to make it harder for you to do those tasks.

A new study done by a French and American team of researchers shows that giving people instructions that increase their fears about how they will perform on a dementia screening test leads to poorer performance on the tests.  In the study, a sample of community living adults who were 75 years old were given two tests that are widely used by doctors and other health professionals to screen for dementia and for Mild Cognitive Impairment, the Mini-Mental State Exam (MMSE) and the Montreal Cognitive Assessment (MoCA). 

If participants were told they were taking a test that older and young people performed differently on, then about half of them scored on the impaired range.  If they were told that older people and younger people did about the same, between 5 and 15 percent fell in the impaired range.  Before they were given the second test, the investigators gave new instructions to the people who had previously been told that they might do more poorly because they were older.  Now they were told that the second test was one that young and old did equally well on.  As a result, their performance improved.

The take home message is if you scare 75 year olds before giving them a test, up to one half will show some impairment.  But if you give them neutral instructions, the actual number that have impairment is between 5 and 15 percent, depending on the test.  This leaves a huge chunk of people who could be misdiagnosed.

When Judy was in private practice doing neuropsychological testing for dementia, she felt strongly that it was important to err on the side of under-diagnosis.  If she had any doubt in the testing, she felt that giving people reassurance would help them worry less, which could improve their everyday performance.  She would arrange for re-testing in a year, and told clients it could lead to three possible outcomes, two of which are good.  A person could get better or stay the same, which are both good outcomes indicating they do not have dementia.  If they declined, it was important to consider how much of a decline was shown before concluding it was dementia.  There can be a little bit of age-related decline that is not early dementia.  In other words, she believed it was unethical to conclude that someone had dementia without being 100% sure. 

From the beginning of our careers, we have seen people who were wrongly diagnosed as having some type of dementia.  Mild Cognitive Impairment is an even fuzzier concept.  Many health care professionals regard it as the first stage of Alzheimer’s but there is increasing evidence that as many as 53 percent of people who are given the diagnosis do not have dementia.  These false positive findings may be due to many factors, such as medications, transient health problems, or as this study showed, just the perceived threat that the test holds can lead to anxiety which leads to poor performance.

The Mild Cognitive Impairment category has become popular because of an emphasis on early detection of Alzheimer’s.  The argument goes that a treatment will only be effective early in the disease, before a lot of the damage to brain neurons occurs.  But efforts at early detection raise the risk of false positive diagnoses, which can cause considerable anxiety and potentially could lead to people trying treatments for a disorder they do not even have, and that are not without their own dangers.  Alzheimer’s is a scary and awful disease.  Efforts at detection need to be tempered by an awareness of the limits of current tools for diagnosis. 

Happy Halloween.


Mazerolle, M., et al., (2017).  Negative aging stereotypes impair performance on brief cognitive tests used to screen for predementia.  Journals of Gerontology: Psychological Sciences and Social Sciences, 72, 932-936.  doi:10.1093/geronb/gbw083

No comments:

Post a Comment