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Alzheimer Disease: How Soon Would You Want To Know?

The views expressed are those of the author and are not necessarily those of Scientific American.


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Cartoon of Alicia meeting a new doctor who wants to screen for Alzheimer disease on her 25th birthdayHave you been forgetful lately? Any difficulty concentrating? Trouble recalling names?

Answer “yes” to even one question like that, and there are some who want you to head to a clinic for memory screening. And it’s not because there is a good new treatment for dementia. If only there were.

Therapy for dementia remains a bleak landscape. And while we have a sense of some risk factors that could be modified (like smoking), there’s nothing solid enough to be an early prevention strategy, either.

Nevertheless, people are taking lessons from the cancer awareness-raising playbook to encourage and prime us towards believing we can prevent Alzheimer disease, and accept early – even very early – detection.

It seems to me we’re not prepared for this.

If we’re diagnosed with Alzheimer’s or any dementia, almost all of us would want to know it: somewhere around 90%, according to a recent study and systematic review. But that’s not the same as wanting to be diagnosed early: there the numbers in favor drop steeply.

At the moment, the odds are that most of us won’t ever have to cross that bridge ourselves. And as people get generally healthier, the chances of a person at average risk getting Alzheimer dementia could fall, too. But a downside of early detection campaigns is a wave of false positives. They’re only worth it when the benefits outweigh the inevitable harms.

Early detection is intuitively compelling when faced with a dreadful, progressive disease. Get in and do something before it’s too late. But as I’ve discussed here before, hope can prevail over reason.

Sketch of lead-time bias

Lead-time bias: How early detection shifting the diagnosis needle can lengthen "disease survival rate" without lengthening life

Appearances can be deceptive. When you start expanding the pool of people who are diagnosed, it means you are diluting the truly sick with many who were never going to get sick. That automatically seems to improve outcomes, feeding the impression that people are being helped.

In the case of dementia, timely diagnosis is what most of us seem to want. To know before not knowing has caused suffering around us, and while we still have time to make arrangements.

That’s not what’s driving the push to very early detection, though. The goal of very early detection is to find people so early in the development of the disease that they are not yet ill – and ultimately, about 25 years early, in mid-life, not old age. For those with a genetic susceptibility, possibly earlier than that.

But not only don’t we know if Alzheimer disease can be slowed down in its early stages, we don’t know yet how to tell who will get it. Even the best estimates are still quite vague. For people with mild cognitive impairment (MCI), roughly 20-40% will go on to dementia – but roughly 10-40% will return to normal cognition. Brain scans and blood or cerebrospinal fluid tests for dementia biomarkers aren’t accurate enough early on.

Neither the US Preventive Services Task Force nor the UK National Screening Committee recommend screening older adults for MCI or dementia. And most advocates of early detection are doing so to support research, not widespread screening.

But there’s strong advocacy to do it now – such as the “memory screening” clinics I mentioned earlier. And in the UK, another part of the National Health Service targets some groups of people for dementia for (including people with cardiovascular disease from the age of 60).

Image of etching

Schande (Shame) by Max Klinger

Margaret McCartney, a doctor in Glasgow and author of The Patient Paradox, wrote in the BMJ last year: “The rush to ‘early’ diagnosis has missed crucial dialogue. Earlier than what? Why? We should aim for timely, consensual diagnoses as part of a dialogue…A negative dementia screening result does not mean people do not have to plan for the future.”

Early dementia diagnosis is more than a double-edged sword. People with dementia and their caregivers point to another concern: will a growing belief that the disease is preventable increase the burden of shame and stigma? That’s a reasonable concern, according to Claire Scodellaro and colleague. The stigma of Alzheimer collides with the stigma of ageing – and both stigmas hit women harder.

According to Elizabeth Peel’s research, media coverage of Alzheimer disease and its prevention is heaping fuel on the stigma, and ushering in the belief in lifestyle changes that can “keep dementia at bay” – a precursor to victim-blaming.

Cartoon of Alicia thinking she needs another doctor

Keeping up this panic-blame-hype cycle serves some interests. But we have to turn it around.

In a risk assessment of the hazards of early detection, Steve Iliffe and colleague describe the diagnosis of dementia as “a portal into the world of ‘mental incapacity’ in which behavior becomes interpreted as a sign of the disease, and forgetfulness is itemized and monitored.”

We shouldn’t rush people headlong through it.

The push to re-define cognitive problems as “predementia” is part of a broader problem of expanding disease by creating “prediseases.” This variant, though, is one of the worst.

~~~~

Close-up photo of a tree's bark with shadeLinks to great literature on Alzheimer disease, personal experiences and a conversation that followed this blog post, here in a Storify.

More from me on early detection in my post on The Prevention Illusion: A Tragedy in Five Parts. Browse through all my posts at SciAm on related themes.

The cartoons are my own (Creative Commons License): more at Statistically Funny.

More on Schande (Shame), an etching by Max Klinger (1857-1920). (Included here via Wikimedia Commons / the Google Art Project.)

The photo of the tree’s bark and shade is my own.


* The thoughts Hilda Bastian expresses here at Absolutely Maybe are personal, and do not necessarily reflect the views of the National Institutes of Health or the U.S. Department of Health and Human Services.

Hilda Bastian About the Author: Hilda Bastian likes thinking about bias, uncertainty and how we come to know all sorts of thing. Her day job is making clinical effectiveness research accessible. And she explores the limitless comedic potential of clinical epidemiology at her cartoon blog, Statistically Funny. Follow on Twitter @hildabast.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. rshoff2 10:56 am 08/25/2014

    Right now. I want all the bad news right now. Why? Because it’s knowledge. I would at least know where to focus my efforts and how to plan my future. I also want to be able to take advantage of early treatment as it becomes available. We must take responsibility for ourselves. To put your head in the sand is to trust that “the system” -comprised of good people with their own problems and priorities- to meet your future needs as the become apparent. I’ve learned, the system runs over you while tossing a bone if you happen to be mainstreamed. Otherwise, it just runs over you to be swept to the side to make room for others.

    Of course it would be depressing and complicated. But knowledge is power over ourselves.

    Link to this
  2. 2. Hilda Bastian in reply to Hilda Bastian 7:23 pm 08/25/2014

    If we knew how to provide an answer that was reliable, it would be a different conversation. Is it knowledge, rshoff2, if it’s about as likely to be wrong as right?

    Link to this
  3. 3. HildyJ 7:58 pm 08/25/2014

    As one for whom dementia is a very real, and potentially probable, possibility – my father and his father both suffered dementia, Alzheimer’s in the case of my father – I will wait for a more definitive test. I want a test that gives me the number of years I have left before I am incompetent so that I can plan the end of my life, depending on the options available at the time.

    Link to this
  4. 4. rshoff2 1:36 pm 08/26/2014

    Thank you for pointing that out Hilda – That is so very true and something that I failed to realize clearly. But are we not given the right to determine what may or may not be true and where we would like to make our own mistakes? But it’s circular, because you are still right, if it is not reliable then it is not knowledge.

    But does it have to be perfectly reliable, or just mostly, or almost reliable before we get to include it as a possibility in our personal knowledge base. Who decides when we get to choose?

    I’m going through some of those thoughts on my own minor age related issues that may become major issues in a decade or less. Or will they? To what extent can I access the medical system to try to offset those (possible) adverse future events.

    I truly appreciate being able access to information and expertise such as yours. Thank you for making it available in your blog and helping navigate concepts that are counter-intuitive at times.

    But in support of your article, I have had DNA tested via a consumer organization and found out that I have the genes for blond hair. Amazingly, my hair is not blond, it is in fact dark brown. But they were correct in my eye color and some other unusual characteristics. But still, what happened to the blond hair? So, if they should say I won’t get cardiovascular disease but will get Alzheimer’s, is it like the eye color (correct) or the hair color (completely wrong)?

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  5. 5. Hilda Bastian in reply to Hilda Bastian 8:41 pm 08/26/2014

    Interesting analogy, rshoff2. And at the heart of the current debate at the FDA about just those kinds of tests, and how valid they need to be. When something isn’t potentially actively dangerous, people can get it and use it if they want to – but the question of regulation does come in at some point, especially when people are making the kinds of claims that we as a community have decided need to have some independent, highly expert scrutiny. And it comes into play, too, when deciding how public money could be spent.

    I got into this field originally as a health consumer advocate – representing the public in many community-level decision-making processes about these kinds of issues. I still think that’s part of how things need to be done (experts of various sorts, including from the community, working together). A strong support for people’s rights, with a strong process for determining the public interest alongside it.

    Those two things – it depends how dangerous it is, and how we go about the process of deciding when something needs to be regulated or public/expert recommendations made – would be how I’d approach your question, “who decides when we get to choose?”

    How reliable does it have to be depends too – on the context, and individual values and tolerance for uncertainty and risk-taking. I’ve made – and continue to make – many personal decisions that most others would think are reckless. And other decisions that others might find over-cautious. Sometimes, my decisions aren’t even consistent with my own values, never mind anyone else’s.

    I think, though, the complexity of these things is partly why I feel so strongly about the need for getting as objective and unbiased as it’s humanly possible to get, in evaluating the pros and cons of an issue. Be that health, social, public policy – many areas of life. We need good ground rules for how we measure and test what can – and should – be measured and tested. It mightn’t be relevant at all to our decision making – or it might make the decision harder. But it might help us live more easily with the decisions we make, if we know we did the best we could manage at the time as we muddled through our lives and decisions. Getting into dire straits because people with vested interests steered us astray makes it harder to be at peace with it.

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  6. 6. Hilda Bastian in reply to Hilda Bastian 9:32 pm 08/26/2014

    Hildyj, thanks so much for that. I hope it does get better. Definitely the options, and the test too – including being able to ease anxiety over symptoms that don’t need to be a reason to worry. Hope you never need it, though.

    Link to this
  7. 7. Hilda Bastian in reply to Hilda Bastian 1:19 am 08/27/2014

    Rshoff2 and Hildyj: I quoted your comments in a Storify, and hope that’s ok. (You can email me over the contact form at this blog.)

    Link to this
  8. 8. Stagnaro 10:34 am 08/27/2014

    Unfortunately, the concept of AD Inherited Real Risk, bedside recognized from individual’s birth, and removed by Quantum Therapy, is not jet sufficiently known and widespread among physicians.
    Marco Marchionni, Simone Caramel, Sergio Stagnaro. Inherited Real Risk of Alzheimer’s Disease: bedside diagnosis and primary prevention.Frontiers in Neuroscience, in http://www.frontiersin.org/Aging_Neuroscience/10.3389/fnagi.2013.00013/full [MEDLINE]

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  9. 9. hkraznodar 5:52 pm 09/4/2014

    We all die. I just want to still be enough of me to know it. Alzheimer’s runs in the family on my dad’s side and heart disease on both sides. I’ve already had 1 heart attack so I figure the odds are pretty high that I’ll get Alzheimer’s. If there was any treatment at all that offered some hope I would want early detection. If there was some way I could participate in a study on early detection and intervention I would. I’m not aware of any efforts at early detection or early intervention.

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  10. 10. Hilda Bastian in reply to Hilda Bastian 7:50 am 09/5/2014

    Hkraznodar, I’m not sure what country you’re in, but I’ll start with the US. If you are interested in seeing whether there are clinical trials you could join, trials that are recruiting participants can be found (click on bold for links): at ClinicalTrials.gov and also at the NIH – more details about other studies and research centers from the NIH are here. You can find registries of trials, that also include trials that are recruiting people, from other countries at the WHO. And here’s the link to the specific organization I was linking to in my comment on this in the post: AFA. Hope that helps – and best of luck!

    Link to this

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