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If you're new to this blog and want some context for it, read this post from the day I announced my Alzheimer's disease and this post about the day I announced I had lost it. For more info, visit my website with my autobiography and all blog entries in chronological order for easier reading to catch up. There's also a sermon on the spiritual lessons I've learned through this journey through my damaged mind.

Tuesday, February 25, 2014

Subjective Cognitive Decline (SCD)

Washington DC

As a physician, I always told my older patients that a decline in memory as they aged had nothing to do with the risk for Alzheimer’s.  I have repeated the same thing in this blog several times, for instance, here.  Apparently, I’ve been wrong.

As the results of a number of research studies presented at the Alzheimer's Association International Conference (AAIC) in July 2013, get around, they will worry a lot of older people and bring them to their doctors for testing.  According to the studies, people with subjective complaints of cognitive decline (for example, memory loss) but no objective findings (ie, their tests for impaired thinking are normal) are considerably more likely to progress to mild cognitive impairment (MCI) or dementia than people who have no such complaints.  In plain English, if you think your memory is getting worse as you age, you have good reason to be concerned about Alzheimer’s or other dementia even if your doctor tells you you’re fine.

These findings are in complete contradiction to what most physicians believe, which is that memory complaints are a normal sign of aging and have nothing to do with the Alzheimer’s. 

One of the doctors interviewed acknowledged that “you clearly don’t want to worry everybody who’s aging,” but, it seems to me, since so many people experience worsening memory as we age, these findings are going to worry almost everybody.  I can just see the rush to doctors’ offices.

Each of these studies has a different design.  Some look at people who have already come to their doctors with symptoms; others are more reliable studies of the unselected general population.  Some include data about whether family or friends notice the symptoms; others don’t.  At least one study includes autopsy results (the only way to definitively diagnose Alzheimer’s).  One study includes progression to MCI as well as to dementia.  Another includes MCI or dementia from any cause, not just Alzheimer’s.  The advantage of these multiple designs is that the results are less likely to be due to some flaw in the design.  The disadvantage is that none of the studies has been explicitly replicated, which is usually necessary to draw valid conclusions. 

But all point in the same direction: if you think your  memory is getting worse (or you’re having trouble with other kinds of thinking), you have a good chance of progressing toward something more serious.  One study suggested that your chances are about two out of three.

As usual, these kinds of studies raise more questions than they answer.
  • Is your risk increased (and by how much) if your PET scans (like mine) are normal?
  • If the only problem you have is remembering names, how serious is that? 
  • If your only symptom is not being able to find the right word exactly when you need it, is the risk of progressing to MCI or dementia higher?
  • Is the real problem only with Alzheimer’s or does it include other causes of cognitive impairment?
 It will be interesting to see how these findings affect both patients who worry about their memory and doctors who care for them.


  1. I try not to worry about my word substitution since I was still quite young when I wrote "radio controlled" when I meant "automatic pilot." But I have noticed this word substitution happening more frequently lately so something is going on in my head. Still I am not worried enough to do any testing yet. But, I'm glad to have someone who edits my speech when I make that type of mistake.

  2. Wow. This one is a bummer. I am glad you wrote it, because I want to know the truth, but just wow. And Rats. And bummer. I will have to work harder at keeping my memory going instead of just being lazy and saying that it doesn't matter. Clearly, it matters. Bummer. But thanks!

  3. These research findings are interesting. But from a practical perspective, what I (a geriatrician & internist) tell people is that dementia down the line is always a possibility, and for now I encourage them to watch for signs that their function is being impaired. (I like the Alz Association's 10 signs.)

    I also encourage them to get enough sleep and avoid anticholinergics, benzos, and psychocactives.

    1. It's easy to forget that what studies like these do is change our understanding of the odds, of the chances, of the statistics. As you say, "dementia down the line is always a possibility" and these studies don't change that simple fact.

    2. In truth, given how old most of my patients are, dementia down the line is a pretty likely possibility!

      I once had a clinical teacher who emphasized that much of what we can do for people is acknowledge the uncertainty and how hard it is to not know exactly what's going to happen in the future.

      And then help them focus on some things they can do now. So, that's what I try to do, but easier said than done.

      I've been referring people to your blog as I think it's a nice way for people to get a feel for all the uncertainty that surrounds MCI or early dementia. More testing doesn't always bring us the answers we long for :(

    3. I agree with your comments that the medical professional's job under these circumstances is to help patients deal with the uncertainty. Too common is the expectation that doctors should be able to treat almost anything ... or at least tell us what we have. Too often It's just not true. And one of our responsibilities, as you say, is to help the patient through -- whether it's something serious, something that will get better in a few days, something we can't diagnose yet. And, as you also say, perhaps the best way of helping someone get through, especially getting through uncertainty, is to focus on what they can do ... even if it won't "cure" anything.


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