
Alzheimer's research in ‘major step’ towards blood test - glaugh
http://www.bbc.com/news/health-28198510
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tokenadult
The article reports:

"Dr Eric Karran, director of research at Alzheimer's Research UK, described
the study as a 'technical tour de force'.

"However, he warned the current accuracy levels risked telling healthy people
they were on course to develop Alzheimer's which may lead to anxiety and
depression."

I just completed the Coursera online course in human behavior genetics. One of
the ways that psychology research can contribute to the hoped-for future of
genomic, personalized medicine is by figuring out how patients will react to
various kinds of personal medical information about possible future outcomes.
Today, there are some genetic tests for Mendelian (single-mutation) diseases
that have a very high reliability, but many patients don't seek those tests,
even if they have relatives who had the diseases, because there isn't much a
patient can do about an incurable disease. People DON'T want to know that they
are sure to die with a grave disease in the next twenty years. People would
rather imagine that they just might live forever.

So if other studies replicate the result of the study reported here, and
perhaps even further refine the accuracy of predicting Alzheimer disease risk
from a simple blood test taken earlier in life, there will still be plenty of
research to do on how to motivate patient behavior in

a) seeking the test,

b) acting on the results of the test in a rational way,

and

c) not piling up other health risks meanwhile.

And of course if this study finding eventually translates through further
research into a deeper understanding of the cause of Alzheimer disease,
leading to a prevention strategy or even a cure for that disease, that would
be wonderful, but there are plenty of diseases that can be reliably diagnosed
without being treatable or even preventable at all. This is a good step
forward, but much work remains to be done to tackle Alzheimer disease and
further prolong healthy lifespan for the patients at risk for that disease.

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Brakenshire
I think the most important use of a blood test wouldn't be for patients, but
for researchers. If you can predict 90% of a cohort will develop Alzheimer's,
you can do much smaller, more powerful trials on interventions.

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SoftwareMaven
Isn't this still too late? On the other hand, there is some early evidence
that a blood sugar meter may be able to be used as an early diagnostic, at a
time when one can do something about it. Keeping blood sugars relatively low,
and, probably more importantly, having relatively long periods of low (but
normal) blood sugars through e.g. intermittent fasting or even
reducing/removing snacks may be the best preventative measure one can take.

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glaugh
Really wish they broke "86% accuracy" into precision and recall.

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icegreentea
Here's the paper:
[http://www.sciencedirect.com/science/article/pii/S1552526014...](http://www.sciencedirect.com/science/article/pii/S1552526014024546)

Re your comment: "accuracy 87%, sensitivity 85%, and specificity 88%"

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skierscott
What does that mean for false positive and true negative?

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icegreentea
Sensitivity is the true positive rate, specificity is the true negative rate.

From the body of the paper, for their chosen test, their False Positive Rate
appears to be 21.2% (100% - 68.8%) and their False Negative Rate appears to be
5.1% (100% - 94.9%). For this type of test, its the false negative rate that
we'll really worry about.

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jarvic
There really is encouraging progress being made in this area (early prediction
of AD) in several different fields. I know of several different groups who are
using imaging instead of blood tests to predict conversion of MCI to AD as
well. A lot of it is using the data being collected by ADNI:

[http://www.adni-info.org](http://www.adni-info.org)

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leorocky
I guess the major benefit is for people who do not actually have alzheimers
being falsely diagnosed, but early detection doesn't help in any way for
people who do have it, right? I'm not sure I'd want to know until it was
unavoidable.

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drcode
I have a hard time understanding why people wouldn't want to know what's in
store for the future. Even if it's unavoidable, there's still lots you can do
in terms of making best use of the time remaining to you.

~~~
drcross
Protip- We are all going to die so make the best of it in any case.

~~~
drcode
Certainly can't argue with that

