'Ideal biomarker' detects Alzheimer's disease before the onset of symptoms | Hacker News Reader

'Ideal biomarker' detects Alzheimer's disease before the onset of symptoms

eurekalert.org

26 pointsnzp19 comments

This sounds almost too good to be true. It's published in a lower impact journal so I'm wondering if the sample size was very small. Also, how did they confirm the 'topography of the pathophysiology' (where the disease is) without taking people's scalps off?

Looks like n=20 from skimming. MEG and MRI scans were used.

http://onlinelibrary.wiley.com/doi/10.1002/hbm.23724/epdf

Yep. Far too early to get excited.

The article claims this test will promptly be used clinically. Diagnosing Alzheimer’s while there is no cure or treatment available is useless. If used, the test unnecessarily burdens patients sooner. I can see the importance of this test in helping to find the root cause of Alzheimer’s, but I can’t see why this test would be used clinically while we can’t do anything about Alzheimer’s.

Useless to whom? It would be somewhat arrogant to suppose that some people would not prefer to make arrangements for their family and themselves in the light of a diagnosis. Might they not have one of the 'X things to do before you die' books and feel like following it up while they have the opportunity? Moreover it may be that new treatment arrives that optimally only works in the very first stages as detected by this test.

I agree with your last point. An early detection tool can help find a treatment/cure that works before the disease progresses too far. Again, I see the use for research purposes. While writing my original comment, I specifically had WHO's Wilson criteria in mind (http://www.who.int/bulletin/volumes/86/4/07-050112/en/). The 2nd point requires that there needs to be a treatment in order to screen for a disease.

The current time from diagnosis of Alzheimer's to death is about 8 years (with some variability) with a relatively slow progression of symptoms. It's possible that some people may want extra time to make arrangements like you say, but this comes at the cost of living without knowing whether you have Alzheimer's. I've never been in this situation, but I can't imagine that this tradeoff is clear-cut for anyone.

I think my gripe with the article is that it claimed this test will "promptly be used clinically". I seriously doubt this. The article doesn't report the sensitivity or specificity of the test, and we don't have a great sense of how early this test can detect Alzheimer's.

> Diagnosing Alzheimer’s while there is no cure or treatment available is useless.

Until we have better cryopreservation

I don't think that it necessarily is useless. My grandfather is starting to experience memory loss, and he's not sure if he has Alzheimer or not, there is a family history. If he knew, that would make financial planning potentially much easier. He's always talking about whether he should travel now, or leave money in the bank for nursing home care. If he could know, maybe it would hurt, but it would help as well.

I can imagine it would be useful for the development of new therapies to test them on early-stage patients.

   1. Because people want to know for lots of reasons like financial planning or "bucket listing".
   2. The more people who know sooner, the more we might learn about the disease, how it progresses, 
   and the genetics of the people who acquire it.

There's nothing curative, but there's a fair bit of palliative care drugs, esp. for early stage, at this point. Getting on them a little early might mean another year or two of independence which is no small thing.

It might let you plan your suicide while you are still able to.

I'd definitely like to know if my future includes Alzheimer's. At the very least, I'd stop saving for retirement. You say we can't do anything about the disease, but as an individual, I can certainly decide how far I want to let the disease progress.

It seems unwise to assume that we won’t find a cure or treatment in the next n decades.

I wouldn't say it's unwise, but there's definitely a decision to be made.

If I decide to let the disease progress to the point where I don't know my family members and am acting violently, how likely is it that a cure is going to be found that can reverse that damage? I don't think it's very likely and so I would probably choose to die before that point.

Yes, but it doesn’t make sense to avoid saving for retirement.

Given that a number of countries/US states have euthanasia laws on the books, it is definitely an actionable diagnosis at this point.

I wish I could upvote your comment several times over.

One of the commonest fallacies that we carry over from everyday life, over to chronic disease is that early detection followed by intervention will reduce the burden/discomfort/work in the future. We are probably wired for this fallacy, for example in the prehistoric era: detect an impending attack by an invading enemy would have resulted in better survival.

Some non-main stream cancer practitioners postulate that the only reason cancer survival rates seem to have improved over the years is because of earlier detection. A cancer survivor is broadly defined as someone who lives 5 years after detection of the cancer. So in the distance past when detection methods were relatively primitive cancer was detected at the later stages and the patient died quickly there after. Now they live longer after they have been detected because it was detected relatively earlier. The better survival rate is attributed to the treatment regiment, which is not the case. It is just that the window of time between detection of cancer and death of patient has increased.

Anyways, none of this is news to people are understand human nature, there is quite a bit of 'superstition' even in science and medicine.

The same could be said for the Huntington's Disease test, which has been around for a long time.

It's difficult for potential sufferers of Huntington's Disease to decide whether they want the test. Some do and others do not, but most potential Huntington's Disease sufferers are happy that the test is available.

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