The accuracy of this test is nowhere nearly good enough to do population-wide screening. The clinical setting for this test is memory clinics in which Alzheimers is already relatively highly likely differentially, and even there you're going to get a surprising number of false positives.

(There's enough info in the supplemental link on this page to have an LLM do the Bayes math for you.)

This again?

The test is optional. Feel free to skip it.

Tell 50 million people they’re likely to have Alzheimer’s then tell them where to donate towards a cure, or treatments to slow it by a decade.

I would personally want to know as early as possible, so I could get my affairs in order and register my wishes around end of life care and euthanasia while I am still recognised as having full mental capacity.

It's also better for people around the Alzheimer's patient, as it will let them understand why someone's personality and behaviours may be changing, and possibly let them be bit more forgiving of such changes. It will also give family more time to plan and understand the health and community services and support are offered wherever they live.

There are more personal practical reasons too.

Even though it cannot be reversed or eradicated (yet, let's hope) detection can allow individuals to adopt interventions that help either adjust their lives to better cope with its progression or help mitigate some of the detrimental behavioral consequences. In addition, if you have family to care for it may be impetus to get certain things in order for them before later stages of the disease, etc. It's horrible and bleak, but I could certainly see why one might want to know.

In the lucky case, it can also relieve anxiety. Even though false negatives may still be possible, receiving a negative detection might give people who have anxiety about certain symptoms relief, since they can rule out (rightly or wrongly) a pretty severe disease.

If the patient still has periods of lucidity but the disease is suspected to be advancing, knowing they have it could prompt them to get their legal affairs in order.

It's very useful to understand what you're struggling from even if it's not curable. It explains your symptoms, your experience and help you understand what you're going through. Understanding that you're suffering from something incurable is also helpful in not looking for other ineffective methods to cure a mysterious illness.

Having struggled with hard to diagnose health issues before, I can’t emphasize enough how much of a relief it is to put a name on the disease that is causing you so much harm.

It is frankly shocking to think disease diagnosis would be a useless thing

I know two people who have been taking the new monoclonal antibody treatment for it. One who was a bit further along when she started, and did not show any significant improvement. The one who started while she was still in the early stages has completely arrested her descent. She hasn't recovered much of what she already lost, but she's still able to live independently and enjoy life, and her mental acuity scores are (slightly) better than they were last year. That's a hell of a thing.

If a loved one is suffering from this, this diagnostic would allow for interventions such as guardianship to assume financial and logistical responsibility for them with less subjective decisioning based on observations alone.

there are treatments that can help slow progression, especially if it's found early.

I assume this is hugely beneficial for research on intervention methods, not for treatment. I think everyone is focusing on "I'd rather know" but imagine if you could get larger populations with a diagnosis earlier on, how impactful that would be for testing an intervention?

> why we would want to detect Alzheimer’s

At a personal level, I've been through this with my grandfather.

I want to know. My family wants to know. I want to prepare because there are things I want to do today that I know I won't be able to do in the future.

In many ways, it's just like many terminal cancer diagnoses. You're going to lose that person, but you have some time.

Well, the AI CEOs are telling we will have AGI in ~5 years, so with millions of agents with AGI this thing should be sorted soon ;)

Most people get a dementia (or related) diagnosis after they are deep enough in it so that they cant do much about it or get their affairs in order.

My grandfather had a "fall" at work, he then left that job, and held down 2 more engineering jobs before he was diagnosed with a stroking condition and subsequent dementia. I got the distinct impression he thought he had more time, but rapidly declined.

If he knew he was short of time before his rapid decline he probably would have done things differently. Like not buying a house he would later have to sell to pay for aged care.

If he knew he was at risk of a workplace accident he probably wouldn't have worked as an after hours safety engineer at a major treatment plant, where if the worst had happened he could have endangered others.

Being able to know someone's risk factor would be important for how we treat elderly people. I know someone who is 85 and super sharp (previously worked as a corporate accountant and banker), they still have a better memory than a lot of 40-50 year olds, and yet they are constantly harassed by eldercare "agents" for the state because whenever they make a investment decision that is even slightly questionable they get reported to the state by the bank. Sometimes the bank refuses to authorize transactions. If they could conclusively prove they aren't at risk I think they would be left alone much more often.

As per the article, the test is used in conjunction with clinical diagnosis, not instead of.

This isn't a predictive test that someone could take in early life.

It's used to refine clinical diagnosis after patients present with cognitive severe decline.

By the time someone gets this test, they have severe problems. The purpose of this test is to assist with the right diagnosis.