Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

npr.org

Post reply on HN
Print view View original

21–30 of 77 posts

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#21

Post by cogman10 »

jondea wrote: post #13
cogman10 wrote: post #11

Earlier quoted context omitted.

But what if, for example, she's just sensitive to the smell of fecal matter and these people tend to have loser poops? Now is she detecting parkinson or is she detecting IBS or someone that ate something spicy or drank milk while being lactose intolerant. The issue is the one of the false positive and bayesian statistics. If she's detecting something that has a bunch of common causes then it's not really helpful to r…

I'm not an expert, but a very quick search showed a meta analysis[1] which considers the false positives of using volatile biomarkers as a diagnosis. The original paper[2], of which Joy is co-author has a much smaller sample size, but also has a control group to measure false positives. Again, I'm not an expert, but from personal experience I know that Parkinson's can be hard to diagnose definitively until there are…

The science direct link isn't working for me.

But here's the problem as I see it. Parkinsons has an occurrence rate in the population of 0.1%. If there are conditions which cause the same smells as Parkinsons and they are more common in the population (1%, 5%, 10%) then this test all the sudden becomes very not useful because even at 1% occurrence rate in the population it's already 10x more likely that you have that condition rather than Parkinsons. That's the confounding problem. And a different comment here pointed out there are conditions that also seem to have exhibited the same smells.

Who knows, perhaps this is still worth it, but for an n=30 study, this is basically nothing to consider. The group size is simply way too small.

BTW, Medical media reporters really should have a "No reporting on studies with n < 500" rule. These sensational studies are always preliminary on really low population groups. I'd love to see the meta analysis to know how many studies it's lumped in and how big those are, though.

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#22

Post by shermantanktop »

BurningFrog wrote: post #19
patientzero wrote: post #7

Earlier quoted context omitted.

If the goal is early diagnosis and the separate detections aren't getting confounded, why does it matter what parallel chain of causation leads to Parkinson in the patient and a correlating reading in the nose or other test? If no one in a normal state has the same mix of fear, anger and confusion and this leads to a microbial change around sweat glands, then that is a valid test of greater accuracy than many existin…

In the tests, she's presumably smelling people known to have the disease or not, and maybe she can pick up on that knowledge through subtle social cues. Impressive in itself, but that's useless for diagnosing people who don't know they have a disease, which would be the medical breakthrough.

No presuming necessary. In the article, it describes a test involving smelling t-shirts in boxes.

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#23

Post by dgan »

Anecdote : i can totally smell when my testosterone level is high (under doping) because my feet's start emitting a (different than usual) disgusting smell. Definitely less useful than smelling Parkinson, but still kinda interesting !

Edit: might be related to all (or some) those different esters in sustanon

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#24

Post by nradov »

randcraw wrote: post #10
wolverine876 wrote: post #8

They didn't mention looking for other people with the same ability. Maybe other or many or most people can do it, if they know what to look for. If I smell something bad, I never consider that it might be a disease.

If a human can do it, a dog can too, since their noses are so much more sensitive than any human's. I can imagine dogs reliably sniffing out many diseases, then this becoming a standard lab assay, or at least a component thereof.

When you feel sick, go get a "Lab" test.

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#25

Post by jamestimmins »

According this 2022 piece from the University of Manchester, it seems there have been some notable updates on the research.

By using mass spectrometry, a technique that measures the weight of molecules, they have found that there are distinctive Parkinson’s markers in sebum – an oily substance secreted from the skin.

This breakthrough has led them to develop a non-invasive swab test that can, in conjunction with the onset of early Parkinson’s symptoms, identify Parkinson’s disease with around a 95% accuracy. What’s even more astounding is the speed with which the test can return a result; around 3 minutes under lab conditions.

https://www.manchester.ac.uk/discover/news/a-nose-to-diagnos...

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#26

Post by londons_explore »

Beijinger wrote: post #18
jbandela1 wrote: post #6

> But Joy's superpower is so unusual that researchers all over the world have started working with her and have discovered that she can identify several kinds of illnesses — tuberculosis, Alzheimer's disease, cancer and diabetes. The story for diagnosing Parkinson’s sounded plausible until this sentence. With Parkinson’s, you could imagine that she had some sort of sensitivity in her smell to a certain biomarker. Now…

Why should she not be able to detect some kinds of cancers? Some dogs can. In the end, all this should not be so difficult. Take the head space, then do MS of a bunch of people with these diseases and the head space and MS of healthy people as a comparison. The delta gives the disease.

I'm not sure any of today's mass spectrometers yet can match human smell in sensitivity, at least to some scents with larger more complex molecules.

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#27

Post by throwawaymaths »

londons_explore wrote: post #26
Beijinger wrote: post #18

Earlier quoted context omitted.

Why should she not be able to detect some kinds of cancers? Some dogs can. In the end, all this should not be so difficult. Take the head space, then do MS of a bunch of people with these diseases and the head space and MS of healthy people as a comparison. The delta gives the disease.

I'm not sure any of today's mass spectrometers yet can match human smell in sensitivity, at least to some scents with larger more complex molecules.

Mass specs can detect down to the ten thousands? IIRC or so molecules.

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#28

Post by bobthepanda »

randcraw wrote: post #10
wolverine876 wrote: post #8

They didn't mention looking for other people with the same ability. Maybe other or many or most people can do it, if they know what to look for. If I smell something bad, I never consider that it might be a disease.

If a human can do it, a dog can too, since their noses are so much more sensitive than any human's. I can imagine dogs reliably sniffing out many diseases, then this becoming a standard lab assay, or at least a component thereof.

Also, assays cost less money than dogs which cost less money than human specialists.

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#29

Post by LorenPechtel »

jbandela1 wrote: post #6

> But Joy's superpower is so unusual that researchers all over the world have started working with her and have discovered that she can identify several kinds of illnesses — tuberculosis, Alzheimer's disease, cancer and diabetes. The story for diagnosing Parkinson’s sounded plausible until this sentence. With Parkinson’s, you could imagine that she had some sort of sensitivity in her smell to a certain biomarker. Now…

I read the article as saying she can tell them apart, not merely sorting them into healthy/sick.

And I wouldn't be surprised if things like "cancer" were actually a confounder (I'm thinking along the lines of detecting the body's reaction rather than the tumor itself)--but it's still useful information. They've already used her information to find a albeit imperfect test for Parkinsons. What if you had a similar test for cancer? It would tell the doctor to start looking in fashions they would not do for the general population.

Re: A woman who can smell Parkinson's is inspiring research into diagnosis (2020)

#30

Post by londons_explore »

throwawaymaths wrote: post #27
londons_explore wrote: post #26

Earlier quoted context omitted.

I'm not sure any of today's mass spectrometers yet can match human smell in sensitivity, at least to some scents with larger more complex molecules.

Mass specs can detect down to the ten thousands? IIRC or so molecules.

But I don't think they can do that at the same time as having trillions of some other uninteresting molecule like water in them.

It's basically a dynamic range problem.

Post reply on HN