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

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

#11

Post by cogman10 »

patientzero wrote: post #7
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…

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…

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 run a suite of tests to find an underlying problem on everyone that smells the same.

A fever can be a sign of cancer, but it's also a sign of the flu. Should we check everyone with a fever for cancer?

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

#12

Post by inglor_cz »

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…

That might be just an imprecise formulation by the journalist.

Smelling tuberculosis seems plausible to me, it is a disease of the lungs.

General cancer probably no, but I have repeatedly read comments by oncologists that sarcoma, specifically, has a distinct smell.

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

#13

Post by jondea »

cogman10 wrote: post #11
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…

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 serious symptoms. This test may be relatively poor but still be useful as a piece of evidence.

[1]: https://www.sciencedirect.com/science/article/abs/pii/S03038...

[2]: https://pubs.acs.org/doi/full/10.1021/acscentsci.8b00879

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

#14

Post by zeristor »

inglor_cz wrote: post #12
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…

That might be just an imprecise formulation by the journalist. Smelling tuberculosis seems plausible to me, it is a disease of the lungs. General cancer probably no, but I have repeatedly read comments by oncologists that sarcoma, specifically, has a distinct smell.

Makes me realise there is no real way to notate a smell.

How do people even get a handle on what a smell is, and how personal an experience is it.

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

#16

Post by rpgwaiter »

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 bet most (type 1) diabetics could smell other diabetics if they were trying. High blood sugar especially changes your body odor a ton. You sweat a lot more sugar for your skin bacteria to digest.

Not to discount the woman or the article, we should totally be researching this stuff

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

#17

Post by kseifried »

zeristor wrote: post #14
inglor_cz wrote: post #12

Earlier quoted context omitted.

That might be just an imprecise formulation by the journalist. Smelling tuberculosis seems plausible to me, it is a disease of the lungs. General cancer probably no, but I have repeatedly read comments by oncologists that sarcoma, specifically, has a distinct smell.

Makes me realise there is no real way to notate a smell. How do people even get a handle on what a smell is, and how personal an experience is it.

Aroma and smell training kits exist for people into wine, beer and so on: https://aromaster.com/

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

#18

Post by Beijinger »

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.

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

#19

Post by BurningFrog »

patientzero wrote: post #7
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…

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.

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

#20

Post by OkayPhysicist »

rpgwaiter wrote: post #16
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 bet most (type 1) diabetics could smell other diabetics if they were trying. High blood sugar especially changes your body odor a ton. You sweat a lot more sugar for your skin bacteria to digest. Not to discount the woman or the article, we should totally be researching this stuff

Anybody can learn pretty quick to smell diabetics. Low blood sugar leaves one's breath bitter and metallic, high blood sugar causes fruity, sweet breath. It's extremely obvious if you're at all close to them.
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