
A woman who can smell Parkinson's disease - dan1234
http://www.bbc.co.uk/news/uk-scotland-34583642
======
bazillion
This reminds me of when I was in the Navy -- at one point I had lived with
hundreds of other guys in a ship's berthing and at another duty station I
mentioned to a coworker that I could determine someone's race from their
sweat. Of course, they called bullshit on that statement (as I'd imagine most
on here would) and we tested it out with 4 guys (1 black[1], 2 white[2], 1
hispanic[3]) who sweated into the same size shirts, and I was able to identify
them with 100% accuracy. Another time, I walked into a cubicle, wrinkled my
nose, and said "Man! It smells like an old deck of cards in here!". One of the
guys standing next to me then pulled out a rather well-played-through deck of
cards out of his pocket.

One of the reasons people give for the difference in smell are the difference
in foods that different cultures eat. I definitely know this is not the case,
as everyone on that ship was eating the exact same food, and their smells were
extremely distinct.

I understand that lack of science applied to my specific anecdotes, but I
think there's something to be said for having a keen sense of smell, since
people are already geared towards smelling other people's sweat to determine
immunocompatibility[4].

[1] A black person's sweat is the one I can identify with absolute certainty,
as it's completely unmistakable for anything else

[2] A white person's sweat smells like a distinct type of onion to me

[3] I couldn't really identify his race if it were just this shirt, but had
that one by process of elimination.

[4]
[https://en.wikipedia.org/wiki/Major_histocompatibility_compl...](https://en.wikipedia.org/wiki/Major_histocompatibility_complex_and_sexual_selection#MHC-
mediated_mate_choice:_case_studies)

~~~
JoeAltmaier
I hear anecdotally that Japanese think Americans smell like butter.

~~~
lovemenot
It is frowned on now, but in former decades some uncouth Japanese would say
"Cheezu nioi" (smells like cheese) when encountering a foreigner.

~~~
tim333
Though I think that's mostly diet related - Japanese don't really do dairy.

------
IkmoIkmo
The thing that most surprised me were the odds that a person in the control
group (no parkinson's), actually did have parkinson's (diagnosed early
according to the woman) and was diagnosed later to indeed have parkinson's.

After all, the prevalence is 0.3% in the general population. The odds at least
one of the six in the control group had parkinson's is around 2% (even less
considering it's already a filtered audience in a way). Not impossible but
very unlikely, which incidentally makes her insistence of that single
particular person to have PD all the more interesting.

There's definitely something there, looking forward to more testing.

~~~
eterm
I don't understand the phrasing there, "She was adamant".

If it was a controlled test, why should she need to be "adamant" about
anything, surely she would have merely identified it.

~~~
IkmoIkmo
I guess after the test they told her the results (i.e., you're wrong on 1
person because he's in the control group and doesn't have Parkinson's), at
which point she insisted that he smelled the same as the others, and then the
journalist wrote that up as 'she was adamant he had Parkinson's'. Or she
really did fully believe in her sense of smell as an ability to detect
Parkinson's without doubt, at which point it as much sense for her to say a
person has Parkinson's as you to say the sky is really blue because your eyes
tell you and the journalist simply relayed that. There's various readings of
the phrase that can make sense.

------
Mz
_" Her accuracy was 11 out of 12. We were quite impressed."

Dr Kunath adds: "She got the six Parkinson's but then she was adamant one of
the 'control' subjects had Parkinson's.

"But he was in our control group so he didn't have Parkinson's.

"According to him and according to us as well he didn't have Parkinson's.

"But eight months later he informed me that he had been diagnosed with
Parkinson's.

"So Joy wasn't correct for 11 out of 12, she was actually 12 out of 12 correct
at that time.

"That really impressed us and we had to dig further into this phenomenon."_

Reminds me of the story I heard about a doctor who was diagnosing an STD a lot
earlier than average. They put two other doctors in the room with him to try
to spot what he was seeing and identified the eye flutter as a new symptom, I
think for syphilis.

------
jarmitage
Reminds me of this anecdote from Fishing with John:

"I heard a story about this woman that was swimming in the ocean, and dolphins
started swimming with her, and the dolphins kept poking her in the chest above
her breast. She got scared and they took her out of the water, and she had a
big bruise right on the top of her breast. They took her to the doctor to
examine her, and they did a mammogram, and found that she had cancer right in
that spot."

– Jim Jarmusch, 'Fishing with John'

[https://youtu.be/uVa8rj1mm7A?t=912](https://youtu.be/uVa8rj1mm7A?t=912)

~~~
lost_my_pwd
Not sure if it is scientifically confirmed but it is believed that dolphins
can see inside a body to some extent with their sonar abilities.

~~~
jarmitage
Wow, link for that?

~~~
dewarrn1
I can't vouch for dolphin sonar resolving fine anatomical detail /in vivo/,
but dolphins can recognize visually obscured objects using the ability [0].

[0] [http://www.dolphin-
institute.org/our_research/dolphin_resear...](http://www.dolphin-
institute.org/our_research/dolphin_research/seeingthroughsound.htm)

------
klodolph
There are a couple people picking on this research in the thread. This is a
preliminary study, just a "bullshit test" to see if this woman is crazy or if
she's not. It's obvious that she's not crazy, because all she's doing is
sniffing t-shirts and she doesn't know who they belong to. The sample size is
large enough, we have a p-value of no more than p=0.0012, and that's under the
cynical assumption that she somehow knew that exactly seven of the twelve
samples would have Parkinson's... something that the scientists didn't know.

So we know that _something_ is going on here. The next steps are to control
potential confounding variables and to determine the sensitivity and
specificity of the test, if it's shown that she's not actually detecting some
confounding variable. This is where you go double-blind, you use larger sample
sizes, et cetera, now that you have money. You have money because the
preliminary research was promising.

And we're not just getting a good test out of this. If there's an actual
chemical that she's smelling, then there's some chemical process that's going
on in people with Parkinson's which isn't happening in people without
Parkinson's (or vice versa). Tracing these chemical pathways could give us
clues to the etiology of the disease, which would be a REALLY BIG DEAL. Or
maybe it's just a rabbit hole.

~~~
cbd1984
One of the great things about science is that we can determine whether a
phenomenon is likely real without having to have the slightest clue what the
mechanism might be. Evidence comes first, and this looks like solid evidence,
and mechanism can come later; the evidence alone proves the existence of
_something interesting_ , and that's what's worth a follow-up.

Hypothesis generation is important, because it helps us design the _next_
experiment, but _this_ experiment is _already_ very interesting.

~~~
nnethercote
> One of the great things about science is that we can determine whether a
> phenomenon is likely real without having to have the slightest clue what the
> mechanism might be.

You just have to ignore the people who shout "correlation is not causation" at
every opportunity, appropriate or not.

~~~
Pharaoh2
Because "correlation is not causation" is just plain wrong. What is should be
is "correlation does not imply causation". This is where science comes in. To
answer the question, is this correlation because of causation?

The statement is only important to people doing statistical analysis not
experimental science.

~~~
coldtea
> _correlation does not imply causation_

It sure does. It might not prove causation, or it might not necessitate
causation, but it very much implies it.

Somehow people forget that "imply" means: "indicate the truth or existence of
(something) by suggestion rather than explicit reference".

In this -- the dictionary and everyday sense -- correlation DOES imply
(suggest) causation. It just doesn't secure it.

~~~
graeme
That can't be right. There are so many spurious correlations that obviously
imply nothing.

There's got to be some other required factor before correlation can imply
causation. Like "if there's reason to believe something is relevant, and there
is correlation, then that implies causation. "

~~~
stephengillie
But a "reason to believe something is relevant" is a prejudged correlation.

------
Optimist45
I know the odor she is talking about. My husband was diagnosed in January. His
previous truck and his current vehicle have developed a very distinct odor. I
used to say old musty Portuguese man but I realize it is the smell she is
talking about. My husband has only used deodorant for 27+ years. This came
about because anti-perspirant made his entire armpit swell with bright red
welts. He also does not sweat much. It is a very sad disease, but will
continue to search for ways to make it easier.

------
tcdent
Interesting given the recent link between Parkinsons/Alzheimers and fungal
infections:
[https://news.ycombinator.com/item?id=10401344](https://news.ycombinator.com/item?id=10401344)

~~~
ksml
I would not call that a definitive "recent link"; as many in that thread
pointed out, that was not the greatest research and needs far more work to
confirm

~~~
tim333
Yeah, more research needed. I also came across another 2013 "Fungus may cause
symptoms of Parkinson's disease" article I found interesting.

They "found that a compound emitted by mold, called 1-octen-3-ol but more
commonly known as mushroom alcohol" "attacked two genes involved in the
creation of dopamine"

And speculate I think that could be related to the drop of in dopamine
production in Parkinsons.

It would be interesting to try some such "volatile organic compounds emitted
by fungi" with the lady who can smell Parkinson's to see it the smell was
similar.

[http://www.medicalnewstoday.com/articles/268848.php](http://www.medicalnewstoday.com/articles/268848.php)

Also a 1990 article suggesting it's "the fungus, called Nocardia asteroides."
I guess nothing much happening since 1990 suggests that didn't work out.

[http://articles.latimes.com/1990-05-17/news/mn-286_1_nocardi...](http://articles.latimes.com/1990-05-17/news/mn-286_1_nocardia-
infection)

------
andy_ppp
Some more truly fascinating Parkinson's news this week about nilotinib,
apparently seeming to cure Parkinson in small trials...
[http://www.independent.co.uk/life-style/health-and-
families/...](http://www.independent.co.uk/life-style/health-and-
families/health-news/parkinsons-patients-given-new-lease-of-life-after-
receiving-cancer-drug-in-trial-a6699031.html)

~~~
tim333
Thanks for the link. There is another article in the New Scientist with more
information [https://www.newscientist.com/article/dn28357-people-with-
par...](https://www.newscientist.com/article/dn28357-people-with-parkinsons-
walk-again-after-promising-drug-trial)

I'm on the look out for stuff for my dad who seems to have it. The data in the
New Scientist article looks promising - all 12 of the patients started to
improve, some dramatically and as to side effects the "team saw no unwanted
effects".

------
conductor
Can anybody tell us what is the current state of the art in "electronic nose"
sensors technology? Could they potentially be used to identify this smell?

~~~
TeMPOraL
We're pretty good at detecting low concentrations of chemicals in the air _if
we know exactly which ones to detect_. This case suggests there might be some
previously unnoticed substances in the air that are indicative of one's
Parkinson. If so, we'll probably quickly build dedicated sensors.

The thing that makes me wonder though - what's the state of broad-range
chemical sensing? Could a chemical like this be found before if we kept taking
broad "smell" samples of everyone and cross-correlating them?

------
seccess
My grandpa died of parkinson's, its a really slow and heartbreaking disorder.
I think early diagnosis would be wonderful. It runs in the family, and his two
older brothers and father had it, so he lived a very preventative lifestyle -
especially with respect to daily exercise. I think it paid off, he lived to 85
while both his brothers died 20 years younger.

------
tomcam
Galen relied on sense of smell for diagnosing illnesses. Aristotle wrote about
it. Until the late 20th century doctors often used smell for diagnostics.

------
firebones
It would seem there are some major confounding factors here not detailed in
the article.

1) The population doesn't reflect a realistic test--if the overall incidence
is 0.3%, but the sample size had 50% (or more given her adamant hit), then we
need to know whether she was expecting more. 2) More importantly, the
incidence in men is 1.49x that of women [1], and age also plays a factor. So
given that the sample is already skewed towards a higher incidence of
positives, the gender differences might be factored into her senses--
especially since it was her husband who was her training set. With n=12, it
would be very easy for the probabilities/priors to be much different than
truly random. (E.g., the learning function of her nose might be "men + people
over 65" which happened to match up with the test and control group quite
well.") Or it could tune into medication used to treat the disease.

Great if true, but I am skeptical.

[1]
[http://jnnp.bmj.com/content/75/4/637.full](http://jnnp.bmj.com/content/75/4/637.full)

~~~
KingMob
If you look at the Bayesian analyses and the frequentist analyses assuming she
knew how many AD shirts there would be, you'd see that point 1 doesn't matter.
We can statistically test this without the need to make her sniff 1000's of
shirts.

Point 2 is interesting though, and the first thoughtful criticism I've seen in
the thread. What if she's both a bit lucky, and also picking up on some
correlated marker like age/gender?

------
nyc111
The question they did not ask what makes the body smell. When we eat garlic we
smell like garlic. So the smell must be related to how the food is digested.
The researchers should look at the gut flora, in other words they should do a
study similar to this
[https://news.ycombinator.com/item?id=10439129](https://news.ycombinator.com/item?id=10439129)
All disease start in the gut.

------
JulianMorrison
Seems like they are going the long way about it to determine a molecule for a
test.

Why not just train a dog to smell it?

~~~
jmiwhite
Smell what?

It seems that _how_ this works is still unclear, if it works at all. Once
validated, it seems plausible that a device/trained animal could replicate the
results, assuming its not like this guy:
[https://en.wikipedia.org/wiki/James_Harrison_(blood_donor)](https://en.wikipedia.org/wiki/James_Harrison_\(blood_donor\))

------
cafebeen
Looking forward to hearing more--reminds me of work done to detect cancer by
scent with help from dogs:

[https://en.wikipedia.org/wiki/Canine_cancer_detection](https://en.wikipedia.org/wiki/Canine_cancer_detection)

------
Mz
This also reminds me of the breathe test being developed to check ammonia
levels for certain kinds of patients:

[https://news.ycombinator.com/item?id=10402816](https://news.ycombinator.com/item?id=10402816)

------
codeonfire
I'm too lazy to do the math, but I'm just going to say a test like this needs
more than a sample size of 12 to show significance for detecting something
that happens 1 in 500. The woman also was predisposed to thinking that at
least some of the 12 had Parkinson's and the sample selection ensured that at
least half did have Parkinson's. An actual test would need to allow any
possible sample including those that had zero Parkinson's patients.

~~~
klodolph
You're right... you are too lazy.

Traditional null hypothesis would be something like "she guesses right 50% of
the time", which gives a likelihood of 1/16384 that she would get the correct
answer. Let's be cynical, and suppose that she knew or guessed that there were
5-7 patients with Parkinson's, the likelihood is now 1/2538, still pretty low.
Even if she knew there were exactly 7 patients with Parkinson's (quite a
cynical null hypothesis!) the likelihood is only 1/792\. Hey, that's a p-value
of 0.0012!

Yes, p-values suck. But, the significance is absolutely there, but we would
want to follow this research up with a larger sample size and control more of
the variables.

~~~
Gravityloss
Let's apply Bayesian reasoning. :P

P(skill): Let's choose a prior that someone can smell parkinson's as one in a
million, or 10^-6. (Not very well argued, I admit.)

P(data): This exact data's random occurrence probability is 1/2538.

P(data|skill): The probability of the result, taking account that she has the
skill, is 1 (this assumes she never errs).

So we get

    
    
        P(skill|data) = P(data|skill) x P(skill) / P(data)
    
        P(skill) = 1 x 10^-6 / (1/2538) = 0.002538
    

Or 0.25 percent probability, based on this test, that she has the skill. Which
is low.

Intuitively, I would have expected the calculation to yield a much higher
number. The prior was very low though.

So I think the grandparent post has some merit. It can be argued that the
claim is so extraordinary (the prior) that even twelve "coin tosses" guessed
right in a row is more likely.

~~~
biomcgary
How many people claim they can smell Parkinson's? How many otherwise truthful,
sane people have falsely made this claim? Perhaps a better approach to a prior
would take into consideration that she claims that she can smell Parkinson's
and her reputation as a truthful, sane person. My prior wouldn't be less that
0.1.

~~~
codeonfire
So, with no scientific basis at all you believe there is a 10% chance that
people can detect disease by smell, something that has AFAIK never been proven
for any disease? We don't go to the doctor and have him or her smell our
armpits. Do you use a psychic? What we have here is an organization that is
basing their research funding on math tricks that I, ten years out of
undergrad, maybe didn't remember exactly as it was characterized but was able
to see through.

~~~
klodolph
There are so many things wrong in this comment it's hard to figure out where
to begin.

"We don't go to the doctor and have him or her smell our armpits" is an
argument to authority. Just because a doctor doesn't use test X does not mean
that test X is not useful. Every single diagnosis test we use today was, at
some point in the past, unknown and unused by doctors. It is scientific
research which gave us those tests. And, because you seem to be uninformed
about the subject, I'd like to tell you that there are a number of things that
a doctor will smell when they diagnose you. Famously, you can diagnose
phenylketonuria by smell, and you can also diagnose diabetes by smell.

This comment also seems to reflect a fundamental misunderstanding of the
scientific process. The whole point of scientific research--which requires
funding, usually--is to figure out if a hypothesis is true or false. If you
already know whether your hypothesis is true or false, you're not doing
research, you're replicating results.

When you do preliminary research, it's because you don't have very good
information about some particular subject. You're complaining about the shaky
ground that they base their research funding on--but these scientists did the
right thing. Because the hypothesis seemed improbable, they conducted a dirt
cheap experiment. It's an experiment that you could have conducted yourself
for $20.

~~~
codeonfire
> If you already know whether your hypothesis is true or false, you're not
> doing research

That's exactly what this is. People believe the claim 100% so we do a simple
coin flip, and, yes, there it is. It's confirmed! No extraordinary evidence
required for this extraordinary claim. Let the research money flow and the BBC
reporting commence. If it were my money I would have another lab repeat the
experiment.

------
2skep
I bet they didn't randomise for brand of deodorant and diet which makes this
research almost meaningless.

~~~
knodi123
it was a sample of 12 people, so it's already meaningless. this "research" is
the justification for a study, not a study in and of itself.

~~~
sliverstorm
How is it simultaneously meaningless and also a justification for further
study?

~~~
opnitro
Meaningless to draw large scale conclusions on. It's a "This is something we
should look more closely at" not a "Send this person around the country STAT"

------
consta
Impressive but I don't see the point of diagnosing Parkinsons in early stages
when there is no cure available.

~~~
ajkjk
Fortunately, everybody else does. Why would we not want to be able to discern
life-threatening information sooner?

Not to mention the value in correlating another physiological change with the
disease. Maybe research into how this works can get us closer to a cure.

~~~
Alex3917
> Why would we not want to be able to discern life-threatening information
> sooner?

Because there's a good chance you'll receive a treatment that will cause you
to die sooner than had you not known about the disease for another decade.
C.f. why they pushed back the recommended age for mammograms this week.

~~~
ajkjk
That sounds like a problem with the treatment, not a reason to remain ignorant
about your own health for longer.

