
Dogs demonstrate the existence of an epileptic seizure odour in humans - howard941
https://www.nature.com/articles/s41598-019-40721-4
======
jackschultz
Super interesting.

I also just want to note to people that seizures aren't always the kind that
they're portrayed, with the person falling to the ground and shaking.

Couple years ago I had these events start which turned out to be partial
temporal lobe seizures. I would get a big flash of deja vu, my right arm would
tingle starting at the shoulder and creep down to my fingers for about a
second, and then I'd get hit with a tiny thump in my head where for the next
few minutes I couldn't comprehend. I could still think, and I was able to tell
people I was talking to to hold on, and give me a little time before we could
start talking again. I had one while reading for example and the words got
completely meshed together, where the characters were combined in different
orders and didn't look understandable at all. I was wondering why the hell I
couldn't read, and eventually the words started coming back together.

The reason I'm saying this is that it took more a while to realize these are
considered seizures. I didn't know what was going on and didn't think it was
anything much until they started coming one a day and that thump getting a
little bigger each time.

This kind of seizure was listed in the paper as one of the test subjects.
Someone I know was the one to tell me that those events might be a seizure,
and I don't know how much longer it'd have been for me to come to that
realization on my own. So maybe me saying this can help someone else. That, or
get a dog that can smell seizures like in the paper!

~~~
jshowa3
Please. If you're having medical problems, consult a doctor. Don't let hacker
news speculate a diagnosis like in this post. And don't get a dog to detect
your seizures.

~~~
dev_tty01
I have no doubt that you meant well and have good intentions. Nonetheless,
your comment is insulting to its audience. You are assuming people are too
stupid to take care of themselves and need this advice. Please reconsider
before making obvious suggestions that make assumptions about the targets
intellect and ability to make their own decisions.

Open discussions of health issues and understanding that one is not alone can
be both encouraging and directly helpful in pursuing a better diagnostic
outcome.

~~~
basementcat
+1 on consulting a medical professional.

That being said, I'm sure there are online forums for doctors out there like
HN or StackExchange or Reddit with their own hilarious troll culture.

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codeulike
Among people with epilepsy or who have children with epilepsy, its pretty
common to hear discussion about 'seizure dogs'. These are either pets or
specifically trained dogs that can predict when a seizure is going to happen,
sometimes up to an hour before. They are somewhat rare but certainly a known
phenomenon.

Apparently the training is a bit hit and miss, some dogs can do it and some
can't. Training a dog to react to a seizure that is actually happening right
now is quite a lot easier, and still very useful (e.g. train it to run to
parents room, barking).

edit: also, one hears of scams where people claim to be able to provide
seizure dogs but dont, so bear that in mind.

~~~
Swizec
How do you even begin to reinforcement train a behavior you don’t understand
the trigger for? That sounds fascinating!

I can understand how to train a dog if I know “Ok this person is having a
seizure in X minutes, time to cue the dog”

But when you don’t know? Would you need an existing trained dog to bootstrap
with? Who trained the first one?

~~~
cgriswald
There is a scent, I believe it is a hormone but I don’t think it is what the
body actually produces. If a dog reacts to it they can try to train it. If it
doesn’t, they train the dog for something else or find it a good home. They
also have people fake seizures. You can probably find some YouTube videos of
it.

We have a dog that could do it. She could warn us about my partner’s seizures
and fainting a few minutes before it happened. She could fetch help and apply
pressure to the abdomen. (I say could because my partner had surgery a year
ago and hasn’t had any seizures or fainting since then.)

I definitely noticed a change in my partner before seizures (but not
fainting). The dog alerted on me once during a moment of high anxiety. I
wouldn’t begin to argue WHAT the dog is actually reacting to, but the training
methods people are using seem to work.

~~~
hinkley
I wonder if the fake seizures confuse the dogs about what signs to look for...
Might be a quantity over quality problem though (how would you train enough
dogs without faking it?)

~~~
cgriswald
I’m not an expert on this so I’m just guessing but I think the fake seizures
are more for training what to do during the seizure rather than the detection
part.

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JoshTko
The fact that an odor precedes a seizure is interesting. Implies that there is
some chemical buildup of some sort which also might suggest new ways of
detection, prevention or treatment.

~~~
harveywi
It is a strange coincidence however that the seizure chemical is the same
chemical that causes a dog to bark.

~~~
b_tterc_p
It’s probably just that the dogs can detect a problem and are barking out of
empathetic concern or fear (if not trained)

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thorgutierrez
I'm curious if anybody knows if there are good reasons why we can't or why
it's hard to invent machines that could smell / detect particles in the air as
well as dogs?

~~~
jerf
We have a long way to go before we are even remotely as good at nanotechnology
as biology is.

I'd give decent odds we'll sooner grow a dog nose in isolation and interpret
the neural signals directly than build a machine as good as a dog's nose. (And
I'm not saying that's easy, either.)

~~~
chucksmash
The mental image of walking through, say, a security checkpoint that contains
an artificially grown dog nose that sniffs you as you go by seems as good a
writing prompt for dystopic fiction as you could ask for.

~~~
kevinmchugh
There was a British company which attempted to develop drug and bomb-detecting
tools powered by bees. They would condition bees to associate the smell of a
particular drug or explosive with receiving a morsel of food. Then load the
bees into cartridges, put a dozen or so of the cartridges in a wand format and
hand them to security staff at airports.

It doesn't appear to have gotten off the ground, I can't even find the name of
the company any more.

------
abhinai
Several such stories imply that if we are ever able to build machines that can
_smell_ things, we might open up an entirely new world of diagnostic tools for
medical sciences. Though I am not sure how well we understand how _smell_
works and I recently read somewhere that human smell system might use quantum
tunneling so I would say such a system might be decades away if not more.

~~~
slacka
I am constantly in awe of my dog's snout. Evolution has produce a tool that
detect odors in parts per trillion! His favorite game is "hunting humans" as I
call it. I can go over a mile in the woods behind my house. And have no doubt
my dog will find me minutes after my family unleaches him.

When another dog was sick with cancer, he showed interested in that area. I
have no doubt there is untapped medical potential in this area.

~~~
lostlogin
A relative has one that can find tennis balls. It doesn’t matter how long they
have been lost in a shrub or overgrown corner, she suddenly diverts, smashes
in and comes out with her trophy. She doesn’t even have to be particularly
close to detect them.

------
WhompingWindows
A similar story is Oscar the Cat, from an advanced dementia ward named Steere
House in Providence, RI. Amazingly, the cat was able to smell death, and would
hop up onto the deathbed and wait as the person passed. I knew the cat
personally, it was not friendly, and many family members attempted to bar it
from entering a room, and Oscar would scratch insistently to get into said
room.

While one physician was monitoring the cat's predictive capacity, he noted a
streak of ~20 successful predictions of death by the cat.

[https://en.wikipedia.org/wiki/Oscar_(therapy_cat)](https://en.wikipedia.org/wiki/Oscar_\(therapy_cat\))

~~~
Havoc
Ironic that in an earlier time the cat would probably have been killed for
"bringing death"

------
nateberkopec
As a search and rescue volunteer, I have had a number of fascinating
experiences with trained scent dogs. I thought scent dogs only really worked
in the movies, but watching them work to find humans lost in the woods was an
eye-opening experience.

I watched a dog in training follow a 1km scent trail that was several hours
old. This dog was not even fully trained for the activity and followed every
footstep to the subject.

They really do navigate with their nose, as well. I was the subject for
another exercise, and I watched a dog look almost straight at me, not see me,
then pick up my scent and follow their nose straight to me.

~~~
andyidsinga
that's really cool. We do "nose work" with our dogs just as a game for them.
Its super fun to watch them find treats and toys we hide for them.

What I was most surprised about when we started is how the game sort of wears
them out almost like a good run at the park. (we have 2 aussies and 2 silken
wind hounds)

------
chadlavi
Parkinson's, too: [https://www.bbc.com/news/uk-
scotland-42252411](https://www.bbc.com/news/uk-scotland-42252411)

------
Raphmedia
There's quite a few diseases that can be smelled.

I think it's pretty interesting and often wonders if that's the reason some
people have some kind of "sixth sense" when it comes to diseases.

[https://academic.oup.com/jb/article/150/3/257/867730](https://academic.oup.com/jb/article/150/3/257/867730)

~~~
clairity
yes, i think our sense of smell is pretty good but we tend to ignore the
contribution of smell into our conscious thoughts. sometimes when my dog
sniffs at something in the house, i’ll go sniff it too, and will find
something weird there as well. not only does my dog have a better sense of
smell, she’s constantly consciously processing that data too, and alerting me
about it. it’s very nice. =)

~~~
Raphmedia
I'm on hormone therapy and my sense of smell drastically improved. That means
that a lot of things are new to me and immediately pop into my conscious mind
instead of getting filed up in the back of my mind.

Probably look like your dogs at times. Often I would go sniffing around the
home or the office and find things such as forgotten food scraps, electronics
heating up, etc. The most useful so far has been pinpointing mold issues.

I've noticed how some people smell drastically different and often wonder
about their health and diet.

~~~
sneakernets
Oh my god, this happened to me too. I smell my old monitor now and it's pretty
bad. I once liked the "smell" of old electronics powered up but now it's
unbearable. My 60s vintage Zenith radio is one of the worst offenders.

------
cdransf
Interesting stuff. My grandmother has had seizures for decades following a
head injury in a softball game. Her and my grandfather at one point rescued a
Great Dane mix and over time he would begin to lean on her before a seizure
would come on and would then stay by her until she came out of it.

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luckydata
Considering everything happening in our bodies has to have a chemical
component, is it really that surprising?

Sometimes medicine strikes me as "we discovered this completely obvious thing
we could have gotten to from first principles but decided to ignore since our
detection methods were not good enough and we were not paying attention to the
signs".

Speaking like a complete outsider, please educate me further.

~~~
saagarjha
Not every chemical component has to have outward signs, though?

~~~
thfuran
Yeah, the brain is pretty well isolated so I don't think it's totally obvious
that this should be the case.

~~~
oliveshell
Exactly. Seizures represent massively synchronized electrical activity, so
it’s a bit surprising that they’re associated with chemical changes big enough
to be detected outside the body.

We do know that this electrical activity is controlled via ion channels and
other chemical mechanisms. So a neuroscientist could well have guessed that
this might be the case.

But we have all _sorts_ of hypotheses about what “really happens” in the
brain. It’s such a fantastically complex system, though, that they’re not too
useful for extrapolation in the absence of data.

------
anodyne33
Weirdly enough when I was epileptic ('12-'17, couple of brain surgeries fixed
that up) the auras I would experience were an occasional olfactory
hallucination. I can't imagine there's any physiological connection outside of
the brain but it's still a weird coincidence to read about "smelling" a
seizure.

~~~
SippinLean
Yeah I always have a metallic taste in my mouth before a seizure. I wonder if
it's related.

~~~
anodyne33
From what I've learned auras can manifest in all kids of manners and that's
one of the prevalent ones. I have a few friends with migraines and that's
common for them as well. There's a really, really strong correlation between
the mechanisms at work in Epilepsy and migraines.

------
karmelapple
I have anecdotal first-hand experience with a dog who smelled cancer - or at
least something very wrong with their health - in a loved one, and there seems
to be other anecdotes, too [1].

My family member already knew she had ovarian cancer, but when we went to
visit a friend's house with a dog she had never met, the dog acted in ways
that the owners were amazed to see. The dog usually was a ball of energy,
running all over the place, but when my family member with cancer sat down,
the dog was extremely gentle and wouldn't leave her side. The owners said this
was not at all typical behavior of their dog.

[1] [https://www.health.com/ovarian-cancer/dog-detects-owners-
can...](https://www.health.com/ovarian-cancer/dog-detects-owners-cancer-
before-doctors)

------
chronogram
Thanks for this link. Are you related to this? I’m interested in this part
_“Further studies will aim to look at potential applications in terms of
anticipation of seizures.”_ And if you’re into this field, could you let me
know how I can stay up to date with those further studies?

~~~
howard941
You're welcome.

> Are you related to this?

I'm not. You may be able to contact Amélie Catala, the first listed
researcher, by way of the link supplied in the abstract.

------
pesterazor
I find this piece of evidence fascinating. I guess how many other conditions
have a specific odour (or are associated with odour changes) and if there will
ever be an artificial way to promptly recognize them. I apologize for my
grammar, English is not my native language.

~~~
stallmanite
Whoops now I feel dumb, there was one small issue. Just swap “wonder” for
“guess” and you’re good.

------
kyleblarson
Dogs' connections to their humans are amazing. While I work, my Australian
Shepherd senses when I am stressed (even if I am not outwardly displaying it),
comes over to me and puts his paw on my leg.

~~~
andyidsinga
i have two Aussies - they're great and super smart.

after reading the book "chaser" \- I trained one of them to distinguish
several toys by name similar to what he had done in the book. it was a lot of
fun and now he's always bringing me toys to play with. Interestingly he brings
them at very specific times of the day when I'm most likely to play with him:
morning while making coffee, and evening while cleaning up the kitchen.

~~~
kyleblarson
I'll check out that book. Ours knows a couple of his toys by name but it would
be fun to teach him more.

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a-dub
"As we focused on ictal odour and not on pre-ictal, we did not make
assumptions on seizure-alerting abilities of dogs, or on the timing of such
anticipation, in this study."

Would be far more interesting if they could get it to work before the
seizures. It's not terribly surprising to me that they can detect post-seizure
odor, it's a pretty violent physiological event where I'm sure all sorts of
things get secreted. It would be remarkable if they could pick up on a pre-
seizure odor like how is described in the introduction....

------
progfix
I only read the Abstract, but it might also be an unusual change in odour that
the dogs detect instead of a specific "seizure-odour".

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snissn
Is anyone familiar with any "electronic nose" systems and what the cutting
edge of them is now? I've worked on some systems vaguely similar to theranos a
decade ago around analyzing blood samples and contemplate those in airport
bomb detectors. Any companies working on productizing these type of
technologies?

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amelius
After quickly scanning, it seems that they tested against "calm activity" and
"physical activity". But not against "feeling unwell". This seems a bit
strange because it would mean that the marker could still be very unspecific
(and may perhaps have little to do with seizures).

------
singingfish
Interesting. Many years ago I was on a bus. Suddenly I smelled a very strong
distinctive unusual smell. Next thing the guy in front of me was on the floor
having a full grand-mal. From this experience, I had assumed that seizure
odour was a known thing. Apparently my assumption was wrong.

------
ngngngng
How does someone with internet access learn how to train dogs for things like
this? All I can find on youtube is how to train my dogs to do silly tricks.
I'd like to know how seeing eye dogs, therapy dogs, police dogs, and other
types of professional dogs are trained.

------
JJMcJ
Old time docs would sometimes sniff their patients (in private places) to get
clues for a diagnosis.

~~~
jcoffland
And taste their pee.

------
hinkley
Is there a word for when a breakthrough is made and people aren't surprised
because they thought we knew this decades ago? I bet the Germans have one...

I am certain I'd heard of service animals that could tell a seizure was about
to happen.

------
danschumann
This is the most advanced domestication function yet! Just think when humans
utilized dogs for just barking at predators who came near.. and now they can
detect tiny particles in the air for us.

------
tantalor
"we hypothesized that there may be a seizure-specific olfactory component that
would be common to different individuals and types of seizures"

Vague & untestable. This is not a scientific hypothesis because it's not
falsifiable.

It's missing a suggested explanation of the phenomenon. What happens between
the seizure and the smell? Magic? Fairies? How could a seizure cause an odor?

The study fails to establish that the dogs are relying exclusively on odor.
For all we know there could something else happening. For example, we know
dogs can sense magnetic fields. What if the seizure patient releases some kind
of ferromagnetic material which the dogs can detect magnetically?

~~~
Sniffnoy
You seem to be confusing "this is not a sufficient test" with "this is not
testable". And not knowing the mechanism does not make something
unfalsifiable. (I mean, _most_ phenomena are discovered before any mechanism!)

