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Dogs demonstrate the existence of an epileptic seizure odour in humans
- chadlavi 8y agoParkinson's, too: https://www.bbc.com/news/uk-scotland-42252411 https://www.bbc.com/news/uk-scotland-42252411
- codeulike 8y agoAmong 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 8y agoHow 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?
- hanoz 8y agoPresumably this effect was first noticed without any training, when dogs who'd witnessed their owners having seizures made the connection and started to get agitated when another was imminent.
- guitarbill 8y ago> More specifically, the training for SAD required three main steps. First a positive association is created between the scent of a seizure and treats in order to induce a conditioned emotional response. The paper goes into a bit of detail on training, but it's a fair and interesting point: How do they get the seizure scent? I guess you could maybe take a sample just after a seizure, or a second person could do it if they were present and prepared to take it.
- turkeysandwich 8y agoThey took samples after/during seizures.
- dymk 8y agoSamples of what, though? Sweat? Clothing?
- turkeysandwich 8y agoSweat.
- codeulike 8y agoI imagine you train them to react to seizures, and they figure the predictive bit out themselves, if they are able to.
- uf 8y agoStimulus generalization comes to mind. IIRC Pavlows dogs at some point reacted not just to the food, but even earlier on him entering the room. I doubt that they train dogs like "Steve's having a seizure. Good! Get that dog here." I imagine that you do a preliminary training with faked seizures to get responses right and then hope (meaning: Train under real conditions) that the dog will react on a real seizure as well.
- cgriswald 8y agoThere 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 8y agoI 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 8y agoI’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.
- turkeysandwich 8y agoYeah... that website is a scam. Seizure alert dogs have not been established to be effective yet. A claim of "100% reliable" is guaranteed to be woo.
- codeulike 8y agoI have heard of scams in this area so you might be right. I removed the link. I believe that such dogs do exist, but they are rare.
- vectorEQ 8y agoi believe dogs can sense a lot on their owners. that doesn't mean it's by smell though. people just pin it on smell often as dogs nose is very good. that doesn't mean it's the only sensor they have.
- harveywi 8y agoExactly. For example, the person could be emitting an extremely high-pitched tone before the seizure that is inaudible to the Human ear yet can be heard by the dog. Sort of like a camera flashbulb.
- turkeysandwich 8y agoPossibly, but I feel behavior is probably the biggest tell for dogs. Their owner starts acting funny right before a seizure comes on.
- thinkharder 8y agoI have a tendency to let frustration build up until I lose my temper. The issue is that I don't realize I'm doing it until I'm ready to explode. My last dog was so sensitive to that, that she could tell when I was starting to get angry before I would realize it. I would be sitting at my computer, struggling with something, and I'd feel her poke me in the leg with her nose, then I knew it was time to take a break. I think she could hear that i was typing 'harder' when I got angry, but it could have been any one of a lot of tiny signals. Point is, she was consistently aware of me getting angry before I was. I miss that dog...
- chx 8y ago> Training a dog to react to a seizure that is actually happening right now is quite a lot easier, and still very useful Aye especially where the dog puts their body between the seizing patient and the floor preventing serious head injuries. You can see the training here https://youtu.be/ZskqSLnMDRQ https://youtu.be/ZskqSLnMDRQ Also, postictal sucks. Really, really, really sucks. It's one of those things words can't do it justice. Wikipedia says "it is characterized by drowsiness, confusion, nausea, hypertension, headache or migraine, and other disorienting symptoms... often accompanied by amnesia or other memory defects". Having a trusted friend (like your dog) next to you during is very, very helpful.
- chronogram 8y agoThanks 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 8y agoYou'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.
- thorgutierrez 8y agoI'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?
- echelon 8y agoIt's not that we can't. We're just now beginning to characterize this in dogs now. Next we need to identify the chemical signal and develop hardware to pick up that signal.
- pbhjpbhj 8y agoIf it's the strength of a particular chemical signal -- like dogs can normally smell it, but it's suddenly stronger -- then that seems like it's going to make false detections very difficult. Training a machine to have an innate sense of how smell works under changing environmental conditions seems like it's going to be hard.
- jerf 8y agoWe 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 8y agoThe 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 8y agoThere 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.
- JoshTko 8y agoThe 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 8y agoIt is a strange coincidence however that the seizure chemical is the same chemical that causes a dog to bark.
- heavymark 8y agoWell it's odor they can detect and distinguish, and then can be trained to either bark and or take other actions.
- b_tterc_p 8y agoIt’s probably just that the dogs can detect a problem and are barking out of empathetic concern or fear (if not trained)
- iceninenines 8y agoDogs, being social pack animals who co-evolved with people, are very adept at reading anthro-socio-emotional communication because tens of thousands of years of survival depended on and reinforced it. It's also likely that they're not consciously aware of what's wrong, but sense something is wrong because of an association formed by the distinct odor preceding a seizure.
- bradjohnson 8y agoDogs don't need a chemical to make them bark.
- turkeysandwich 8y agoThis study doesn't establish that an odor precedes a seizure. They took the samples from someone who was in the middle of a seizure or shortly afterwards.
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- snissn 8y agoIs 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?
- Raphmedia 8y agoThere'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
- csomar 8y agoOr, maybe, humans have the olfactory capcities but these sensations are not transfered to the consious.
- Raphmedia 8y agoThat's what I was trying to say. The sense of smells really affects you in subtle ways. A positive smell can calm you and a negative one bring anxiety. I wonders if some people are able to intuitively "feel" diseases that way.
- clairity 8y agoyes, 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 8y agoI'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.
- abhinai 8y agoSeveral 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 8y agoI 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 8y agoA 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.
- svara 8y agoThe sense of smell is a sense for the identity of (typically small) chemical compounds. So there absolutely are machines that can "smell" things. E.g., mass spectrometers, or in a broader sense any technique that can detect specific molecules.
- AnIdiotOnTheNet 8y agoBut detecting compounds is only a small part of the equation. A significant portion of a dog's brain is engaged to analyze scent data. It's like how we've had CCDs for a really long time but being able to detect objects in the image data they capture is relatively recent.
- anodyne33 8y agoWeirdly 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.
- harveywi 8y agoThis is fascinating. If you do not mind me asking, what was the smell that you experienced?
- anodyne33 8y agoI don't remember anything specifically but I do seem to remember that it wasn't any one particular thing. If it was immediately pre-ictal I wouldn't have been likely to remember at all. I had two generalized seizures before I made it to my neuro and started Depakote (bad stuff) and then just had complex partial seizures. I'd just zone out for a half a minute or so with no memory of that time. There were times that I was walking down the street with coworkers, had a seizure and dropped my lunch and just kept walking along the whole time.
- SippinLean 8y agoYeah I always have a metallic taste in my mouth before a seizure. I wonder if it's related.
- anodyne33 8y agoFrom 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.
- luckydata 8y agoto me that's a pretty good indication that there must be hormonal fluctuations before a seizure. Sorry to hear you're suffering from the condition, it must not be pleasant.
- JJMcJ 8y agoOld time docs would sometimes sniff their patients (in private places) to get clues for a diagnosis.
- jcoffland 8y agoAnd taste their pee.
- jackschultz 8y agoSuper 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!
- milankragujevic 8y agoOh wow, I get that. You scared me. I need to go to a neurologist quickly then, I guess.
- tasseff 8y agoYour symptoms sound like those of a transient ischemic attack, which commonly preempt a stroke. You should take these very seriously.
- latortuga 8y agoThe symptoms described are a very typical presentation of partial seizures as well. Deja vu is a common symptom, but it heavily depends on which part of the brain the seizure occurs in.
- cdransf 8y agoInteresting 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.
- pesterazor 8y agoI 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 8y agoOff-topic but your post is grammatically perfect as far as I can tell. No need to apologize.
- stallmanite 8y agoWhoops now I feel dumb, there was one small issue. Just swap “wonder” for “guess” and you’re good.
- progfix 8y agoI only read the Abstract, but it might also be an unusual change in odour that the dogs detect instead of a specific "seizure-odour".
- amelius 8y agoAfter 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).
- nateberkopec 8y agoAs 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 8y agothat'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)
- luckydata 8y agoConsidering 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 8y agoNot every chemical component has to have outward signs, though?
- thfuran 8y agoYeah, the brain is pretty well isolated so I don't think it's totally obvious that this should be the case.
- oliveshell 8y agoExactly. 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.
- luckydata 8y agoI find it extremely hard to believe that something like a seizure wouldn't create any changes in the hormones of a person that's about to have one. Apparently it's not that much of a foregone conclusion as I see others have replied saying for them it's just an electrical reaction in the brain (which I can't agree with in principle, that's not how the brain works, most brain activity is chemically mediated).
- kyleblarson 8y agoDogs' 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 8y agoi 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 8y agoI'll check out that book. Ours knows a couple of his toys by name but it would be fun to teach him more.
- ngngngng 8y agoHow 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.
- hinkley 8y agoIs 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.
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- karmelapple 8y agoI 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-cancer-before-doctors https://www.health.com/ovarian-cancer/dog-detects-owners-can...
- tantalor 8y ago"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?
- phreeza 8y agoIt is falsifiable. E.g. you could sever dogs olfactory nerves and repeat the experiment.
- Sniffnoy 8y agoYou 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!)
- WhompingWindows 8y agoA 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 8y agoIronic that in an earlier time the cat would probably have been killed for "bringing death"
- danschumann 8y agoThis 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.
- a-dub 8y ago"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....
- singingfish 8y agoInteresting. 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.
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