Dogs demonstrate the existence of an epileptic seizure odour in humans

I was diagnosed with temporal lobe seizures when I was a teenager. What you described is very similar to my experience ... with the aura as you sense the seizure coming on, followed by a period of disorientation and short-term memory loss. As I got older, I learned to sense them coming on, and at times felt as-if I could almost fight them back and prevent them from occurring in some instances, but maybe that was just me pretending I had more control over them than I actually did.

When they did occur, I'd find myself "detached" from whatever environment I'd been in, and then struggling to re-engage with those around me. Most-strange was that I found in some cases I'd not only forgotten memories but also feelings I'd had for others. Try re-learning that you love your girlfriend after a seizure.

I went through numerous EEGs, sleep-deprevation EEGs, MRIs and a slew of other tests and was able to regulate the seizures using medication. But it did impact my life. It prevented me from pursuing a career that required a clean bill of health despite having my condition under control with medication.

Later in life, when I was planning to have children, I worked with my doctor to reduce then eliminate my medication. Though there was no indication that it would cause a problem, it wasn't something I wanted to risk. I've been off of the medication for about 10 years and seizure-free for over 20 years - long enough where I've stopped keeping track.

I have no explanation for why I no longer have these seizures but I feel fortunate that it's something seemingly very much in my past.

Something that you should know is that simple and complex partial seizures (also sometimes called focal seizures, or less formally "auras") like this can and do generalize into tonic-clonic (formerly: grand mal) seizures. You should definitely see a neurologist about this, ESPECIALLY if it's new and the frequency is increasing.

My wife started getting partial seizures much like during her second pregnancy and they culminated in a generalized tonic-clonic seizure. Her OB mis-diagnosed them as vasovagal syncopy, which is a very common phenomenon during pregnancy.

Based on getting a diagnosis it sounds like you've seen someone about this. Please, anyone out there who has similar symptoms, get it checked by a neurologist!

I have partial temporal lobe seizures as well. My primary symptom, which is visible from the outside that is, is that I lose the ability to use language. If I try talking, it just becomes a mangled mess of words in English and Swedish. I also can not understand what other people say.

It's a very peculiar feeling to be conscious and fully aware of what is happening, but still completely lose such a fundamental part of my brain functions.

Former Epileptic (brain surgeries in '17) here. After I had two generalized seizures in my sleep (good thing I was living with someone at the time or I'd have never known) I met my local neurologist and was put on Depakote.

From there out I had complex partial seizures and would simply zone out for a minute, give or take. If I was around my girlfriend or coworkers I told them to let me know otherwise I'd have no idea that I'd had a seizure aside from occasionally peeing myself a bit. Incontinence regularly correlates with seizures.

I mentioned this elsewhere but there was one specific time that I was walking back down the street with coworkers, dropped my sandwich and kept walking. One of my buddies caught up to me, handed me my sandwich and that 30 sec. or so was just gone even though I kept walking down the sidewalk.

I was right temporal focal and have the pathology report on the hunks my surgeon cut out on my wall. The photo of my post op MRI with noticeably less brain on one side than the other is a great conversation starter.

Yeah. I had a similar experience. I only learned the small, random "blips" I was having was epilepsy after one finally evolved into a full-on seizure and I woke up to a bunch of paramedics standing over me. Unfortunately I denied it and refused to take medicine until I had another grand mal seizure and was injured really badly.

My brain started malfunctioning about 6 months before that. I would get this sensation where I couldn't understand or produce language for 5-30 seconds at a time. It seemed innocuous enough, and people actually told me it was normal, that they forgot words all the time. I don't have any physical or emotional manifestations during those auras (small, partial seizures)

I wish I had gone to a doctor because they would have probably run an EEG and put me on epilepsy medication earlier. Medication can actually slow or halt the development of epilepsy. Unfortunately, these small seizures reinforce themselves over time (epileptogenesis) and your brain essentially learns to have seizures.

I had a sort of similar "weird" seizure as a one-off: https://dmd.3e.org/2005/11/aphasia-and-back-sunday-20-novemb...

Oh wow, I get that. You scared me. I need to go to a neurologist quickly then, I guess.

Your symptoms sound like those of a transient ischemic attack, which commonly preempt a stroke. You should take these very seriously.

Do you have the deja vu experience every time? I have noticed that I get that a lot when I'm stressed or sleep deprived. I always thought it was just som random brain event but could it be a symptom of some kind of disorder or damage that only surfaces during physical low points?

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.

Wow I thought this was normal. I've been experiencing this for years. It's not a frightening experience at all, and hasn't been getting worse. All kinds of odd pops, tingling sensations, and flashes of deja Vu. One time I had about 20 deja Vu experiences in the course of 10 minutes.

Do take it seriously. SUDEP [1] is a serious condition. My partner died from it a few years ago.

[1]: https://en.wikipedia.org/wiki/Sudden_unexpected_death_in_epi...

> 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

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.

Yeah... 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.

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?

This 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.

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

My guess from having formerly been married to a chemist is that machine-based chemistry is one of the most difficult areas of science. Chemistry is still equal parts art and science in that the techniques that will give accurate scientific results depend greatly on the types of things being measured for. For detecting a particular substance, there may or may not be a cheap or viable detecting device that could be built, depending on whether that thing is normally detected by chromatography, reaction with something else, spectroscopy, etc. For example, carbon monoxide detectors are great and cheap. But I think it's probably just really case by case. Chemistry is just super hard to generalize or systematize. I used to ask her why they don't have Star Trek tricorder type devices yet that can universally analyze substances, and that was more or less her answer.

Edit: for the difficulty of machine chemistry, see also the Theranos debacle.

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.)

I imagine it's probably that it's prohibitively expensive to make one with the qualities required, which is reliable, mobile, can alert others automatically, with a long running time.

Dogs (some breeds more than others) have some of the strongest smelling capabilities on the planet. So much so, that some people theorize that one of the reasons dogs don't traditionally do all that well on the mirror self-recognition test is that it focuses on vision, and as animals that rely so heavily on such a strong smelling capability, it may throw them off (I guess the human equivalent would be if the test was audio only, or audio with a very fuzzy image. If you weren't already familiar with hearing your voice played back to you, how likely would you be to recognize it as yours?)

The search space for which molecule or sets of molecules are being recognized is huge. There are at least 120 different receptor types, and the dynamic range of their detection thresholds is large too. So we're looking at perhaps a trillion different combinations in theory.

Plus the detection threshold can be as low as parts per billion, spread across 300 million receptors in a dog.

So just the mathematics of the search space seem like a pretty good reason why it is a hard problem in general.

It'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.

Living things are machines, they're just incredibly sophisticated biological ones ;)

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.

The 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.

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

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)

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. =)

Or, maybe, humans have the olfactory capcities but these sensations are not transfered to the consious.

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

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

This is fascinating. If you do not mind me asking, what was the smell that you experienced?

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.

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

Off-topic but your post is grammatically perfect as far as I can tell. No need to apologize.

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.

And taste their pee.

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!)

It is falsifiable. E.g. you could sever dogs olfactory nerves and repeat the experiment.